Home

Red Hat Enterprise Linux 3 System Administration Guide

1. bus cycles this processor is driving HIT pin Profiler running O hours 59 mins 29 interrupts second total 49471 Flush profiler data Stop profiler Save and quit Figure 43 1 OProfile Setup On the right side of the tab select the Profile kernel option to count events in kernel mode for the currently selected event as discussed in Section 43 2 3 Separating Kernel and User space Profiles Chapter 43 OProfile 311 This is equivalent to the opcontrol ctrN kernel 1 command where N is the counter number If this option is unselected it is equivalent to the opcontrol ctrN kernel 0 command Select the Profile user binaries option to count events in user mode for the currently selected event as discussed in Section 43 2 3 Separating Kernel and User space Profiles This is equivalent to the opcontrol ctrN user 1 command where N is the counter number If this option is unselected it is equivalent to the opcontrol ctrN user 0 command Use the Count text field to set the sampling rate for the currently selected event as discussed in Section 43 2 2 1 Sampling Rate If any unit masks are available for the currently selected event as discussed in Section 43 2 2 2 Unit Masks they are displayed in the Unit Masks area on the right side of the Setup tab Select the checkbox beside the unit mask to enable it for the event On the Configuration tab to profile the ke
2. Protie status Device Nickname Type 7 active e e eme vV J Active etho etho Ethernet Figure 19 1 Network Administration Tool If you prefer modifying the configuration files directly refer to the Red Hat Enterprise Linux Refer ence Guide for information on their locations and contents 124 Chapter 19 Network Configuration Om Go to the Red Hat Hardware Compatibility List http hardware redhat com hcl to determine if Red Hat Enterprise Linux supports your hardware device 19 1 Overview To configure a network connection with the Network Administration Tool perform the following steps 1 Add a network device associated with the physical hardware device 2 Add the physical hardware device to the hardware list if it does not already exist 3 Configure the hostname and DNS settings 4 Configure any hosts that cannot be looked up through DNS This chapter discusses each of these steps for each type of network connection 19 2 Establishing an Ethernet Connection To establish an Ethernet connection you need a network interface card NIC a network cable usually a CATS cable and a network to connect to Different networks are configured to use different network speeds make sure your NIC is compatible with the network to which you want to connect To add an Ethernet connection follow these steps 1 Click the Devices tab 2 Click the New button on the toolbar
3. 31 2 Time Zone Configuration 232 32 Keyboard Configuration 233 33 Mouse Configuration 235 34 X Window System Configuration sssessssseesesessistesesressrtstsstsesstsrsstrssrsrtntsrenrentnronesrent 237 34 1 Display Set gs ssn snet i E a E E S AR 237 34 2 Advanced Settings 35 User and Group Configuration ccceeseesceeecseseesesescscseeesesssssssecseesssseseanaeseas 239 35 li Adding a New Usein merna eenaa ir a 239 35 2 Modifying User Properties 240 35 3 Adding a New Group 241 35 4 Modifying Group Properties 35 5 Command Line Configuration 35 6 Explaining the Process ree ia E E TE E 245 35 7 Additional Information ccseceseeseeseseeseteeseeeeseeecseeecseeeeseeseeeeaeeecaeeeeeeeaeeeeas 246 36 Printer Conf SUratiOn eae anrs e e a aa 36 1 Adding a Local Printer 36 2 Adding an IPP Printer 00 0 36 3 Adding a Remote UNIX LPD Printer 36 4 Adding a Samba SMB Printer 36 5 Adding a Novell NetWare NCP Printer 254 36 6 Adding a JetDirect Printer 0 255 36 7 Selecting the Printer Model and Finishing cece tees eeeeeeeeeee 256 36 8 Printing a Test Paget avscisc cess cnauseatscsest evel E ER a atai 36 9 Modifying Existing Printers j 36 10 Saving the Configuration File sseni n E 260 36 11 Command Line Configuration 00 0 cece esceeeeeceeseeeseeeeseseeeeteeseensees 260 36 12 Managing Print Jobs
4. Figure 19 20 Home Profile You can also configure eth0 to activate in the Office profile only and to activate a ppp modem device in the Home profile only Another example is to have the Common profile activate eth0 and an Away profile activate a ppp device for use while traveling To activate a profile at boot time modify the boot loader configuration file to include the netprofile lt profilename gt option For example if the system uses GRUB as the boot loader and boot grub grub conf contains title Red Hat Enterprise Linux 2 4 21 1 1931 2 399 ent root hd0 0 kernel vmlinuz 2 4 21 1 1931 2 399 ent ro root LABEL initrd initrd 2 4 21 1 1931 2 399 ent img modify it to the following where lt profilename gt is the name of the profile to be activated at boot time title Red Hat Enterprise Linux 2 4 21 1 1931 2 399 ent root hd0 0 kernel vmlinuz 2 4 21 1 1931 2 399 ent ro root LABEL netprofile lt profilename gt initrd initrd 2 4 21 1 1931 2 399 ent img To switch profiles after the system has booted go to Main Menu on the Panel gt System Tools gt Network Device Control or type the command redhat cont rol network to select a profile and activate it The activate profile section only appears in the Network Device Control interface if more than the default Common interface exists Alternatively execute the following command to enable a profile replace lt profilename gt with the name of the profil
5. You may configure network devices associated with 3 physical hardware here Multiple logical devices can be T associated with a single piece of hardware Profile Status Device Nickname type yy Inactive pppO Provider xDSL Figure 19 9 xDSL Device Be sure to select File gt Save to save the changes After adding the xDSL connection you can edit its configuration by selecting the device from the device list and clicking Edit For example when the device is added it is configured not to start at boot time by default Edit its configuration to modify this setting When the device is added it is not activated immediately as seen by its Inactive status To activate the device select it from the device list and click the Activate button If the system is configured to activate the device when the computer starts the default this step does not have to be performed again 19 6 Establishing a Token Ring Connection A token ring network is a network in which all the computers are connected in a circular pattern A token or a special network packet travels around the token ring and allows computers to send information to each other For more information on using token ring under Linux refer to the Linux Token Ring Project website available at htto www linuxtr net To add a token ring connection follow these steps 1 Click the Devices tab 2 Click the New button on the t
6. File Preferences Help f e 8 Add Propertie Help Directory Permissions Description Figure 24 1 Samba Server Configuration Tool 172 Chapter 24 Samba gt Note The Samba Server Configuration Tool does not display shared printers or the default stanza that allows users to view their own home directories on the Samba server 24 2 1 1 Configuring Server Settings The first step in configuring a Samba server is to configure the basic settings for the server and a few security options After starting the application select Preferences gt Server Settings from the pulldown menu The Basic tab is displayed as shown in Figure 24 2 Basic Security Workgroup mygroup Description samba server 3 Cancel 2 OK Figure 24 2 Configuring Basic Server Settings On the Basic tab specify which workgroup the computer should be in as well as a brief description of the computer They correspond to the workgroup and server string options in smb conf Basic Security Authentication Mode User z Authentication Server Encrypt Passwords Yes z Guest Account No guest account t 3e Cancel 2 OK Figure 24 3 Configuring Security Server Settings The Security tab contains the following options Authentication Mode This corresponds to the security option Select one of the f
7. 262 36 13 Sharing a Printer 264 36 14 Additional Resources 266 37 Automated Tasks c008 267 37 1 Cron 267 STD sAV and BAC a NE E E gies EE E 269 31 3 Additon l RESOULCES 25 oireita rooe r EErEE EI EEE E EPSEN SEE TEASE eest 271 38 Log Files 38 1 Locating Log Files noraino sse EEEE AEA EEE R i 273 38 2 Viewing Log Files aaraa oo aaa a aa ATEAN AE E EEA Ar 38 3 Adding a Log File 38 4 Examinin gs Log Piles inresa n eerie sS AATE EEES SPENSE E a eiis 275 39 Upsrading the Keine ranna ennaa e EERE A E AE AE AE Aa E EEEa AN 277 39 1 Overview of Kernel Packages 277 39 2 Preparing to Upgrade 0 278 39 3 Downloading the Upgraded Kernel 279 39 4 Performing the Upgrade 279 39 5 Verifying the Initial RAM Disk Image 280 39 6 Verifying the Boot Loader siosaia ainai 280 40 Kernel Modules arnor aen ate A EAO EAA SAE EE TER PESETAS 40 1 Kernel Module Utilities 40 2 Additional Resources 005 41 Mail Transport Agent MTA Configuration VI System Monitoring 42 Gathering System Information ceceesesseeeseeseseeseeseseeeeaeeceseeseseesesceseeeaeeeeseeaeeeeaeeneaes 42 1 System Processes 42 2 Memory Usage 42 3 File Systems 42 4 Hardware 42 5 Additional Resources 43 OProfile arisini 43 1 Overview of Tools i 43 2 Configuring OProfiles ssec ssiri teare o SASE sde 43 3 Starting
8. C Force to be a primary partition asprimary Make partition on specific drive ondisk Drive for example hda or sdc C Use existing partition onpart Partition for example hdal or sdc3 Format partition amp Cancel Figure 10 5 Creating Partitions Chapter 10 Kickstart Configurator To edit an existing partition select the partition from the list and click the Edit button The same Partition Options window appears as when you chose to add a partition as shown in Figure 10 5 except it reflects the values for the selected partition Modify the partition options and click OK To delete an existing partition select the partition from the list and click the Delete button 10 4 1 1 Creating Software RAID Partitions Refer to Chapter 3 Redundant Array of Independent Disks RAID to learn more about RAID and the different RAID levels RAID 0 1 and 5 can be configured To create a software RAID partition use the following steps 1 Click the RAID button 2 Select Create a software RAID partition 3 Configure the partitions as previously described except select Software RAID as the file system type Also you must specify a hard drive on which to make the partition or specify an existing partition to use Chapter 10 Kickstart Configurator 69 Mount Point File System Type software RAID eel lt Size MB 2048 Additional Size Options Fixed siz
9. Contact your system administrator for the values to use Configure Tunnel Device cipcbO ed Tunnel through Device None Server Mode v Local Port 7777 Remote Peer Address Server Mode 7 auto Remote Peer Port Remote Virtual Address y 7 Local Virtual Address Secret Key Generate Configuration for your remote partner IP Address of Tunnel Device Server Mode S Local Port own choice Remote Peer Address 0 0 0 0 auto 7777 Remote Virtual Address Local Virtual Address X 3 Cancel lt Back D Eorward Figure 19 12 CIPE Settings 4 Click Apply on the Create CIPE Connection page After configuring the CIPE device it appears in the device list as shown in Figure 19 13 Chapter 19 Network Configuration 133 File Profile Help arf Bg xX New Edit Copy Delete Activate Deactivate Devices Hardware IPsec DNS Hosts lt j You may configure network devices associated with 3 physical hardware here Multiple logical devices can be T associated with a single piece of hardware Profile Status Device Nickname Type IV Inactive cipcbi cipcbo CIPE Figure 19 13 CIPE Device Be sure to select File gt Save to save the changes After adding the device you can edit its configuration by selecting the device from the device list an
10. Display the output in a specific column order This option can not be used with g Use the following letters to represent the columns 308 Chapter 43 OProfile s Number of samples o s Cumulative number of samples o p Percentage of samples relative to total number of samples for the executable _ Cumulative percentage of samples relative to total number of samples for the executable a Percentage of samples relative to all executables sampled o Cumulative percentage of samples relative to all executables sampled a Symbotname o z Base name of the executable o a Derails ofthe sample o Table 43 4 Letters for Column Order session lt name gt Specify the full path to the session or a directory relative to the var lib oprofile samples directory p lt path list gt Specify a comma separated list of paths in which the executables to be analyzed are located 43 5 3 Using op_to_source The op_to_source tool tries to match the samples for particular instructions to the corresponding lines in the source code The resulting files generated should have the samples for the lines at the left It also puts in a comment at the beginning of each function listing the total samples for the function For this utility to work the executable must be compiled with GCC s g option By default Red Hat Enterprise Linux packages are not compiled with this option The general syntax for op_to_source is as follows o
11. RAID Device mdo Y RAID Level RAIDO T 7 hda 2996 MB 7 hda3 2996 MB RAID Members Number of spares 0 X Cancel ok Figure 12 3 Making a RAID Device 4 Enter a mount point 5 Choose the file system type for the partition 6 Select a device name such as md0 for the RAID device 7 Choose your RAID level You can choose from RAID 0 RAID 1 and RAID 5 Note If you are making a RAID partition of boot you must choose RAID level 1 and it must use one of the first two drives IDE first SCSI second If you are not creating a RAID partition of poot and you are making a RAID partition of it must be RAID level 1 and it must use one of the first two drives IDE first SCSI second Chapter 12 Software RAID Configuration 85 8 The RAID partitions you just created appear in the RAID Members list Select which partitions of these partitions should be used to create the RAID device 9 If configuring RAID 1 or RAID 5 specify the number of spare partitions If a software RAID partition fails the spare will automatically be used as a replacement For each spare you want to specify you must create an additional software RAID partition in addition to the partitions for the RAID device In the previous step select the partitions for the RAID device and the partition s for the spare s 10 After clicking OK the RAID device will appear in the Drive Su
12. C Force to be a primary partition Cancel 2 OK Figure 13 1 Creating a Physical Volume 4 You will not be able to enter a mount point you will be able to do that once you have created your volume group 5 A physical volume must be constrained to one drive For Allowable Drives select the drive on which the physical volume will be created If you have multiple drives all drives will be selected and you must deselect all but one drive 88 Chapter 13 LVM Configuration 6 Enter the size that you want the physical volume to be 7 Select Fixed size to make the physical volume the specified size select Fill all space up to MB and enter a size in MBs to give range for the physical volume size or select Fill to maximum allowable size to make it grow to fill all available space on the hard disk If you make more than one growable they will share the available free space on the disk 8 Select Force to be a primary partition if you want the partition to be a primary partition 9 Click OK to return to the main screen Repeat these step to create as many physical volumes as needed for your LVM setup For example if you want the volume group to span over more than one drive create a physical volume on each of the drives waming The boot partition can not be on a volume group because the boot loader can not read it If you want to have your root partition on a logical volume you will need to creat
13. If DHCP is specified and the bootfile begins with a the bootfile provided by DHCP is looked for on the NFS server If DHCP is specified and the bootfile begins with something other then a the bootfile pro vided by DHCP is looked for in the kickstart directory on the NFS server If DHCP did not specify a bootfile then the installation program tries to read the file kickstart 1 2 3 4 kickstart where 1 2 3 4 is the numeric IP address of the machine being installed ksdevice lt device gt The installation program will use this network device to connect to the network For example to start a kickstart installation with the kickstart file on an NFS server that is connected to the system through the ethl device use the command ks nfs lt server gt lt path gt ksdevice ethl at the boot prompt 62 Chapter 9 Kickstart Installations amp redhat Chapter 10 Kickstart Configurator Kickstart Configurator allows you to create or modify a kickstart file using a graphical user interface so that you do not have to remember the correct syntax of the file To use Kickstart Configurator you must be running the X Window System To start Kickstart Configurator select the Main Menu Button on the Panel gt System Tools gt Kickstart or type the command usr sbin redhat config kickstart As you are creating a kickstart file you can select File gt Preview at any time to review your current selections To start with a
14. RPM packages can depend on other packages which means that they require other packages to be installed to run properly If you try to install a package which has an unresolved dependency output similar to following is displayed Preparing HAT RAAT HATE HATH HAA AHH EE 100 error Failed dependencies bar so 2 is needed by foo 1 0 1 Suggested resolutions bar 2 0 20 3 1386 rpm If you are installing a package from the Red Hat Enterprise Linux CD ROM set it usually suggest the package s need to resolve the dependency Find this package on the Red Hat Enterprise Linux CD ROMs or from the Red Hat FTP site or mirror and add it to the command rpm ivh foo 1 0 1 1386 rpm bar 2 0 20 3 1386 rpm If installation of both packages is successful output similar to the following is displayed Preparing HEAR AE AE AE AE AE AE ARE AEA AE AE AE AE E AE AE ARE AEA EE EAE aE AEE aE AEE HE aE AE EAE 1005 1 fo00 TRAE A AE E AE AE AE AE AE E AEE aE AE E AE AE AEE EAE AE HE EE aE AEE EEEE EEE D 505 2 bar AEAEE EAE E AE AE AE AE AE E AE E AE E AE E AE E AEE AE EAE HE EAEE EEEE EEE E 1003 If it does not suggest a package to resolve the dependency you can try the redhatprovides option to determine which package contains the required file You need the rpmdb redhat package installed to use this options rpm q redhatprovides bar so 2 If the package that contains bar so 2 is in the installed database from the rpmdb redhat package the
15. We can combine the above two examples in the following scenario Say you are having problems with usr bin paste You would like to verify the package that owns that program but you do not know which package owns paste Simply enter the following command Chapter 16 Package Management with RPM 111 rpm Vf usr bin paste and the appropriate package is verified e Do you want to find out more information about a particular program You can try the following command to locate the documentation which came with the package that owns that program rpm qdf usr bin free The output would be like the following usr share doc procps 2 0 11 BUGS usr share doc procps 2 0 11 NEWS usr share doc procps 2 0 11 TODO usr share man manl free 1 gz usr share man manl oldps 1 gz usr share man manl pgrep 1 gz usr share man manl pkill 1 gz usr share man manl ps 1 gz usr share man manl skill 1 gz asr share man manl snice 1 gz usr share man manl tload 1 gz asr share man manl top 1 gz asr share man manl uptime 1 gz usr share man manl w 1 gz asr share man manl watch 1 gz asr share man man5 sysctl conf 5 gz asr share man man8 sysct1 8 gz asr share man man8 vmstat 8 gz You may find a new RPM but you do not know what it does To find information about it use the following command rpm qip crontabs 1 10 5 noarch rpm The output would look like the following Name crontabs Relocations not relocateable Version 3 1 10 Vendor R
16. gt System Set tings gt Mouse or type the command redhat config mouse at a shell prompt for example in an XTerm or GNOME terminal If the X Window System is not running the text based version of the tool is started Select the appropriate mouse for the system gt 2 Button Mouse USB 3 Button Mouse USB 3 Button Mouse serial Wheel Mouse USB 2 Button Mouse serial 2 Button Mouse PS 2 3 Button Mouse PS 2 gt Kensington Emulate 3 button click Serial devices OK Figure 33 1 Select Mouse Select the new mouse type for the system If there is not an exact match select one that is most compatible with the system and the mouse The built in pointing device such as a touch pad on a laptop computer is usually PS 2 compatible All the mouse types are appended with PS 2 serial or USB in parentheses This specifies the mouse port A PS 2 mouse port looks similar to A serial mouse port looks similar to Ces A USB mouse port looks similar to If the specific mouse model is not listed select one of the Generic entries based on the mouse s number of buttons and its interface o Z Select the Generic Wheel Mouse entry with the proper mouse port to enable the scroll button on the mouse 236 Chapter 33 Mouse Configuration The scroll button on a wheel mouse can be used as the middle mouse button for cutting text pasting t
17. ia64 for the Intel Itanium architecture ppc64pseries for the IBM eServer pSeries architecture ppc64iseries for the IBM eServer iSeries architecture 390 for the IBM S 390 architecture 390x for the IBM eServer zSeries architecture DAUA WN x86 variant The x86 kernels are optimized for different x86 versions The options are as follows athlon for AMD Athlon and AMD Duron systems i686 for Intel Pentium II Intel Pentium III and Intel Pentium 4 systems 39 3 Downloading the Upgraded Kernel There are several ways to determine if there is an updated kernel available for the system e Security Errata go to the following location for information on security errata including kernel upgrades that fix security issues http www redhat com apps support errata e Via Quarterly Updates refer to the following location for details http www redhat com apps support errata rhlas_errata_policy html e Use Red Hat Network to download the kernel RPM packages and install the packages Red Hat Network can download the latest kernel upgrade the kernel on the system create an initial RAM disk image if needed and configure the boot loader to boot the new kernel For more information refer to http www redhat com docs manuals RHNetwork If Red Hat Network was used to download and install the updated kernel following the instructions in Section 39 5 Verifying the Initial RAM Disk Ima
18. mygroup Cancel 2 OK Figure 35 5 Group Properties The Group Users tab displays which users are members of the group Select additional users to be added to the group or unselect users to be removed from the group Click OK to modify the users in the group 35 5 Command Line Configuration If you prefer command line tools or do not have the X Window System installed use this section to configure users and groups 35 5 1 Adding a User To add a user to the system 1 Issue the useradd command to create a locked user account useradd lt username gt 2 Unlock the account by issuing the passwd command to assign a password and set password aging guidelines passwd lt username gt Command line options for useradd are detailed in Table 35 1 Home directory to be used instead of default home username Date for the account to be disabled in the format YY Y Y MM DD Chapter 35 User and Group Configuration 243 Option Description o O Number of days after the password expires until the account is disabled If O is specified the account is disabled immediately after the password expires If 1 is specified the account is not be disabled after the password expires g group name Group name or group number for the user s default group The group must exist prior to being specified here G group list List of additional other than default group names or group numbers separated by
19. 2 Document Conventions When you read this manual certain words are represented in different fonts typefaces sizes and weights This highlighting is systematic different words are represented in the same style to indicate their inclusion in a specific category The types of words that are represented this way include the following Introduction iii command Linux commands and other operating system commands when used are represented this way This style should indicate to you that you can type the word or phrase on the command line and press Enter to invoke a command Sometimes a command contains words that would be displayed in a different style on their own such as file names In these cases they are considered to be part of the command so the entire phrase is displayed as a command For example Use the cat test file command to view the contents of a file named test file in the current working directory file name File names directory names paths and RPM package names are represented this way This style should indicate that a particular file or directory exists by that name on your system Examples The bashrc file in your home directory contains bash shell definitions and aliases for your own use The etc fstab file contains information about different system devices and file systems Install the webalizer RPM if you want to use a Web server log file analysis program application This style indicates that
20. 25 etc fstab modifying 21 creating quota files 22 quotacheck running 22 grace period 23 hard limit 23 management of 24 quotacheck command using to check 24 reporting 24 soft limit 23 disk storage See disk quotas parted See parted diskless environment 97 adding hosts 99 DHCP configuration 94 98 Network Booting Tool 98 NFS configuration 98 overview 97 display settings for X 237 documentation finding installed 111 DSA keys generating 160 DSOs loading 204 du 296 Dynamic Host Configuration Protocol See DHCP E e2fsck 2 e2label 18 emergency mode 82 Ethernet connection See network configuration expiration of password forcing 243 exporting NFS file Systems 165 exports 167 ext2 reverting from ext3 2 ext3 converting from ext2 2 creating 2 features 1 F feedback v file systems 296 ext2 See ext2 ext3 See ext3 LVM See LVM NFS See NFS findsmb 178 firewall configuration See Security Level Configuration Tool floppy group use of 230 free 295 ftp 157 G getfacl 33 GNOME Print Manager 262 change printer settings 262 GNOME System Monitor 294 gnome system monitor 294 GnuPG checking RPM package signatures 109 group configuration adding groups 241 additional information 246 filtering list of groups 239 groupadd 243 modify groups for a user 240 modify users in groups 242 modifying group properties 242 viewing list of groups 239 groups
21. Chapter 24 Samba 177 Om To view active connections to the system execute the command smbstatus 24 3 Connecting to a Samba Share You can use Nautilus to view available Samba shares on your network Select Main Menu Button on the Panel gt Network Servers to view a list of Samba workgroups on your network You can also type smb in the Location bar of Nautilus to view the workgroups As shown in Figure 24 6 an icon appears for each available SMB workgroup on the network Ele Edt view Go Bookmarks Help d1 gt AOGA A O Back Foward Up Stop Reload Home a View as Icons Location smb i m m m m 08 iS 0B iA a OS WORKGROUP WORKGROUP selected 0 bytes Figure 24 6 SMB Workgroups in Nautilus Double click one of the workgroup icons to view a list of computers within the workgroup Ele Edt view Go Bookmarks Help I gt AGAJ A Back Foward Up Stop Reload Home ao View as Icons Location smb workgroup H 4 ag 4 FALCON PIGDOG PINKY YETI WORKGROUP selected 0 bytes Figure 24 7 SMB Machines in Nautilus 178 Chapter 24 Samba As you can see from Figure 24 7 there is an icon for each machine within the workgroup Double click on an icon to view the Samba shares on the machine If a username and password combination is required you are prompted for them Alternately you can also specify the Samba server and s
22. Directory usea Space Total Space dev hda1 boot 22 3 MB 98 7 MB dev hda2 4 0 GB 18 6 GB Figure 42 2 GNOME System Monitor 42 3 File Systems The df command reports the system s disk space usage If you type the command df at a shell prompt the output looks similar to the following Filesystem 1k blocks Used Available Use Mounted on dev hda2 10325716 2902060 6899140 30 dev hdal 15554 8656 6095 59 boot dev hda3 20722644 2664256 17005732 14 home none 256796 0 256796 0 dev shm By default this utility shows the partition size in 1 kilobyte blocks and the amount of used and avail able disk space in kilobytes To view the information in megabytes and gigabytes use the command df h The hn argument stands for human readable format The output looks similar to the following Filesystem Size Used Avail Use Mounted on dev hda2 9 8G 2 8G 6 5G 30 dev hdal 15M 8 5M 5 9M 59 boot dev hda3 20G 2 6G 16G 14 home none 251M 0 250M 0 dev shm In the list of partitions there is an entry for dev shm This entry represents the system s virtual memory file system The du command displays the estimated amount of space being used by files in a directory If you type du at a shell prompt the disk usage for each of the subdirectories will be displayed in a list The grand total for the current directory and subdirectories will also be shown as the last line in the list If you do not want to see the totals for al
23. Hardware Software Problems This category includes a wide variety of different situations Two examples include failing hard drives and specifying an invalid root device or kernel in the boot loader configuration file If either of these occur you might not be able to reboot into Red Hat Enterprise Linux However if you boot into one of the system recovery modes you might be able to resolve the problem or at least get copies of your most important files 11 1 3 Root Password What can you do if you forget your root password To reset it to a different password boot into rescue mode or single user mode and use the passwd command to reset the root password 80 Chapter 11 Basic System Recovery 11 2 Booting into Rescue Mode Rescue mode provides the ability to boot a small Red Hat Enterprise Linux environment entirely from a diskette CD ROM or some other boot method instead of the system s hard drive As the name implies rescue mode is provided to rescue you from something During normal oper ation your Red Hat Enterprise Linux system uses files located on your system s hard drive to do everything run programs store your files and more However there may be times when you are unable to get Red Hat Enterprise Linux running completely enough to access files on your system s hard drive Using rescue mode you can access the files stored on your system s hard drive even if you cannot actually run Red Hat Enterprise Linux fr
24. If you associate more than one device with an Ethernet card the subsequent devices are device aliases A device alias allows you to setup multiple virtual devices for one physical device thus giving the one physical device more than one IP address For example you can configure an eth device and an eth1 1 device For details refer to Section 19 13 Device Aliases 126 Chapter 19 Network Configuration 19 3 Establishing an ISDN Connection An ISDN connection is an Internet connection established with a ISDN modem card through a special phone line installed by the phone company ISDN connections are popular in Europe To add an ISDN connection follow these steps 1 Click the Devices tab 2 Click the New button on the toolbar 3 Select ISDN connection from the Device Type list and click Forward 4 Select the ISDN adapter from the pulldown menu Then configure the resources and D channel protocol for the adapter Click Forward to continue Select ISDN Adapter a ISDN Adapters ACER P10 Fl Resource D Channel Protocol IRQ 5 Eur ISDN EDSS1 MEM Ours 10o ox300 Cancel lt Back D Eoward Figure 19 4 ISDN Settings 5 If your Internet Service Provider ISP is in the pre configured list select it Otherwise enter the required information about your ISP account If you do not know the values contact your ISP Click Forward 6 In the IP Settings window select the
25. Partition Information Authentication Firewall Configuration X Configuration Package Selection Pre installation Script Post installation Script Device Delete Network Device Figure 10 8 Network Configuration If the system to be installed via kickstart does not have an Ethernet card do not configure one on the Network Configuration page Networking is only required if you choose a networking based installation method NFS FTP or HTTP Networking can always be configured after installation with the Network Administration Tool redhat config network Refer to Chapter 19 Network Configuration for details For each Ethernet card on the system click Add Network Device and select the network device and network type for the device Select eth0 to configure the first Ethernet card eth1 for the second Ethernet card and so on Chapter 10 Kickstart Configurator 10 6 Authentication File Help Basic Configuration Installation Method Boot Loader Options Partition Information Network Configuration Firewall Configuration X Configuration Package Selection Pre Installation Script Post installation Script Authentication Configuration Authentication Use Shadow Passwords Use MDS NIS LDAP Kerberos 5 Hesiod SMB Name Switch Cache NIS Authentication Enable NIS Figure 10 9 Authentication 71 In th
26. See Also Log Viewer description 273 examining 275 locating 273 rotating 273 syslogd 273 viewing 273 Log Viewer alerts 275 filtering 273 log file locations 274 refresh rate 274 searching 273 logical volume 13 89 logical volume group 13 87 Logical Volume Manager See LVM logrotate 273 Ipd 250 lsmod 285 lspci 297 LVM 13 additional resources 14 configuring LVM during installation 87 explanation of 13 logical volume 13 89 logical volume group 13 87 physical extent 88 physical volume 13 87 with kickstart 48 Mail Transport Agent See MTA Mail Transport Agent Switcher 289 starting in text mode 289 Mail User Agent 289 Master Boot Record 79 MDS passwords 221 memory usage 295 mkfs 17 mkpart 17 modem connection See network configuration modprobe 286 modules conf 285 monitor settings for X 237 mounting NFS file systems 163 323 MTA setting default 289 switching with Mail Transport Agent Switcher 289 MUA 289 N named conf 213 neat See network configuration netcfg See network configuration Network Administration Tool See network configuration Network Booting Tool 91 pxeboot 94 pxeos 92 using with diskless environments 98 using with PXE installations 91 network configuration activating devices 137 CIPE connection 132 activating 133 device aliases 139 DHCP 124 Ethernet connection 124 activating 125 IPsec host to host 141 IPsec network
27. Tells the system to upgrade an existing system rather than install a fresh system You must specify one of cdrom harddrive nfs or url for ftp and http as the location of the installation tree Refer to install for details xconfig optional Configures the X Window System If this option is not given the user will need to configure X manually during the installation if X was installed this option should not be used if X is not installed on the final system noprobe Do not probe the monitor card Use specified card this card name should be from the list of cards in usr share hwdata Cards from the hwdata package The list of cards can also be found on the X Configuration screen of the Kickstart Configurator If this argument is not provided the installation program will probe the PCI bus for the card Since AGP is part of the PCI bus AGP cards will be detected if supported The probe order is determined by the PCI scan order of the motherboard videoram Specify the amount of video RAM the video card has monitor Use specified monitor monitor name should be from the list of monitors in usr share hwdata MonitorsDB from the hwdata package The list of monitors can also be found on the X Configuration screen of the Kickstart Configurator This is ignored if hsync or vsync is provided If no monitor information is provided the installation program tries to probe for it automatically 54 Chapter 9 Ki
28. The sbin modprobe command checks for these dependencies and loads the module dependencies before loading the specified module For example the command sbin modprobe hid loads any module dependencies and then the hid module To print to the screen all commands as sbin modprobe executes them use the v option For example sbin modprobe v hid Output similar to the following is displayed sbin insmod lib modules 2 4 21 1 1931 2 399 ent kernel drivers usb hid o Using lib modules 2 4 21 1 1931 2 399 ent kernel drivers usb hid o Symbol version prefix smp_ The sbin insmod command also exists to load kernel modules however it does not resolve de pendencies Thus it is recommended that the sbin modprobe command be used Chapter 40 Kernel Modules 287 To unload kernel modules use the sbin rmmod command followed by the module name The rmmod utility only unloads modules that are not in use and that are not a dependency of other modules in use For example the command sbin rmmod hid unloads the hid kernel module Another useful kernel module utility is modinfo Use the command sbin modinfo to display information about a kernel module The general syntax is sbin modinfo options lt module gt Options include d which displays a brief description of the module and p which lists the parameters the module supports For a complete list of options refer to the modinfo man page man modinfo 40 2 Additiona
29. accept the default value of bin bash The default home directory is home username You can change the home directory that is cre ated for the user or you can choose not to create the home directory by unselecting Create home directory If you select to create the home directory default configuration files are copied from the etc skel directory into the new home directory Red Hat Enterprise Linux uses a user private group UPG scheme The UPG scheme does not add or change anything in the standard UNIX way of handling groups it offers a new convention Whenever you create a new user by default a unique group with the same name as the user is created If you do not want to create this group unselect Create a private group for the user To specify a user ID for the user select Specify user ID manually If the option is not selected the next available user ID starting with number 500 is assigned to the new user Red Hat Enterprise Linux reserves user IDs below 500 for system users Click OK to create the user User Name tfox Full Name Tammy Fox Password tok teh a Confirm Password secant Login Shell bin bash lt Create home directory Home Directory home tfox lt Create a private group for the user Specify user ID manually 38 Cancel 2 OK Figure 35 2 New User To configure more advanced user properties such as password expiration modify the
30. create the directory if it does not exist and execute the fol lowing command as root mount t smbfs o username lt username gt lt servername gt lt sharename gt mnt point This command mounts lt sharename gt from lt servername gt in the local directory mnt point 24 4 Additional Resources For configuration options not covered here please refer to the following resources 24 4 1 Installed Documentation smb conf man page explains how to configure the Samba configuration file smbd man page describes how the Samba daemon works smbclient and findsmb man pages learn more about these client tools Chapter 24 Samba 179 e usr share doc samba lt version number gt docs help files included with the samba package 24 4 2 Useful Websites http www samba org The Samba webpage contains useful documentation information about mailing lists and a list of GUI interfaces http www samba org samba docs using_samba toc html an online version of Using Samba 2nd Edition by Jay Ts Robert Eckstein and David Collier Brown O Reilly amp Associates 180 Chapter 24 Samba redhat Chapter 25 Dynamic Host Configuration Protocol DHCP Dynamic Host Configuration Protocol DHCP is a network protocol for automatically assigning TCP IP information to client machines Each DHCP client connects to the centrally located DHCP server which returns that client s network configuration incl
31. dk dk latinl dvorak es et fi fi latinl fr fr latin0O fr latinl fr pc LECH fr_CH latinl gr hu hul01 is latinl it it ibm it2 jp106 la latinl mk utf no no latinl pl pt latinl ro_win ru ru cpl1251 ru ms rul ru2 ru_win se latinl sg sg latinl sk qwerty slovene speakup speakup lt sv latinl sg sg latinl sk querty slovene trq ua uk us us acentos The file usr lib python2 2 site packages rhpl keyboard_models py also contains this list and is part of the rhp1 package lang required Sets the language to use during installation For example to set the language to English the kickstart file should contain the following line lang en_US The file usr share redhat config language locale list provides a list the valid language codes in the first column of each line and is part of the redhat config languages package langsupport required Sets the language s to install on the system The same language codes used with lang can be used with Langsupport To install one language specify it For example to install and use the French language fr_FR langsupport fr_FR 48 Chapter 9 Kickstart Installations default If language support for more than one language is specified a default must be identified For example to install English and French and use English as the default language langsupport default en_US fr_FR If you use default with only one language all languages will be in
32. eg company My Company Ltd My Company Inc Organizational Unit Name eg section Documentation Common Name your name or server s hostname myhost example com Email Address myemail example com After you provide the correct information a self signed certificate is created in etc httpd conf ssl crt server crt Restart the secure server after generating the certificate with following the command sbin service httpd restart 27 9 Testing The Certificate To test the test certificate installed by default a CA signed certificate and a self signed certificate point your Web browser to the following home page replacing server example com with your domain name https server example com Note Note the s after http The https prefix is used for secure HTTP transactions If you are using a CA signed certificate from a well known CA your browser probably automatically accepts the certificate without prompting you for input and creates the secure connection Your browser does not automatically recognize a test or a self signed certificate because the certificate is not signed by a CA If you are not using a certificate from a CA follow the instructions provided by your browser to accept the certificate Once your browser accepts the certificate your secure server displays a default home page 27 10 Accessing The Server To access your secure server use a URL similar to the following https server ex
33. for example in an XTerm or a GNOME terminal File Actions Edit Runlevel Help gt aj U Start Stop Restart Save Revert Currently Running in Runlevel 5 Editing Runlevel 5 Description Startup shutdown script for the Common UNIX cups Printing System CUPS cups Ipd crond daytime _ daytime udp dbskkd cdb dhcpd dhcrelay echo echo udp Status cupsd pid 1961 is running eklogin finger firstboot v gpm gssftp x hpoj httpd identd Figure 21 1 Services Configuration Tool The Services Configuration Tool displays the current runlevel as well as the runlevel you are cur rently editing To edit a different runlevel select Edit Runlevel from the pulldown menu and select runlevel 3 4 or 5 Refer to Section 21 1 Runlevels for a description of runlevels The Services Configuration Tool lists the services from the etc rc d init d directory as well as the services controlled by xinetd Click on the name of the service from the list on the left hand side of the application to display a brief description of that service as well as the status of the service If the service is not an xinetd service the status window shows whether the service is currently running If the service is controlled by xinetd the status window displays the phrase xinetd service To start s
34. nections to SSH servers including the following ssh a secure replacement for rsh sftp a secure replacement for ftp for transferring files between machines and slogin a secure re placement for rlogin for remote login and telnet for communicating with another host via the Telnet protocol For more information about OpenSSH see Chapter 22 OpenSSH the Red Hat Enterprise Linux Reference Guide and the OpenSSH website at http www openssh com openss1l devel The openss1 devel package contains the static libraries and the include file needed to compile applications with support for various cryptographic algorithms and protocols You need to install this package only if you are developing applications which include SSL support you do not need this package to use SSL stunnel The stunnel package provides the Stunnel SSL wrapper Stunnel supports the SSL encryption of TCP connections so it can provide encryption for non SSL aware daemons and protocols such as POP IMAP and LDAP without requiring any changes to the daemon s code Table 27 1 displays a summary of the secure server packages and whether or not each package is optional for the installation of a secure server Package Name Optional httpd Chapter 27 Apache HTTP Secure Server Configuration 205 lt gt lt __ 7 Petpazaeve ves Table 27 1 Security Packages 27 3 An Overview of Certificates and Security Your secure server provid
35. the portmap and ypbind services are started and are also enabled to start at boot time Enable LDAP Support Select this option to configure the system to retrieve user information via LDAP Click the Configure LDAP button to specify the LDAP Search Base DN and LDAP Server If Use TLS to encrypt connections is selected Transport Layer Security is used to encrypt passwords sent to the LDAP server The openldap clients package must be installed for this option to work For more information about LDAP refer to the Red Hat Enterprise Linux Reference Guide Enable Hesiod Support Select this option to configure the system to retrieve information from a remote Hesiod database including user information The hesiod package must be installed 29 2 Authentication The Authentication tab allows for the configuration of network authentication methods To enable an option click the empty checkbox beside it To disable an option click the checkbox beside it to clear the checkbox Chapter 29 Authentication Configuration 221 User Information Authentication Use Shadow Passwords T Use MDS Passwords LDAP The Lightweight Directory Access Protocol is a standard way of searching a directory which can hold arbitrary data in a structured hierarchy LDAP is increasingly being used in small to large networks Enable LDAP Support Configure LDAP Kerberos Kerberos is a t
36. the username and password to access the printer should be different from the username and password used for the user s account on the local Red Hat Enterprise Linux system If they are different then the only possible security compromise would be unauthorized use of the printer If there are file shares from the server it is recommended that they also use a different password than the one for the print queue 36 6 Adding a JetDirect Printer To add a JetDirect printer click the New button in the main Printer Configuration Tool window The window shown in Figure 36 1 will appear Click Forward to proceed 256 Chapter 36 Printer Configuration In the window shown in Figure 36 3 enter a unique name for the printer in the Name text field The printer name cannot contain spaces and must begin with a letter The printer name may contain letters numbers dashes and underscores _ Optionally enter a short description for the printer which can contain spaces Select Networked JetDirect from the Select a queue type menu and click Forward Select a queue type Networked JetDirect Printer Port printer example com 9100 T Heip Cancel lt d Back gt Forward Figure 36 9 Adding a JetDirect Printer Text fields for the following options appear Printer The hostname or IP address of the JetDirect printer Port The port on the JetDirect printer that is listening f
37. with acl support option No special flags are required when accessing or mounting a Samba share 8 1 1 NFS By default if the file system being exported by an NFS server supports ACLs and the NFS client can read ACLs ACLs are utilized by the client system To disable ACLs on NFS shares when configuring the server include the no_acl option in the etc exports file To disable ACLs on an NFS share when mounting it on a client mount it with the no_acl option via the command line or the etc fstab file 8 2 Setting Access ACLs There are two types of ACLs access ACLs and default ACLs An access ACL is the access control list for a specific file or directory A default ACL can only be associated with a directory if a file within the directory does not have an access ACL it uses the rules of the default ACL for the directory Default ACLs are optional ACLs can be configured 32 Chapter 8 Access Control Lists 1 Per user 2 Per group 3 Via the effective rights mask 4 For users not in the user group for the file The set fac1 utility sets ACLs for files and directories Use the m option to add or modify the ACL of a file or directory setfacl m lt rules gt lt files gt Rules lt rules gt must be specified in the following formats Multiple rules can be specified in the same command if they are separated by commas u lt uid gt lt perms gt Sets the access ACL for a user The user name or UID may be specified Th
38. 1 for examples record the memory usage of the system every monday at 3 30AM in the file tmp meminfo 30 3 mon cat proc meminfo gt gt tmp meminfo run custom script the first day of every month at 4 10AM 10 4 1 root scripts backup sh Example 37 1 Crontab Examples Users other than root can configure cron tasks by using the crontab utility All user defined crontabs are stored in the var spool cron directory and are executed using the usernames of the users that created them To create a crontab as a user login as that user and type the command crontab e to edit the user s crontab using the editor specified by the VISUAL or EDITOR environment variable The file uses the same format as etc crontab When the changes to the crontab are saved the crontab is stored according to username and written to the file var spool cron username The cron daemon checks the etc crontab file the etc cron d directory and the var spool cron directory every minute for any changes If any changes are found they are loaded into memory Thus the daemon does not need to be restarted if a crontab file is changed 37 1 2 Controlling Access to Cron The etc cron allow and etc cron deny files are used to restrict access to cron The format of both access control files is one username on each line Whitespace is not permitted in either file The cron daemon crond does not have to be restarted if the access control files are modified
39. 13 87 Ww Windows file and print sharing 171 Windows 2000 connecting to shares using Samba 175 Windows 98 connecting to shares using Samba 175 Windows ME connecting to shares using Samba 175 Windows NT 4 0 connecting to shares using Samba 175 Windows XP connecting to shares using Samba 175 X X Configuration Tool advanced settings 237 display settings 237 X Window System configuration 237 xDSL connection See network configuration xinetd 152 Y ypbind 220 redhat Colophon The manuals are written in DocBook SGML v4 1 format The HTML and PDF formats are produced using custom DSSSL stylesheets and custom jade wrapper scripts The DocBook SGML files are written in Emacs with the help of PSGML mode Garrett LeSage created the admonition graphics note tip important caution and warning They may be freely redistributed with the Red Hat documentation The Red Hat Product Documentation Team consists of the following people Sandra A Moore Primary Writer Maintainer of the Red Hat Enterprise Linux Installation Guide for the x86 Itanium and AMD64 Architectures Primary Writer Maintainer of the Red Hat Enter prise Linux Installation Guide for the IBM eServer iSeries and IBM eServer pSeries Architectures Contributing Writer to the Red Hat Enterprise Linux Step By Step Guide Tammy Fox Primary Writer Maintainer of the Red Hat Enterprise Linux System Administration Guide
40. 163 etc fstab file enabling disk quotas with 21 etc hosts 136 etc httpd conf httpd conf 189 etc named custom 213 etc printcap 249 etc sysconfig devlabel 29 etc sysconfig dhepd 185 proc directory 298 var spool cron 268 A Access Control Lists See ACLs ACLs access ACLs 31 additional resources 34 archiving with 33 default ACLs 32 getfacl 33 mounting file systems with 31 mounting NFS shares with 31 on ext3 file systems 31 retrieving 33 setfacl 32 setting access ACLs 31 with Samba 31 adding group 243 user 242 Apache HTTP Server See HTTP Configuration Tool additional resources 201 related books 202 securing 205 APXS 204 at 269 additional resources 271 authconfig See Authentication Configuration Tool authconfig gtk See Authentication Configuration Tool authentication 219 Authentication Configuration Tool 219 authentication 220 Kerberos support 221 LDAP support 221 MDS passwords 221 shadow passwords 221 SMB support 222 command line version 222 user information 219 cache 220 Hesiod 220 LDAP 220 NIS 220 autofs 164 etc auto master 164 Automated Tasks 267 B batch 269 additional resources 271 BIND configuration 213 adding a forward master zone 214 adding a reverse master zone 215 adding a slave zone 217 applying changes 213 default directory 213 boot diskette 278 booting emergency mode 82 rescue mode 80 single user mode 81 C
41. 23 3 Exporting NFS File Systems i 23 4 Additional Resources 0 0 cceececesceseseeseseeecseesesecseeecseeeenecacnecseeseaeeaeaeeaeeaeaeeeenees 169 2A SAMBA n re SEE E E AT A E doc EE a E a 171 24 1 Why Use Samba 171 24 2 Configuring a Samba Server cccceccecesseseseeseseeseeeeseeeeseeeceeeseneeseeaeeeaeeeeeeeees 171 24 3 Connecting to a Samba Share cccccccecescseeseesenseseeeeseeeeeeseneeseeeeseeaeeeaeeeeeeeees 177 24 4 Additional Resources 178 25 Dynamic Host Configuration Protocol DHCP 25 1 Why Use DHCP uu eee 25 2 Configuring a DHCP Servers n R T R 181 25 32 Configuring a DHCP CHENE seeiis a R E 185 25 4 Additional Reso rteSi neea iaa EEE E E A a a itia 186 26 Apache HTTP Server Configuration 189 189 191 26 1 Basic Settings 26 2 Default Settings 26 3 Virtual Hosts Settings 196 26 4 Server Settings 199 26 5 Performance Tuning rhetor Eea sovises tees E ARSE 200 26 6 Saving Your Setting S orere ia Aa EE E Ee E A a ae iteli 201 26 7 Additional Resources 27 Apache HTTP Secure Server Configuration ccc ccesesseseeeecseseeeseesesesesseesaeseeeeeee 203 2 7 Nig KaKo L CHOW PSOE sss REET OT A AET 203 27 2 An Overview of Security Related Packages 27 3 An Overview of Certificates and Security 27 4 Using Pre Existing Keys and Certificates 27 5 Types of Certificates oo eee 206 27 6 Gene
42. 270 Chapter 37 Automated Tasks If the set of commands or script tries to display information to standard out the output is emailed to the user Use the command atq to view pending jobs Refer to Section 37 2 3 Viewing Pending Jobs for more information Usage of the at command can be restricted Refer to Section 37 2 5 Controlling Access to At and Batch for details 37 2 2 Configuring Batch Jobs To execute a one time task when the load average is below 0 8 use the bat ch command After typing the batch command the at gt prompt is displayed Type the command to execute press Enter and type Ctrl D More than one command can be specified by typing each command followed by the Enter key After typing all the commands press Enter to go to a blank line and type Ctrl D Alternatively a shell script can be entered at the prompt pressing Enter after each line in the script and typing Ctrl D on a blank line to exit If a script is entered the shell used is the shell set in the user s SHELL environment the user s login shell or bin sh whichever is found first As soon as the load average is below 0 8 the set of commands or script is executed If the set of commands or script tries to display information to standard out the output is emailed to the user Use the command atq to view pending jobs Refer to Section 37 2 3 Viewing Pending Jobs for more information Usage of the bat ch command can be restricted Refer to Sect
43. 3 Select Ethernet connection from the Device Type list and click Forward 4 If you have already added the network interface card to the hardware list select it from the Ethernet card list Otherwise select Other Ethernet Card to add the hardware device Note The installation program detects supported Ethernet devices and prompts you to configure them If you configured any Ethernet devices during the installation they are displayed in the hardware list on the Hardware tab 5 If you selected Other Ethernet Card the Select Ethernet Adapter window appears Select the manufacturer and model of the Ethernet card Select the device name If this is the system s first Ethernet card select eth0 as the device name if this is the second Ethernet card select eth1 and so on The Network Administration Tool also allows you to configure the resources for the NIC Click Forward to continue 6 In the Configure Network Settings window as shown in Figure 19 2 choose between DHCP and a static IP address If the device receives a different IP address each time the network is started do not specify a hostname Click Forward to continue 7 Click Apply on the Create Ethernet Device page Chapter 19 Network Configuration 125 Configure Network Settings Automatically obtain IP address settings with dhcp Y DHCP Settings Hostname optional v Automatically obtain DNS information from provider CO Sta
44. DHCP client refer to Chapter 19 Network Configuration for details on using Network Administration Tool to configure a network interface to use DHCP 1 Kudzu is a hardware probing tool run at system boot time to determine what hardware has been added or removed from the system Chapter 25 Dynamic Host Configuration Protocol DHCP 187 25 4 Additional Resources For configuration options not covered here refer to the following resources 25 4 1 Installed Documentation dhcpd man page describes how the DHCP daemon works dhcpd conf man page explains how to configure the DHCP configuration file includes some examples e dhcpd leases man page explains how to configure the DHCP leases file includes some ex amples dhcp options man page explains the syntax for declaring DHCP options in dhcpd conf includes some examples dhcrelay man page explains the DHCP Relay Agent and its configuration options 188 Chapter 25 Dynamic Host Configuration Protocol DHCP redhat Chapter 26 Apache HTTP Server Configuration Red Hat Enterprise Linux provides version 2 0 of the Apache HTTP Server If you want to migrate an existing configuration file by hand refer to the migration guide at usr share doc httpd lt ver gt migration html or the Red Hat Enterprise Linux Reference Guide for details If you configured the Apache HTTP Server with the HTTP Configuration Tool in previous versions of Red Hat Enterpris
45. Do not append the number with MB grow Tells the partition to grow to fill available space if any or up to the maximum size setting Chapter 9 Kickstart Installations 51 maxsize The maximum partition size in megabytes when the partition is set to grow Specify an integer value here and do not append the number with MB noformat Tells the installation program not to format the partition for use with the onpart com mand onpart or usepart Put the partition on the already existing device For example partition home onpart hda1 will put home on dev hda1 which must already exist ondisk or ondrive Forces the partition to be created on a particular disk For example ondisk sdb will put the partition on the second SCSI disk on the system asprimary Forces automatic allocation of the partition as a primary partition or the partitioning will fail type replaced by fstype This option is no longer available Use fstype fstype Sets the file system type for the partition Valid values are ext 2 ext 3 swap and vfat start Specifies the starting cylinder for the partition It requires that a drive be specified with ondisk or ondrive It also requires that the ending cylinder be specified with end or the partition size be specified with size end Specifies the ending cylinder for the partition It requires that the starting cylinder be speci fied
46. HTTPS the SSL version of HTTP FTP The FTP protocol is used to transfer files between machines on a network If you plan on making your FTP server publicly available enable this option The vsftpd package must be installed for this option to be useful SSH Secure Shell SSH is a suite of tools for logging into and executing commands on a remote machine To allow remote access to the machine via ssh enable this option The openssh server package must be installed to access your machine remotely using SSH tools Telnet Telnet is a protocol for logging into remote machines Telnet communications are unencrypted and provide no security from network snooping Allowing incoming Telnet access is not rec ommended To allow inbound Telnet access you must have the telnet server package installed Mail SMTP To allow incoming mail delivery through your firewall so that remote hosts can connect di rectly to your machine to deliver mail enable this option You do not need to enable this if Chapter 20 Basic Firewall Configuration 149 you collect your mail from your ISP s server using POP3 or IMAP or if you use a tool such as fetchmail Note that an improperly configured SMTP server can allow remote machines to use your server to send spam Click OK to save the changed and enable or disable the firewall If Enable firewall was selected the options selected are translated to iptables commands and written to the etc sysconfig iptable
47. Installed Documentation e acl man page Description of ACLs getfacl man page Discusses how to get file access control lists e setfacl man page Explains how to set file access control lists e star man page Explains more about the star utility and its many options 8 7 2 Useful Websites http acl bestbits at Website for ACLs Chapter 8 Access Control Lists 35 http www fokus gmd de research cc glone employees joerg schilling private star html Website for the star utility 36 Chapter 8 Access Control Lists ll Installation Related Information The Red Hat Enterprise Linux Installation Guide discusses the installation of Red Hat Enterprise Linux and some basic post installation troubleshooting However advanced installation options are covered in this manual This part provides instructions for kickstart an automated installation tech nique system recovery modes how to boot your system if it does not boot in the normal runlevel how to configure RAID during installation and how to configure LVM during installation Use this part in conjunction with the Red Hat Enterprise Linux Installation Guide to perform any of these advanced installation tasks Table of Contents 9 Kickstart Installations 10 Kickstart Configurator 11 Basic System Recovery 12 Software RAID Configuration 13 LVM Configuration 14 PXE Network Installations csscssssssssssssssssssssssssssssssssescssesess
48. Japanese fonts to a non Japanese printer Extra time is required to perform this action Do not choose it unless problems printing the correct fonts exist 260 Chapter 36 Printer Configuration Also select this option if the printer can not handle PostScript level 3 This option converts it to PostScript level 1 GhostScript pre filtering allows you to select No pre filtering Convert to PS level 1 or Convert to PS level 2 in case the printer can not handle certain PostScript levels This option is only available if the PostScript driver is used Page Size allows the paper size to be selected The options include US Letter US Legal A3 and A4 Effective Filter Locale defaults to C If Japanese characters are being printed select ja_JP Oth erwise accept the default of C Media Source defaults to Printer default Change this option to use paper from a different tray To modify the driver options click OK to return to the main window Click Apply to save the change and restart the printer daemon 36 10 Saving the Configuration File When the printer configuration is saved using the Printer Configuration Tool the application creates its own configuration file that is used to create the files in the etc cups directory You can use the command line options to save or restore the Printer Configuration Tool file If the etc cups directory is saved and restored to the same locations the printer configuration is not rest
49. Red Hat Control Network program to activate it after boot time To start it select Main Menu Button on the Panel gt System Tools gt Network Device Control or type the command redhat control network Qa Sh The following network interfaces are configured in the active profile status Device Nickname Activate N Active etho etho Inactive ethl ethl Deactivate Configure Info _ Close Figure 19 18 Activating Devices To activate a device select it from the list and click the Activate button To stop the device select it from the list and click Deactivate If more than one network profile is configured they are listed in the interface and can be activated Refer to Section 19 12 Working with Profiles for details 19 12 Working with Profiles Multiple logical network devices can be created for each physical hardware device For example if you have one Ethernet card in your system ethO you can create logical network devices with different nicknames and different configuration options all to be specifically associated with eth0 Logical network devices are different from device aliases Logical network devices associated with the same physical device must exist in different profiles and cannot be activated simultaneously Device aliases are also associated with the same physical hardware device but device aliases associated with the same physical hardware can be ac
50. See group configuration floppy use of 230 H hardware viewing 297 Hardware Browser 297 Hardware RAID See RAID hesiod 220 hotplug 28 HTTP Configuration Tool directives See HTTP directives error log 192 modules 189 321 transfer log 192 HTTP directives DirectoryIndex 191 ErrorDocument 192 ErrorLog 193 Group 200 HostnameLookups 193 KeepAlive 201 KeepAliveTimeout 201 Listen 190 LogFormat 193 LogLevel 193 MaxClients 200 MaxKeepAliveRequests 201 Options 192 ServerAdmin 190 ServerName 190 TimeOut 200 TransferLog 193 User 199 httpd 189 hwbrowser 297 information about your system 293 insmod 286 installation kickstart See kickstart installations LVM 87 PXE See PXE installations software RAID 83 Internet connection See network configuration introduction i IPsec host to host 141 network to network 142 ipsec tools 141 143 iptables 149 ISDN connection See network configuration 322 K Kerberos 221 kernel building 315 custom 315 downloading 279 large memory support 277 modular 315 modules 285 multiple processor support 277 upgrading 277 kernel modules listing 285 loading 286 unload 286 keyboard configuring 233 Keyboard Configuration Tool 233 kickstart how the file is found 60 Kickstart Configurator 63 opost script 77 pre script 76 authentication options 71 basic options 63 boot loader 66 boot loader options 66 firew
51. Sendmail and Postfix If both are installed sendmail is the default MTA The Mail Transport Agent Switcher allows for the selection of either sendmail or postfix as the default MTA for the system The redhat switch mail RPM package must be installed to use the text based version of the Mail Transport Agent Switcher program If you want to use the graphical version the redhat switch mail gnome package must also be installed For more information on installing RPM packages refer to Part III Package Management To start the Mail Transport Agent Switcher select Main Menu Button on the Panel gt Sys tem Tools gt More System Tools gt Mail Transport Agent Switcher or type the command redhat switch mail at a shell prompt for example in an XTerm or GNOME terminal The program automatically detect if the X Window System is running If it is running the program starts in graphical mode as shown in Figure 41 1 If X is not detected it starts in text mode To force Mail Transport Agent Switcher to run in text mode use the command redhat switch mail nox The Mail Transport Agent Switcher is a tool which enables fi users to easily switch between various Mail Transport Agent F that they have installed Please choose your Mail transport agent Available Mail Transport Agent Sendmail O Postfix 2 Cancel OK Figure 41 1 Mail Transport Agent Switcher If you select OK to change the MTA th
52. The optional GECOS information is left blank The home directory for juan is set to home juan The default shell is set to bin bash 246 Chapter 35 User and Group Configuration 2 A new line for juan is created in etc shadow The line has the following characteristics It begins with the username juan Two exclamation points appear in the password field of the etc shadow file which locks the account Note If an encrypted password is passed using the p flag it is placed in the etc shadow file on the new line for the user The password is set to never expire 3 A new line for a group named juan is created in etc group A group with the same name as a user is called a user private group For more information on user private groups refer to Section 35 1 Adding a New User The line created in etc group has the following characteristics It begins with the group name juan An x appears in the password field indicating that the system is using shadow group pass words The GID matches the one listed for user juan in etc passwd 4 A new line for a group named juan is created in etc gshadow The line has the following characteristics It begins with the group name juan e An exclamation point appears in the password field of the etc gshadow file which locks the group All other fields are blank 5 A directory for user juan is created in the home directory This directory is
53. The steps for creating an ext3 file system are as follows 1 Create the partition using parted or fdisk 2 Format the partition with the ext3 file system using mkfs 3 Label the partition using e21abel 4 Create the mount point 5 Add the partition to etc fstab Refer to Chapter 5 Managing Disk Storage for information on performing these steps 1 3 Converting to an ext3 File System The tune2fs program can add a journal to an existing ext2 file system without altering the data already on the partition If the file system is already mounted while it is being transitioned the journal will be visible as the file journal in the root directory of the file system If the file system is not mounted the journal will be hidden and will not appear in the file system at all To convert an ext2 file system to ext3 log in as root and type sbin tune2fs j dev hdbx In the above command replace dev hdb with the device name and X with the partition number After doing this be certain to change the partition type from ext2 to ext3 in etc fstab If you are transitioning your root file system you will have to use an initrd image or RAM disk to boot To create this run the mkinitrd program For information on using the mkinitrd command type man mkinitrd Also make sure your GRUB or LILO configuration loads the initrd If you fail to make this change the system will still boot but the file system will be mounted as ext2 instead of ex
54. To start the Network Booting Tool from the desktop go to the Main Menu Button on the Panel gt System Settings gt Server Settings gt Network Booting Service Or type the command redhat config netboot at a shell prompt for example in an XTerm or a GNOME terminal If starting the Network Booting Tool for the first time select Network Install from the First Time Druid Otherwise select Configure gt Network Installation from the pull down menu and then click Add The dialog in Figure 14 1 is displayed 92 Chapter 14 PXE Network Installations Operating system identifier rhel 3 as Description RHEL 3 AS Select protocol for installation NFS Software _ Server server example com Location misc rhel 3 as Anonymous FTP User Password 3 Cancel OK Figure 14 1 Network Installation Setup Provide the following information Operating system identifier Provide a unique name using one word to identify the Red Hat Enterprise Linux version and variant It is used as the directory name in the tftpboot linux install1 directory e Description Provide a brief description of the Red Hat Enterprise Linux version and variant Select protocol for installation Select NFS FTP or HTTP as the network installation type depending on which one was configured previously If FTP is selected and anonymous FTP is not being used uncheck Anonymous FTP
55. Window System skip to Section 22 3 4 5 Configuring ssh agent 22 3 4 2 Generating a DSA Key Pair for Version 2 Use the following steps to generate a DSA key pair for version 2 of the SSH Protocol a To generate a DSA key pair to work with version 2 of the protocol type the following command at a shell prompt ssh keygen t dsa Accept the default file location of ssh id_dsa Enter a passphrase different from your account password and confirm it by entering it again A passphrase is a string of words and characters used to authenticate a user Passphrases differ from passwords in that you can use spaces or tabs in the passphrase Passphrases are generally longer than passwords because they are usually phrases instead of a single word The public key is written to ssh id_dsa pub The private key is written to ssh id_dsaa It is important never to give anyone the private key Change the permissions of the ssh directory with the following command chmod 755 ssh Copy the contents of ssh id_dsa pub to ssh authorized_keys on the machine to which you want to connect If the file ssh authorized_keys exist append the contents of the file ssh id_dsa pub to the file ssh authorized_keys on the other machine Change the permissions of the authorized_keys file using the following command chmod 644 ssh authorized_keys If you are running GNOME skip to Section 22 3 4 4 Configuring ssh agent wit
56. X Window System is not running a small version of X is started to run the program After changing any of the settings log out of the graphical desktop and log back in to enable the changes 34 1 Display Settings The Display tab allows users to change the resolution and color depth The display of a monitor consists of tiny dots called pixels The number of pixels displayed at one time is called the resolution For example the resolution 1024x768 means that 1024 horizontal pixels are used and 768 vertical pixels are used The higher the resolution numbers the more images the monitor can display at one time For example the higher the resolution the smaller the desktop icons appear and the more icons it takes to fill the entire desktop The color depth of the display determines how many possible colors are displayed The higher the color depth the more contrast between colors Display Advanced ViewSonic G773 with S3 ViIRGE generic Resolution Color Depth 1024x768 x Thousands of Colors T 3 Cancel 2 OK Figure 34 1 Display Settings 34 2 Advanced Settings When the application is started it probes the monitor and video card If the hardware is probed prop erly the information for it is shown on the Advanced tab as shown in Figure 34 2 238 Chapter 34 X Window System Configuration D
57. Zone Enter the domain name for the slave zone in the Domain name text area A new window appears as shown in Figure 28 4 with the following options Name The domain name that was entered in the previous window Masters List The nameservers from which the slave zone retrieves its data Each value must be a valid IP address Only numbers and periods can be entered in the text area File Name File name of the DNS database file in var named Name slave example com Masters List File Name slave example com zone 3 Cancel OK Figure 28 4 Adding a Slave Zone After configuring the slave zone click OK to return to the main window as shown in Figure 28 1 Click Save to write the etc named conf configuration file and have the daemon reload the configuration files The configuration creates an entry similar to the following in etc named conf zone Slave example com type slave file slave example com zone masters L232 3 c49 Me Me The configuration file var named slave example com zone is created by the named service when it downloads the zone data from the master server s 218 Chapter 28 BIND Configuration redhat Chapter 29 Authentication Configuration When a user logs in to a Red Hat Enterprise Linux system the username and password combination must be verified or authenticated as a valid and active user Sometimes the information to ver
58. a dynamic IP address to a system within a subnet modify Example 25 4 with your values It declares a default lease time maximum lease time and network configuration values for the clients This example assigns IP addresses in the range 192 168 1 10 and 192 168 1 100 to client systems default lease time 600 max lease time 7200 option subnet mask 255 255 255 0 option broadcast address 192 168 1 255 option routers 192 168 1 254 option domain name servers 192 168 1 1 192 168 1 2 option domain name example com subnet 192 168 1 0 netmask 255 255 255 0 range 192 168 1 10 192 168 1 100 Example 25 4 Range Parameter To assign an IP address to a client based on the MAC address of the network interface card use the hardware ethernet parameter within a host declaration As demonstrated in Example 184 Chapter 25 Dynamic Host Configuration Protocol DHCP 25 5 the host apex declaration specifies that the network interface card with the MAC address 00 A0 78 8E 9E AA always receives the IP address 192 168 1 4 Notice that the optional parameter hostname can be used to assign a host name to the client host apex option host name apex example com hardware ethernet 00 A0 78 8E 9E AA fixed address 192 168 1 4 Example 25 5 Static IP Address using DHCP Om The sample configuration file provided can be used as a starting point Custom configuration options can be added to it To copy it to the proper location
59. a printer attached to another Red Hat Enterprise Linux system running CUPS on the network Networked UNIX LPD a printer attached to a different UNIX system that can be accessed over a TCP IP network for example a printer attached to another Red Hat Enterprise Linux system running LPD on the network 250 Chapter 36 Printer Configuration Networked Windows SMB a printer attached to a different system which is sharing a printer over a SMB network for example a printer attached to a Microsoft Windows machine Networked Novell NCP a printer attached to a different system which uses Novell s NetWare network technology Networked JetDirect a printer connected directly to the network through HP JetDirect instead of to a computer Important If you add a new print queue or modify an existing one you must apply the changes to them to take effect Clicking the Apply button saves any changes that you have made and restarts the printer daemon The changes are not written to the configuration file until the printer daemon is restarted Alternatively you can choose Action gt Apply 36 1 Adding a Local Printer To add a local printer such as one attached through a parallel port or USB port on your computer click the New button in the main Printer Configuration Tool window to display the window in Figure 36 2 Click Forward to proceed Add a new print queue On the following screens you will
60. an Installation Boot CD ROM section in the Red Hat Enterprise Linux Installation Guide for instruction on creating a boot CD ROM however before making the file iso image file copy the ks cfg kickstart file to the isolinux directory 9 8 3 Making the Kickstart File Available on the Network Network installations using kickstart are quite common because system administrators can easily au tomate the installation on many networked computers quickly and painlessly In general the approach most commonly used is for the administrator to have both a BOOTP DHCP server and an NFS server on the local network The BOOTP DHCP server is used to give the client system its networking infor mation while the actual files used during the installation are served by the NFS server Often these two servers run on the same physical machine but they are not required to To perform a network based kickstart installation you must have a BOOTP DHCP server on your network and it must include configuration information for the machine on which you are attempting to install Red Hat Enterprise Linux The BOOTP DHCP server will provide the client with its networking information as well as the location of the kickstart file If a kickstart file is specified by the BOOTP DHCP server the client system will attempt an NFS mount of the file s path and will copy the specified file to the client using it as the kickstart file The exact settings required vary depending o
61. and openssh packages installed on the client machine 22 3 1 Using the ssh Command The ssh command is a secure replacement for the rlogin rsh and telnet commands It allows you to log in to a remote machine as well as execute commands on a remote machine Logging in to a remote machine with ssh is similar to using telnet To log in to a remote machine named penguin example net type the following command at a shell prompt ssh penguin example net The first time you ssh to a remote machine you will see a message similar to the following The authenticity of host penguin example net can t be established DSA key fingerprint is 94 68 3a 3a bc f3 9a 9b 01 5d b3 07 38 e2 11 0c Are you sure you want to continue connecting yes no Type yes to continue This will add the server to your list of known hosts as seen in the following message Warning Permanently added penguin example net RSA to the list of known hosts Next you will see a prompt asking for your password for the remote machine After entering your password you will be at a shell prompt for the remote machine If you do not specify a username the username that you are logged in as on the local client machine is passed to the remote machine If you want to specify a different username use the following command ssh username penguin example net You can also use the syntax ssh 1 username penguin example net The ssh command can be used to execute a com
62. and Stopping OProfile ssssssssssssssssssrsrssrssssreststssresrnrenenrsssnresrsrsnres 43 4 Saving Data 43 5 Analyzing the Data 43 6 Understanding d v profile iniennounonniiiuen nanana 43 7 Example Usage eee 43 8 Graphical Interface i 43 9 Additional RESOULCES iire csesetesseseeseseesseseaescsesesecseesaesesseseasseseneeaeaes 312 VIT Appendixes ccsccccssssssseccsssssssssccsssssssssseesesssssesecsesessssssssssesssesessasssssesessasesesessevasesssessssesessseees 313 As Building a Custom Kernel 3 0 croni ou naaa RABAR ARAA 315 A 1 Preparing to Build A 2 Building the Kernel A 3 Additional Resources redhat Introduction Welcome to the Red Hat Enterprise Linux System Administration Guide The Red Hat Enterprise Linux System Administration Guide contains information on how to customize your Red Hat Enterprise Linux system to fit your needs If you are looking for a step by step task oriented guide for configuring and customizing your system this is the manual for you This manual discusses many intermediate topics such as the following Setting up a network interface card NIC Performing a Kickstart installation Configuring Samba shares Managing your software with RPM e Determining information about your system Upgrading your kernel This manual is divided into the following main categories Installation Related Reference Network Related Reference System Conf
63. and provide a valid username and password combination Server Provide the IP address or domain name of the NFS FTP or HTTP server Location Provide the directory shared by the network server If FTP or HTTP was selected the directory must be relative to the default directory for the FTP server or the document root for the HTTP server For all network installations the directory provided must contain the RedHat directory of the installation tree After clicking OK the initrd img and vmlinuz files necessary to boot the installation program are transfered from images pxeboot in the provided installation tree to tftpboot linux install lt os identifier gt on the tftp server the one you are running the Network Booting Tool on 14 2 1 Command Line Configuration If the network server is not running X the pxeos command line utility which is part of the redhat config netboot package can be used to configure the tftp server files as described in Section 14 4 Starting the tftp Server pxeos a i lt description gt p lt NFS HTTP FTP gt D 0 s client example com L lt net location gt lt os identifer gt The following list explains the options e a Specifies that an OS instance is being added to the PXE configuration e i lt description gt Replace lt description gt with a description of the OS instance This corresponds to the Description field in Figure 14 1 p lt NFSIHTTPIFTP gt
64. any of these files and if Options Indexes is set for that directory the server will generate and return a list in HTML format of the subdirectories and files in the directory Use the Error Code section to configure Apache HTTP Server to redirect the client to a local or external URL in the event of a problem or error This option corresponds to the ErrorDocument directive If a problem or error occurs when a client tries to connect to the Apache HTTP Server the default action is to display the short error message shown in the Error Code column To override this default configuration select the error code and click the Edit button Choose Default to display the default short error message Choose URL to redirect the client to an external URL and enter a complete URL including the http in the Location field Choose File to redirect the client to an internal URL and enter a file location under the document root for the Web server The location must begin the a slash and be relative to the Document Root For example to redirect a 404 Not Found error code to a webpage that you created in a file called 404 html copy 404 html to DocumentRoot error 404 html In this case DocumentRoot is the Document Root directory that you have defined the default is var www htm1 If the Document Root is left as the default location the file should be copied to var www error 404 html Then choose File as the Behavior for 404 Not Found error code and en
65. apply to them For example if a system included an SMC EtherPower 10 PCI network adapter the module configu ration file contains the following line alias eth0 tulip If a second network card is added to the system and is identical to the first card add the following line to etc modules conf alias ethl tulip See the Red Hat Enterprise Linux Reference Guide for an alphabetical list of kernel modules and the hardware supported by the modules 40 1 Kernel Module Utilities A group of commands for managing kernel modules is available if the modut ils package is installed Use these commands to determine if a module has been loaded successfully or when trying different modules for a piece of new hardware The command sbin 1smod displays a list of currently loaded modules For example Module Size Used by Not tainted iptable_filter 2412 0 autoclean unused ip_tables 15864 1 iptable_filter nfs 84632 1 autoclean lockd 59536 1 autoclean nfs sunrpc 87452 1 autoclean nfs lockd soundcore 7044 0 autoclean ide cd 35836 0 autoclean cdrom 34144 0 autoclean ide cd parport_pc 19204 1 autoclean 286 Chapter 40 Kernel Modules lp 9188 0 autoclean parport 39072 autoclean parport_pc lp autofs 13692 0 autoclean unused e100 62148 microcode 5184 0 autoclean keybdev 2976 0 unused mousedev 5656 hid 22308 0 unused input 6208 0 keybdev mousedev hid usb uhci 27468 0 unused usbcore 8275
66. arpa zone Primary Nameserver SOA Serial Number ja Set Time Settings Nameservers Add f Edit is Delete Reverse Address Table Address Host or Domain Add Pa Edit amp Delete W 38 Cancel OK Figure 28 3 Adding a Reverse Master Zone A Primary Nameserver SOA must be specified and at least one nameserver record must be speci fied by clicking the Add button in the Nameservers section After configuring the Reverse Master Zone click OK to return to the main window as shown in Figure 28 1 From the pulldown menu click Save to write the etc named conf configuration file write all the individual zone files in the var named directory and have the daemon reload the configuration files The configuration creates an entry similar to the following in etc named conf zone 10 168 192 in addr arpa type master file 10 168 192 in addr arpa zone i It also creates the file var named 10 168 192 in addr arpa zone with the following infor mation TTL 86400 IN SOA ns example com root localhost 2 serial 28800 refresh 7200 retry 604800 expire 86400 ttk Chapter 28 BIND Configuration 217 IN NS ns2 example com 1 IN PIR one example com 2 IN PTR two example com 28 3 Adding a Slave Zone To add a slave zone also known as a secondary master click the New button and select Slave
67. commas of which the user is a member The groups must exist prior to being specified here Create a system account with a UID less than 500 and without a home directory The password encrypted with crypt User s login shell which defaults to bin bash User ID for the user which must be unique and greater than 499 Table 35 1 useradd Command Line Options Create the home directory if it does not exist 35 5 2 Adding a Group To add a group to the system use the command groupadd groupadd lt group name gt Command line options for groupadd are detailed in Table 35 2 Group ID for the group which must be unique and greater than 499 Create a system group with a GID less than 500 f Exit with an error if the group already exists The group is not altered If g and f are specified but the group already exists the g option is ignored Table 35 2 groupadd Command Line Options 35 5 3 Password Aging For security reasons it is a good practice to require users to change their passwords periodically This can be done when adding or editing a user on the Password Info tab of the User Manager To configure password expiration for a user from a shell prompt use the chage command followed by an option from Table 35 3 followed by the username of the user 244 Chapter 35 User and Group Configuration ion Shadow passwords must be enabled to use the chage command Option Description o m days Specify
68. defined within the virtual host settings the default setting is used For example you can define a Webmaster email address in the Main tab and not define individual email addresses for each virtual host The HTTP Configuration Tool includes a default virtual host as shown in Figure 26 8 Chapter 26 Apache HTTP Server Configuration 197 Main Virtual Hosts Server Performance Tuning Virtual Hosts Name Address Add Default Virtual Host Default virtual host Edit Delete Edit Default Settings 2 OK 3 Cancel T Heip Figure 26 8 Virtual Hosts http httpd apache org docs 2 0 vhosts and the Apache HTTP Server documentation on your ma chine provides more information about virtual hosts 26 3 1 Adding and Editing a Virtual Host To add a virtual host click the Virtual Hosts tab and then click the Add button You can also edit a virtual host by selecting it in the list and clicking the Edit button 26 3 1 1 General Options The General Options settings only apply to the virtual host that you are configuring Set the name of the virtual host in the Virtual Host Name text area This name is used by HTTP Configuration Tool to distinguish between virtual hosts Set the Document Root Directory value to the directory that contains the root document such as index html for the virtual host This option corresponds to the Document
69. different times with multiple cron tasks Refer to Chapter 37 Automated Tasks for more information about configuring cron 6 2 3 Enabling and Disabling It is possible to disable quotas without setting them to be 0 To turn all user and group quotas off use the following command quotaoff vaug If neither the u or g options are specified only the user quotas are disabled If only g is specified only group quotas are disabled To enable quotas again use the quot aon command with the same options For example to enable user and group quotas for all file systems quotaon vaug To enable quotas for a specific file system such as home quotaon vug home If neither the u or g options are specified only the user quotas are enabled If only g is specified only group quotas are enabled 6 3 Additional Resources For more information on disk quotas refer to the following resources 6 3 1 Installed Documentation e The quotacheck edquota repquota quota quotaon and quotaof f man pages 26 Chapter 6 Implementing Disk Quotas 6 3 2 Related Books Red Hat Enterprise Linux Introduction to System Administration Red Hat Inc Available at http www redhat com docs and on the Documentation CD this manual contains background in formation on storage management including disk quotas for new Red Hat Enterprise Linux system administrators redhat Chapter 7 User Defined Device Names The dev dire
70. directive sets the number of seconds your server will wait for a subsequent request after a request has been served before it closes the connection Once a request has been received the Connection Timeout value applies instead Setting the Persistent Connections to a high value may cause a server to slow down depending on how many users are trying to connect to it The higher the number the more server processes waiting for another connection from the last client that connected to it 26 6 Saving Your Settings If you do not want to save your Apache HTTP Server configuration settings click the Cancel button in the bottom right corner of the HTTP Configuration Tool window You will be prompted to confirm this decision If you click Yes to confirm this choice your settings will not be saved If you want to save your Apache HTTP Server configuration settings click the OK button in the bottom right corner of the HTTP Configuration Tool window A dialog window will appear If you answer Yes your settings will be saved in etc httpd conf httpd conf Remember that your original configuration file will be overwritten If this is the first time that you have used the HTTP Configuration Tool you will see a dialog window warning you that the configuration file has been manually modified If the HTTP Configuration Tool detects that the httpd conf configuration file has been manually modified it will save the manually modified file as etc httpd con
71. editing configuration files If you try to start other popular editors such as emacs pico or vi the joe editor will be started 11 3 Booting into Single User Mode One of the advantages of single user mode is that you do not need a boot diskette or CD ROM however it does not give you the option to mount the file systems as read only or not mount them at all If your system boots but does not allow you to log in when it has completed booting try single user mode In single user mode your computer boots to runlevel 1 Your local file systems are mounted but your network is not activated You have a usable system maintenance shell Unlike rescue mode single user mode automatically tries to mount your file system do not use single user mode if your file system can not be mounted successfully You can not use single user mode if the runlevel 1 configuration on your system is corrupted On an x86 system using GRUB as the boot loader use the following steps to boot into single user mode 82 Chapter 11 Basic System Recovery 1 If you have a GRUB password configured type p and enter the password 2 Select Red Hat Enterprise Linux with the version of the kernel that you wish to boot and type a to append the line 3 Go to the end of the line and type single as a separate word press the Spacebar and then type single Press Enter to exit edit mode 4 Back at the GRUB screen type b to boot into single user mode On an x8
72. etc sysconfig dhcpd include p lt portnum gt Specify the udp port number on which dhcpd should listen The default is port 67 The DHCP server transmits responses to the DHCP clients at a port number one greater than the udp port specified For example if the default port 67 is used the server listens on port 67 for requests and responses to the client on port 68 If a port is specified here and the DHCP relay agent is used the same port on which the DHCP relay agent should listen must be specified Refer to Section 25 2 4 DHCP Relay Agent for details f Run the daemon as a foreground process This is mostly used for debugging d Log the DHCP server daemon to the standard error descriptor This is mostly used for de bugging If this is not specified the log is written to var log messages e cf lt filename gt Specify the location of the configuration file The default location is etc dhepd conf e 1f lt filename gt Specify the location of the lease database file If a lease database file already exists it is very important that the same file be used every time the DHCP server is started It is strongly recommended that this option only be used for debugging purposes on non production machines The default location is var lib dhcp dhcpd leases q Do not print the entire copyright message when starting the daemon 25 2 4 DHCP Relay Agent The DHCP Relay Agent dhcrelay allows for the relay
73. exception of the boot partition The boot partition can not be on a logical volume group because the boot loader can not read it If the root partition is on a logical volume create a separate boot partition which is not a part of a volume group Since a physical volume can not span over more than one drive to span over more than one drive create one or more physical volumes per drive Physical Volume Physical Volume Physical Volume boot 9 1 GB 9 1 GB 9 1 GB 75 MB ext3 Logical Volume Group 9 1 GB x 3 75 MB we _ Figure 4 1 Logical Volume Group The logical volume group is divided into logical volumes which are assigned mount points such as home and and file system types such as ext3 When partitions reach their full capacity free space from the logical volume group can be added to the logical volume to increase the size of the partition When a new hard drive is added to the system it can be added to the logical volume group and the logical volumes that are the partitions can be expanded 14 Chapter 4 Logical Volume Manager LVM Logical Volume Group 9 1 GB x 3 75 MB Logical Volume Logical Volume Free Space home 20 GB 2GB 5 GB Figure 4 2 Logical Volumes On the other hand if a system is partitioned with the ext3 file system the hard drive is divided into partitions of defined sizes If a partition becomes full it is not easy to expand the size of the partition Even if the partition
74. fix security and other bugs 1 Y Updated mm packages available o Updated KDE packages fix security issues 1 Updatedy er packages fix vulnerability 0 Updated wget packages fix directory traversal bug 2 Updated xinetd packages fix denial of service vuinerability 1 Updated apache httpd and mod_ss packages available 1 New samba packages av ji security vulnerability 1 New kemel fixes local denial of s 3 10 of 17 relevant errata shown View All Relevant Errata Legal statement Privacy statement redhat com Ad bug report Figure 18 1 Your RHN Red Hat Network saves users time because they receive email when updated packages are released Users do not have to search the Web for updated packages or security alerts By default Red Hat Network installs the packages as well Users do not have to learn how to use RPM or worry about resolving software package dependencies RHN does it all Red Hat Network features include Errata Alerts learn when Security Alerts Bug Fix Alerts and Enhancement Alerts are issued for all the systems in your network 118 Chapter 18 Red Hat Network redhat NETWORK tammyfox Sign Out All Your RHN Systems Systems I searen GG Errata Relevant to Your Systems Q Software Schedule Users Advanced Search ae FHSA 2002 293 Updated Fetchmall packages fix security vulnerability Q Security FHSA 2002228 Updated Net SNMP packag
75. for example msdos for x86 and gpt for Itanium select Initialize the disk label if you are installing on a brand new hard drive 10 4 1 Creating Partitions To create a partition click the Add button The Partition Options window shown in Figure 10 5 appears Choose the mount point file system type and partition size for the new partition Optionally you can also choose from the following In the Additional Size Options section choose to make the partition a fixed size up to a chosen size or fill the remaining space on the hard drive If you selected swap as the file system type you can select to have the installation program create the swap partition with the recommended size instead of specifying a size e Force the partition to be created as a primary partition e Create the partition on a specific hard drive For example to make the partition on the first IDE hard disk dev hda specify hda as the drive Do not include dev in the drive name Use an existing partition For example to make the partition on the first partition on the first IDE hard disk dev hda1 specify hda1 as the partition Do not include dev in the partition name Format the partition as the chosen file system type 68 Mount Point File System Type ext3 ap i Size MB 1 Additional Size Options Fixed size O Grow to maximum of MB 1 O Fill all unused space on disk LJ Use recommended swap size
76. group of users working on the same project can have access to the files for that project using a shared directory of the NFS file system commonly known as an NFS share mounted in the directory mypro ject To access the shared files the user goes into the mypro ject directory on his machine There are no passwords to enter or special commands to remember Users work as if the directory is on their local machines 23 2 Mounting NFS File Systems Use the mount command to mount a shared NFS directory from another machine mount shadowman example com misc export misc local waming The mount point directory on local machine misc loca1 in the above example must exist In this command shadowman example comis the hostname of the NFS file server misc export is the directory that shadowman is exporting and misc local is the location to mount the file system on the local machine After the mount command runs and if the client has proper permis sions from the shadowman example com NFS server the client user can execute the command 1s misc local to display a listing of the files in misc export on shadowman example com 23 2 1 Mounting NFS File Systems using etc fstab An alternate way to mount an NFS share from another machine is to add a line to the etc fstab file The line must state the hostname of the NFS server the directory on the server being exported and the directory on the local machine where the NFS share is to be moun
77. installed for RPM verification execute the command rpm qa gpg pubkey For the Red Hat key the output includes gpg pubkey db42a60e 37ea5438 To display details about a specific key use rpm qi followed by the output from the previous com mand rpm qi gpg pubkey db42a60e 37ea5438 16 3 2 Verifying Signature of Packages To check the GnuPG signature of an RPM file after importing the builder s GnuPG key use the following command replace lt rpm file gt with filename of the RPM package rpm K lt rpm file gt If all goes well the following message is displayed md5 gpg OK That means that the signature of the package has been verified and that it is not corrupt 16 4 Impressing Your Friends with RPM RPM is a useful tool for both managing your system and diagnosing and fixing problems The best way to make sense of all of its options is to look at some examples Perhaps you have deleted some files by accident but you are not sure what you deleted To verify your entire system and see what might be missing you could try the following command rpm Va If some files are missing or appear to have been corrupted you should probably either re install the package or uninstall then re install the package At some point you might see a file that you do not recognize To find out which package owns it you would enter rpm qf usr X11R6 bin ghostview The output would look like the following gv 3 5 8 22
78. is moved to another hard drive the original hard drive space has to be reallocated as a different partition or not used LVM support must be compiled into the kernel The default Red Hat kernel is compiled with LVM support To learn how to configure LVM during the installation process refer to Chapter 13 LVM Configuration 4 2 Additional Resources Use these sources to learn more about LVM 4 2 1 Installed Documentation rpm qd lvm This command shows all the documentation available from the 1vm package including man pages 4 2 2 Useful Websites http www sistina com products_lvm htm LVM webpage which contains an overview link to the mailing lists and more http tldp org HOWTO LVM HOWTO LVM HOWTO from the Linux Documentation Project redhat Chapter 5 Managing Disk Storage Many users need to view the existing partition table change the size of the partitions remove parti tions or add partitions from free space or additional hard drives The utility partea allows users to perform these tasks This chapter discusses how to use parted to perform file system tasks If you want to view the system s disk space usage or monitor the disk space usage refer to Section 42 3 File Systems You must have the parted package installed to use the parted utility To start parted at a shell prompt as root type the command parted dev hdb where dev hdb is the device name for the drive you want to co
79. kernel version that is returned 316 Appendix A Building a Custom Kernel 1 Open a shell prompt and change to the directory usr src linux 2 4 All commands from this point forward must be executed from this directory 2 It is important that kernel build starts with the source tree in a known condition Therefore it is recommended that the command make mrproper is issued first to remove any configuration files along with the remains of any previous builds that may be scattered around the source tree If an existing configuration file already exists as the file usr src linux 2 4 config back it up to a different directory before running this command and copy it back afterward 3 It is recommended that the configuration of the default Red Hat Enterprise Linux kernel be used as a starting point To do this copy the configuration file for the system s architecture from the usr src linux 2 4 configs directory to usr src linux 2 4 config If the system has more than one processor copy the file that contains the keyword smp However if the system has more than four gigabytes of memory copy the file that contains the keyword hugemem 4 Next customize the settings The recommended method is to use the command make menuconfig to run the Linux Kernel Configuration program The X Window System is not required After finishing the configuration select Exit and select Yes to save the new kernel configuration file usr src linux
80. list A IPP browsed queue printer can not be set as the default printer in the Printer Configuration Tool To make an IPP printer the default either add it as described in Section 36 2 Adding an IPP Printer and make it the default or use the GNOME Print Manager to set it as the default To start the GNOME Printer Manager select Main Menu gt System Tools gt Print Manager Right click on the queue name and select Set as Default Setting the default printer in the GNOME Print Manager only changes the default printer for the user who configures it it is not a system wide setting After adding the printer s the settings can be edited by selecting the printer from the printer list and clicking the Edit button The tabbed window shown in Figure 36 12 is displayed The window contains the current values for the selected printer Make any necessary changes and click OK Click Apply in the main Printer Configuration Tool window to save the changes and restart the printer daemon Chapter 36 Printer Configuration 259 Queue name Queue type Queue options Printer driver Driver options This is the name of the queue It must begin with a letter and contain no spaces Name printer About This is the description of the printer Short description my printer T Help 3 Cancel 2 OK Figure 36 12 Editing a Printer 36 9 1 Queue Name To rename a printer or change
81. local system Enable LPD protocol This option allows the printer to receive print jobs from clients configured to use the LPD protocol using the cups 1pd service which is an xinetd service 266 Chapter 36 Printer Configuration A warming If this option is enabled all print jobs are accepted from all hosts if they are received from an LPD client Queue General These settings are system wide lt Automatically find remote shared queues Enable LPD protocol K Help Cancel 2 OK Figure 36 19 System wide Sharing Options 36 14 Additional Resources To learn more about printing on Red Hat Enterprise Linux refer to the following resources 36 14 1 Installed Documentation map lpr The manual page for the 1pr command that allows you to print files from the command line man 1lprm The manual page for the command line utility to remove print jobs from the print queue man mpage The manual page for the command line utility to print multiple pages on one sheet of paper man cupsd The manual page for the CUPS printer daemon man cupsd conf The manual page for the CUPS printer daemon configuration file man classes conf The manual page for the class configuration file for CUPS 36 14 2 Useful Websites http www linuxprinting org GNU Linux Printing contains a large amount of information abo
82. may not properly recognize the changes Data could be overwitten by writing to the wrong partition because the partition table and partitions mounted do not match The easiest way to achieve this is to boot your system in rescue mode Refer to Chapter 11 Basic System Recovery for instructions on booting into rescue mode When prompted to mount the file system select Skip Alternately if the drive does not contain any partitions in use you can unmount them and turn off all the swap space on the hard drive with the swapof f command 2 Create the swap partition using parted At a shell prompt as root type the command parted dev hdb where dev hdb is the device name for the hard drive with free space Atthe parted prompt type print to view the existing partitions and the amount of free space The start and end values are in megabytes Determine how much free space is on the hard drive and how much you want to allocate for a new swap partition At the parted prompt type mkpartfs part type linux swap start end where part type is one of primary extended or logical start is the starting point of the partition and end is the end point of the partition 6 Chapter 2 Swap Space A waming Changes take place immediately be careful when you type Exit parted by typing quit 3 Now that you have created the swap partition use the command mkswap to setup the swap partition At a shell prompt as root type the following mksw
83. modules onto your secure server using Apache s DSO functionality If you do not intend to load other modules onto your Apache HTTP Server you do not need to install this package OpenSSH packages The OpenSSH packages provide the OpenSSH set of network connectivity tools for logging into and executing commands on a remote machine OpenSSH tools encrypt all traffic includ ing passwords so you can avoid eavesdropping connection hijacking and other attacks on the communications between your machine and the remote machine The openssh package includes core files needed by both the OpenSSH client programs and the OpenSSH server The openssh package also contains scp a secure replacement for rcp for copying files between machines The openssh askpass package supports the display of a dialog window which prompts for a password during use of the OpenSSH agent The openssh askpass gnome package can be used in conjunction with the GNOME desktop environment to display a graphical dialog window when OpenSSH programs prompt for a pass word If you are running GNOME and using OpenSSH utilities you should install this package The openssh server package contains the sshd secure shell daemon and related files The secure shell daemon is the server side of the OpenSSH suite and must be installed on your host to allow SSH clients to connect to your host The openssh clients package contains the client programs needed to make encrypted con
84. must begin with a letter The printer name may contain letters numbers dashes and underscores _ Optionally enter a short description for the printer which can contain spaces After clicking Forward Figure 36 5 appears Select Networked CUPS IPP from the Select a queue type menu Select a queue type Networked CUPS IPP z Server Path servername example com printers queuel is Help Cancel gq Back p gt Eorward Figure 36 5 Adding an IPP Printer Text fields for the following options appear Server The hostname or IP address of the remote machine to which the printer is attached Path The path to the print queue on the remote machine Click Forward to continue Next select the printer type Refer to Section 36 7 Selecting the Printer Model and Finishing for details important The networked IPP print server must allow connections from the local system Refer to Section 36 13 Sharing a Printer for more information 36 3 Adding a Remote UNIX LPD Printer To add a remote UNIX printer such as one attached to a different Linux system on the same network click the New button in the main Printer Configuration Tool window The window shown in Figure 36 2 will appear Click Forward to proceed In the window shown in Figure 36 3 enter a unique name for the printer in the Name text field The printer name cannot contain spaces and must begin wi
85. name of the package is displayed bar 2 0 20 3 1386 rpm To force the installation anyway a bad idea since the package probably will not run correctly use the nodeps option 16 2 3 Uninstalling Uninstalling a package is just as simple as installing one Type the following command at a shell prompt rpm e foo Note Notice that we used the package name foo not the name of the original package file foo 1 0 1 1386 rpm To uninstall a package replace foo with the actual package name of the original package You can encounter a dependency error when uninstalling a package if another installed package de pends on the one you are trying to remove For example Chapter 16 Package Management with RPM 107 Preparing HAART AE AE AE AE AE RARE ATH RAAT AEE E EE 1005 error removing these packages would break dependencies foo is needed by bar 2 0 20 3 i386 rpm To cause RPM to ignore this error and uninstall the package anyway which is also a bad idea since the package that depends on it will probably fail to work properly use the nodeps option 16 2 4 Upgrading Upgrading a package is similar to installing one Type the following command at a shell prompt rpm Uvh foo 2 0 1 i386 rpm What you do not see above is that RPM automatically uninstalled any old versions of the foo package In fact you may want to always use U to install packages since it works even when there are no previous versions of the package inst
86. of software packages are installed Because people use their com puters differently users might want to install or remove packages after installation The Package Management Tool allows users to perform these actions The X Window System is required to run the Package Management Tool To start the application go to the Main Menu Button on the Panel gt System Settings gt Add Remove Applications or type the command redhat config packages at shell prompt The same interface appears if you insert the Red Hat Enterprise Linux CD 1 into your computer Add or Remove Packages Ce X Window System 35 36 Details K Install this group of packages to use the base graphical X amp user interface GNOME Desktop Environment 34 34 Details wee GNOME is a powerful graphical user interface which X includes a panel desktop system icons and a graphical file manager KDE Desktop Environment 0 15 y gt KDE is a powerful graphical user interface which includes ws a panel desktop system icons and a graphical file manager Applications Editors 0 3 a Sometimes called text editors these are programs that v Total install size 1 369 Megabytes Dau Update Figure 17 1 Package Management Tool The interface for this application is similar to the one used for individual package selection during installation Packages are divided into package groups
87. options for the system It s similar to the authconfig command which can be run after the install By default passwords are normally encrypted and are not shadowed enablemd5 Use md5 encryption for user passwords Chapter 9 Kickstart Installations 41 enablenis Turns on NIS support By default enablenis uses whatever domain it finds on the network A domain should almost always be set by hand with the nisdomain option nisdomain NIS domain name to use for NIS services nisserver Server to use for NIS services broadcasts by default useshadow or enableshadow Use shadow passwords enableldap Turns on LDAP support in etc nsswitch conf allowing your system to retrieve infor mation about users UIDs home directories shells etc from an LDAP directory To use this option you must install the nss_ldap package You must also specify a server and a base DN with 1dapserver and ldapbasedn enableldapauth Use LDAP as an authentication method This enables the pam_ldap module for authen tication and changing passwords using an LDAP directory To use this option you must have the nss_ldap package installed You must also specify a server and a base DN with ldapserver and ldapbasedn ldapserver If you specified either enableldap or enableldapauth use this option to specify the name of the LDAP server to use This option is set in the etc ldap conf file ldapba
88. sends back a certificate for your secure server A secure server uses a certificate to identify itself to Web browsers You can generate your own certificate called a self signed certificate or you can get a certificate from a CA A certificate from a reputable CA guarantees that a website is associated with a particular company or organization Alternatively you can create your own self signed certificate Note however that self signed certifi cates should not be used in most production environments Self signed certificates are not automat ically accepted by a user s browser users are prompted by the browser to accept the certificate and create the secure connection See Section 27 5 Types of Certificates for more information on the differences between self signed and CA signed certificates Once you have a self signed certificate or a signed certificate from the CA of your choice you need to install it on your secure server 27 4 Using Pre Existing Keys and Certificates If you already have an existing key and certificate for example if you are installing the secure server to replace another company s secure server product you can probably be able to use your existing 206 Chapter 27 Apache HTTP Secure Server Configuration key and certificate with the secure server In the following two situations you are not able to use your existing key and certificate If you are changing your IP address or domain name Cer
89. server gt as file lt path gt The installation program will use DHCP to configure the Ethernet card For example if your HTTP server is server example com and the kickstart file is in the HTTP directory mydir ks cfg the correct boot command would be ks http server example com mydir ks cfg floppy The installation program looks for the file ks cfg on a vfat or ext2 file system on the diskette in dev fdqd0 floppy lt path gt The installation program will look for the kickstart file on the diskette in dev fd0 as file lt path gt hd lt device gt lt file gt The installation program will mount the file system on lt device gt which must be vfat or ext2 and look for the kickstart configuration file as lt file gt in that file system for example ks hd sda3 mydir ks cfg file lt file gt The installation program will try to read the file lt file gt from the file system no mounts will be done This is normally used if the kickstart file is already on the initrd image cdrom lt path gt The installation program will look for the kickstart file on CD ROM as file lt path gt If ks is used alone the installation program will configure the Ethernet card to use DHCP The kickstart file is read from the bootServer from the DHCP response as if it is an NFS server sharing the kickstart file By default the bootServer is the same as the DHCP server The name of the kickstart file is one of the following
90. swap space Chapter 2 Swap Space redhat Chapter 3 Redundant Array of Independent Disks RAID 3 1 What is RAID The basic idea behind RAID is to combine multiple small inexpensive disk drives into an array to accomplish performance or redundancy goals not attainable with one large and expensive drive This array of drives appears to the computer as a single logical storage unit or drive RAID is a method in which information is spread across several disks using techniques such as disk striping RAID Level 0 disk mirroring RAID level 1 and disk striping with parity RAID Level 5 to achieve redundancy lower latency and or increase bandwidth for reading or writing to disks and maximize the ability to recover from hard disk crashes The underlying concept of RAID is that data may be distributed across each drive in the array in a consistent manner To do this the data must first be broken into consistently sized chunks often 32K or 64K in size although different sizes can be used Each chunk is then written to a hard drive in RAID according to the RAID level used When the data is to be read the process is reversed giving the illusion that multiple drives are actually one large drive 3 2 Who Should Use RAID Anyone who needs to keep large quantities of data on hand such as a system administrator would benefit by using RAID technology Primary reasons to use RAID include Enhanced speed Increased storage capac
91. the hardware list on the Hardware tab Configure DSL connection a Select the ethemet device for this account Ethernet Device ethO 82557 8 9 Ethernet Pro 100 w Enter the provider name for this account Provider Name T Online Account Setup Enter the login name for this account Login Name Enter the password for this account Password 3 Cancel lt Back D Forward Figure 19 8 xDSL Settings 5 If the Select Ethernet Adapter window appears select the manufacturer and model of the Ethernet card Select the device name If this is the system s first Ethernet card select eth0 as the device name if this is the second Ethernet card select eth1 and so on The Network Administration Tool also allows you to configure the resources for the NIC Click Forward to continue 6 Enter the Provider Name Login Name and Password If you have a T Online account instead of entering a Login Name and Password in the default window click the T Online Account Setup button and enter the required information Click Forward to continue 7 On the Create DSL Connection page click Apply After configuring the DSL connection it appears in the device list as shown in Figure 19 7 130 Chapter 19 Network Configuration File Profile Help arf Bg xX New Edit Copy Delete Activate Deactivate Devices Hardware IPsec DNS Hosts
92. the Panel gt System Tools gt System Logs or type the command redhat logviewer at a shell prompt The application only displays log files that exist thus the list might differ from the one shown in Figure 38 1 To filter the contents of the log file for keywords type the keyword or keywords in the Filter for text field and click Filter Click Reset to reset the contents File Edit Help Boot Log System Log Cron Log Kemel Startup Log GDS This is the system log file Mail Log MySQL Server Log May 14 16 50 51 falcon su pam_unix 13618 session opened for user root by tfox uil May 14 17 42 18 falcon su pam_unix 13618 session closed for user root News Log May 14 03 falcon su pam_unix 14359 session opened for user root by tfox uii RPM Packages May 15 04 12 35 falcon su pam_unix 16201 session opened for user news by uid Security Log May 15 04 12 35 falcon su pam_unix 16201 session closed for user news System Log Update Agent Log XFree86 Log _ May 15 08 39 28 falcon sshd pam_unix 10501 session closed for user tfox may 15 14 12 53 falcon xscreensaver pam_unix 2616 authentication failure lognam _ May 15 14 12 54 falcon xscreensaver 2616 pam_krb5 authentication succeeds for may 15 14 38 16 falcon sshd pam_unix 17631 authentication failure logname uid May 15 14 38 16 falcon sshd 17631 pam_krb5 authentication succeeds for tfox May 15 14 38 16 falc
93. the company hosting it 3 Send the certificate request along with documents proving your identity to a CA We cannot tell you which certificate authority to choose Your decision may be based on your past experiences or on the experiences of your friends or colleagues or purely on monetary factors Once you have decided upon a CA you need to follow the instructions they provide on how to obtain a certificate from them 4 When the CA is satisfied that you are indeed who you claim to be they send you a digital certificate 5 Install this certificate on your secure server and begin handling secure transactions Whether you are getting a certificate from a CA or generating your own self signed certificate the first step is to generate a key See Section 27 6 Generating a Key for instructions on how to generate a key 27 6 Generating a Key You must be root to generate a key First cd to the etc httpd conf directory Remove the fake key and certificate that were gener ated during the installation with the following commands rm ssl key server key rm ssl crt server crt Next you need to create your own random key Change to the usr share ssl certs directory and type in the following command make genkey Your system displays a message similar to the following 208 Chapter 27 Apache HTTP Secure Server Configuration umask 77 usr bin openssl genrsa des3 1024 gt etc httpd conf ssl key server key Generating R
94. the first CD ROM drive on the system harddrive Install from a Red Hat installation tree on a local drive which must be either vfat or ext2 e partition Partition to install from such as sdb2 e dir Directory containing the RedHat directory of the installation tree For example harddrive partition hdb2 dir tmp install tree nfs Install from the NFS server specified Server Server from which to install hostname or IP Chapter 9 Kickstart Installations 47 e dir Directory containing the RedHat directory of the installation tree For example nfs server nfsserver example com dir tmp install tree url Install from an installation tree on a remote server via FTP or HTTP For example url url http lt server gt lt dir gt or url url ftp lt username gt lt password gt lt server gt lt dir gt interactive optional Uses the information provided in the kickstart file during the installation but allow for inspection and modification of the values given You will be presented with each screen of the installation program with the values from the kickstart file Either accept the values by clicking Next or change the values and click Next to continue See also autostep keyboard required Sets system keyboard type Here is the list of available keyboards on i386 Itanium and Alpha machines be latinl bg br abnt2 cf cz lat2 cz us qwertz de de latinl de latinl nodeadkeys
95. the program is an end user application as opposed to system software For example Use Mozilla to browse the Web key A key on the keyboard is shown in this style For example To use Tab completion type in a character and then press the Tab key Your terminal displays the list of files in the directory that start with that letter key combination A combination of keystrokes is represented in this way For example The Ctrl Alt Backspace key combination exits your graphical session and return you to the graphical login screen or the console text found on a GUI interface A title word or phrase found on a GUI interface screen or window is shown in this style Text shown in this style is being used to identify a particular GUI screen or an element on a GUI screen such as text associated with a checkbox or field Example Select the Require Password checkbox if you would like your screensaver to require a password before stopping top level of a menu on a GUI screen or window A word in this style indicates that the word is the top level of a pulldown menu If you click on the word on the GUI screen the rest of the menu should appear For example Under File on a GNOME terminal the New Tab option allows you to open multiple shell prompts in the same window If you need to type in a sequence of commands from a GUI menu they are shown like the following example Go to Main Menu Button on the Panel gt Programm
96. the systems in a network To share files between Linux machines only use NFS as discussed in Chapter 23 Network File System NFS To share printers between Linux machines only you do not need to use Samba refer to Chapter 36 Printer Configuration 24 2 Configuring a Samba Server The default configuration file etc samba smb conf allows users to view their home directories as a Samba share It also shares all printers configured for the system as Samba shared printers In other words you can attach a printer to the system and print to it from the Windows machines on your network 24 2 1 Graphical Configuration To configure Samba using a graphical interface use the Samba Server Configuration Tool For command line configuration skip to Section 24 2 2 Command Line Configuration The Samba Server Configuration Tool is a graphical interface for managing Samba shares users and basic server settings It modifies the configuration files in the etc samba directory Any changes to these files not made using the application are preserved To use this application you must be running the X Window System have root privileges and have the redhat config samba RPM package installed To start the Samba Server Configuration Tool from the desktop go to the Main Menu Button on the Panel gt System Settings gt Server Set tings gt Samba or type the command redhat config samba at a shell prompt for example in an XTerm or a GNOME terminal
97. to enable networking and the configuration file for each network device in the etc sysconfig network scripts directory In this directory each device should have a configuration file named ifcfg eth0 where etho is the network device name The etc sysconfig network file should contain the following line NETWORKING yes The NETWORKING variable must be set to yes if you want networking to start at boot time The etc sysconfig network scripts ifcfg eth0 file should contain the following lines DEVICE eth0 BOOTPROTO dhcp ONBOOT yes A configuration file is needed for each device to be configured to use DHCP Other options for the network script include DHCP_HOSTNAME Only use this option if the DHCP server requires the client to specify a host name before receiving an IP address The DHCP server daemon in Red Hat Enterprise Linux does not support this feature PEERDNS lt answer gt where lt answer gt is one of the following yes Modify etc resolv conf with information from the server If using DHCP then yes is the default no Do not modify etc resolv conf SRCADDR lt address gt where lt address gt is the specified source IP address for outgoing pack ets USERCTL lt answer gt where lt answer gt is one of the following yes Non root users are allowed to control this device no Non root users are not allowed to control this device For a graphical interface for configuring a
98. to upgrade these packages the versions might vary rpm Uvh kernel source 2 4 21 1 1931 2 399 ent lt arch gt rpm rpm Uvh kernel utils 2 4 21 1 1931 2 399 ent lt arch gt rpm The next step is to verify that the initial RAM disk image has been created Refer to Section 39 5 Verifying the Initial RAM Disk Image for details 39 5 Verifying the Initial RAM Disk Image If the system uses the ext3 file system a SCSI controller or uses labels to reference partitions in etc fstab an initial RAM disk is needed The initial RAM disk allows a modular kernel to have access to modules that it might need to boot from before the kernel has access to the device where the modules normally reside On the Red Hat Enterprise Linux architectures other than IBM eServer iSeries the initial RAM disk can be created with the mkinitrd command However this step is performed automatically if the kernel and its associated packages are installed or upgraded from the RPM packages distributed by Red Hat Inc thus it does not need to be executed manually To verify that it was created use the command 1s 1 boot to make sure the initrd lt version gt img file was created the version should match the version of the kernel just installed On iSeries systems the initial RAM disk file and vmlinux file are combined into one file which is created with the addRamDisk command This step is performed automatically if the kernel and its associated packages are instal
99. uncheck the corresponding checkbox Click Forward 7 If your ISP is in the pre configured list select it Otherwise enter the required information about your ISP account If you do not know these values contact your ISP Click Forward 8 On the IP Settings page select whether to obtain an IP address automatically or whether to set on statically Click Forward when finished 9 On the Create Dialup Connection page click Apply After configuring the modem device it appears in the device list with the type Modem as shown in Figure 19 7 File Profile Help SfHB F x New Edit Copy Delete Activate Deactivate Devices Hardware IPsec DNS Hosts guc You may configure network devices associated with 3 o physical hardware here Multiple logical devices can be T associated with a single piece of hardware Profile Status Device Nickname Type Ve eae Modem Figure 19 7 Modem Device Be sure to select File gt Save to save the changes After adding the modem device you can edit its configuration by selecting the device from the device list and clicking Edit For example when the device is added it is configured not to start at boot time by default Edit its configuration to modify this setting Compression PPP options login name password and more can also be changed When the device is added it is not activated immediately as seen by its Inactive status
100. use the following command cp usr share doc dhcp lt version number gt dhcpd conf sample etc dhcpd conf where lt version number gt is the DHCP version number For a complete list of option statements and what they do refer to the dhcp opt ions man page 25 2 2 Lease Database On the DHCP server the file var lib dhcp dhcpd leases stores the DHCP client lease database This file should not be modified by hand DHCP lease information for each recently assigned IP address is automatically stored in the lease database The information includes the length of the lease to whom the IP address has been assigned the start and end dates for the lease and the MAC address of the network interface card that was used to retrieve the lease All times in the lease database are in Greenwich Mean Time GMT not local time The lease database is recreated from time to time so that it is not too large First all known leases are saved in a temporary lease database The dhcpd leases file is renamed dhcpd leases and the temporary lease database is written to dhcpd leases The DHCP daemon could be killed or the system could crash after the lease database has been renamed to the backup file but before the new file has been written If this happens the dhcpd leases file does not exist but it is required to start the service Do not create a new lease file If you do all the old leases will be lost and cause many problems The correct solution is t
101. user s properties after adding the user Refer to Section 35 2 Modifying User Properties for more information To add the user to more user groups click on the User tab select the user and click Properties In the User Properties window select the Groups tab Select the groups that you want the user to be a member of select the primary group for the user and click OK 35 2 Modifying User Properties To view the properties of an existing user click on the Users tab select the user from the user list and click Properties from the button menu or choose File gt Properties from the pulldown menu A window similar to Figure 35 3 appears Chapter 35 User and Group Configuration 241 User Data Account Info Password Info Groups User Name tfox Full Name Tammy Fox Password Confirm Password Home Directory home tfox Login Shell bin bash 3 Cancel 2 OK Figure 35 3 User Properties The User Properties window is divided into multiple tabbed pages User Data Shows the basic user information configured when you added the user Use this tab to change the user s full name password home directory or login shell Account Info Select Enable account expiration if you want the account to expire on a certain date Enter the date in the provided fields Select User account is locked to lock the user account so that the user cannot log in to t
102. v bash tfox 1 4MB 0 27863 gnome system monitor tfox 89MB 1 28130 metacity tfox 66MB 0 27041 mixer_applet2 tfo 83MB 0 27075 F mozilla bin tfox 20 6 MB 0 27650 gt nautilus tfox 16 8 MB 0 27053 More Info gt gt Figure 42 1 GNOME System Monitor 42 2 Memory Usage 295 The free command displays the total amount of physical memory and swap space for the system as well as the amount of memory that is used free shared in kernel buffers and cached total Mem 256812 buffers cache Swap 265032 used 240668 108300 780 free 16144 148512 264252 buffers 50520 cached 81848 shared 105176 The command free m shows the same information in megabytes which are easier to read total Mem 250 buffers cache Swap 258 used 235 105 0 free 15 145 258 buffers 49 cached 79 shared 102 If prefer a graphical interface for free you can use the GNOME System Monitor To start it from the desktop go to the Main Menu Button on the Panel gt System Tools gt System Monitor or type gnome system monitor at a shell prompt from within X Window System Then choose the System Monitor tab 296 Chapter 42 Gathering System Information File Edit View Help Process Listing ystem Monitor CPU Usage History EE CPU Used 3 50 Memory Swap Usage History E Memory Used 710MB Total 1006 MB Swap Used 0 bytes Total 1 9 GB Devices Name
103. want to save your generated key pair backup the ssh directory in your home directory After reinstalling copy this directory back to your home directory This process can be done for all users on your system including root 22 3 4 1 Generating an RSA Key Pair for Version 2 Use the following steps to generate an RSA key pair for version 2 of the SSH protocol This is the default starting with OpenSSH 2 9 160 a Chapter 22 OpenSSH To generate an RSA key pair to work with version 2 of the protocol type the following command at a shell prompt ssh keygen t rsa Accept the default file location of ssh id_rsa Enter a passphrase different from your account password and confirm it by entering it again The public key is written to ssh id_rsa pub The private key is written to ssh id_rsa Never distribute your private key to anyone Change the permissions of the ssh directory using the following command chmod 755 ssh Copy the contents of ssh id_rsa pub to ssh authorized_keys on the machine to which you want to connect If the file ssh authorized_keys exist append the contents of the file ssh id_rsa pub to the file ssh authorized_keys on the other machine Change the permissions of the authorized_keys file using the following command chmod 644 ssh authorized_keys If you are running GNOME skip to Section 22 3 4 4 Configuring ssh agent with GNOME If you are not running the X
104. which contain a list of standard packages and extra packages that share common functionality For example the Graphical Internet group contains a Web browser email client and other graphical programs used to connected to the Internet The standard packages can not be selected for removal unless the entire package group is removed The extra packages are optional packages that can be selected for installation or removal as long as the package group is selected The main window shows a list of package groups If the package group has a checkmark in the checkbox beside it packages from that group are currently installed To view the individual packages list for a group click the Details button beside it The individual packages with a checkmark beside them are currently installed 114 Chapter 17 Package Management Tool 17 1 Installing Packages To install the standard packages in a package group that is not currently installed check the checkbox beside it To customize the packages to be installed within the group click the Details button beside it The list of standard and extra packages is displayed as shown in Figure 17 2 Clicking on the package name displays the disk space required to install the package at the bottom of the window Checking the checkbox beside the package name marks it for installation You can also select individual packages from already installed package groups by click the Details button and checking any of the ext
105. which requests a document from your Web server Resolving the IP address means that your server will make one or more connections to the DNS in order to find out the hostname that corre sponds to a particular IP address If you choose Double Reverse Lookup your server will perform a double reverse DNS In other words after a reverse lookup is performed a forward lookup is performed on the result At least one of the IP addresses in the forward lookup must match the address from the first reverse lookup Generally you should leave this option set to No Reverse Lookup because the DNS requests add a load to your server and may slow it down If your server is busy the effects of trying to perform these reverse lookups or double reverse lookups may be quite noticeable Reverse lookups and double reverse lookups are also an issue for the Internet as a whole All of the individual connections made to look up each hostname add up Therefore for your own Web server s benefit as well as for the Internet s benefit you should leave this option set to No Reverse Lookup 194 Chapter 26 Apache HTTP Server Configuration 26 2 3 Environment Variables Sometimes it is necessary to modify environment variables for CGI scripts or server side include SSI pages The Apache HTTP Server can use the mod_env module to configure the environment variables which are passed to CGI scripts and SSI pages Use the Environment Variables page to configure the direc
106. 2 hid usb uhci ext3 91464 2 jbd 56336 2 ext3 For each line the first column is the name of the module the second column is the size of the module and the third column is the use count The information after the use count varies slightly per module If unused is listed on the line for the module the module is currently not being used If autoclean is on the line for the module the module can be autocleaned by the rmmod a command When this command is executed any modules that are tagged with autoclean that have not been used since the previous autoclean action are unloaded Red Hat Enterprise Linux does not perform this autoclean action by default If a module name is listed at the end of the line in brackets the module in the brackets is dependent on the module listed in the first column of the line For example in the line usbcore 82752 1 hid usb uhci the hid and usb uhci kernel modules depend on the usbcore module The sbin 1smod output is the same as the output from viewing proc modules To load a kernel module use the sbin modprobe command followed by the kernel module name By default modprobe attempts to load the module from the lib modules lt kernel version gt kernel drivers subdirectories There is a subdirectory for each type of module such as the net subdirectory for network interface drivers Some kernel modules have module dependencies meaning that other modules must be loaded first for it to load
107. 2 4 config Even if no changes were made to any of the settings running the make menuconfig command or one of the other methods for kernel configuration is required before continuing Other available methods for kernel configuration include make config An interactive text program Components are presented in a linear format and answered one at a time This method does not require the X Window System and does not allow answers to be changed for previous questions make xconfig The method requires the X Window System and the tk package This method is not recommended because it does not parse the configuration files reliably e make oldconfig This is a non interactive script that reads the existing configuration file config and only prompts for answers to any new questions that did not previously exist G Note To use kmod and kernel modules answer Yes to kmod support and module version CONFIG_MODVERSIONS support during the configuration 5 After creating a usr src linux 2 4 config file use the command make dep to set up the dependencies correctly 6 Use the command make clean to prepare the source tree for the build 7 It is recommended that the custom kernel have a modified version number so that the existing kernel is not overwritten The method described here is the easiest to recover from in the event of a mishap For other possibilities details can be found at http www redhat com mirrors LDP H
108. 3 Model Maxtor 52049H3 i New Edit Reset RAD Deae aes Tee roma ae sin ena LM Voume Groupe Votumeoo 3005 Logvow0 home ex3 v 30000 had ies S favan i idevihdat boot ex3 s 78 1 10 idevihda2 Volume00 LVMPV 4 19391 11 2482 S evn idev hdb1 swap 4 1992 1 254 dev VouimeooLvMPY A 17477 288 zane Ll te RAID aove VM Vole Group meer Back gt Next Figure 13 4 Logical Volumes Created 90 Chapter 13 LVM Configuration redhat Chapter 14 PXE Network Installations Red Hat Enterprise Linux allows for installation over a network using the NFS FTP or HTTP proto cols A network installation can be started from a network boot diskette a boot CD ROM or by using the askmethod boot option with the Red Hat Enterprise Linux CD 1 Alternatively if the system to be installed contains a network interface card NIC with Pre Execution Environment PXE sup port it can be configured to boot from files on another system on the network instead of a diskette or CD ROM For a PXE network installation the client s NIC with PXE support sends out a broadcast request for DHCP information The DHCP server provides the client with an IP address other network infor mation such as name server the IP address or hostname of the t ftp server which provides the files necessary to start the installation program and the location of the files on the tftp server This is possible bec
109. 3 Fil Sy Sten ahars aa AO raa OO E aAa anaa 1 1 l Feattires OF EXB nenn ae S a VEEE E E A E EER 1 1 2 Creating an ext3 File System 1 3 Converting to an ext3 File System 1 4 Reverting to an ext2 File System 2 Swap Space aisaen iee 2 1 What is Swap Space 2 2 Adding Swap Space 2 3 Removing Swap Space 2 4 Moving Swap Space 3 Redundant Array of Independent Disks RAID 0 ceeececseee ee eecseseseeeeecseseeesenetseseseeee 9 3 17 What is RAID eie rrin yE SEE EEEE secretin neice ness 9 3 4 RAID Levels and Linear Support eee eseseeseeesescaceececeeseseseeesesseseeeeenees 10 4 Logical Volume Manager LVM PAE 4 1 What is LVM 13 4 2 Additional Resources 14 5 Managing Disk Storage 0 15 5 1 Viewing the Partition Table 16 5 2 Creating a Partition sion e oeei EEEE SET E tees ES EEE R E 5 3 Removing a Partition 5 4 Resizing a Partition sii 6 Implemnentne Disk Quotas se ies eris peer sarsies VERa AVE AEETI ESEE EREA EAIN 21 6 1 Configuring Disk Quotas soseen nsien a iri ii 21 6 2 Managing Disk Quotas 6 3 Additional REsOUrces serisini torrie E r E i E i 7 User Defined Device Naeser arisisitiiirissiy tioii eaea EE EENE EE EEEE ER 7 1 Configuring Devlabel 7 2 How It Works 7 3 Additional Resources 8 Access Control Lists 0 0 0 8 1 Mounting File Systems 2 8 2 Settin T Access ACLS iieiaeie snae E
110. 4 ntsysv The ntsysv utility provides a simple interface for activating or deactivating services You can use ntsysv to turn an xinetd managed service on or off You can also use ntsysv to configure runlevels By default only the current runlevel is configured To configure a different runlevel specify one or more runlevels with the level option For example the command ntsysv level 345 con figures runlevels 3 4 and 5 The ntsysv interface works like the text mode installation program Use the up and down arrows to navigate up and down the list The space bar selects unselects services and is also used to press the OK and Cancel buttons To move between the list of services and the Ok and Cancel buttons use the Tab key An signifies that a service is set to on Pressing the F1 key displays a short description of the selected service waming Services managed by xinetd are immediately affected by ntsysv For all other services changes do not take effect immediately You must stop or start the individual service with the command service Chapter 21 Controlling Access to Services 155 daemon stop In the previous example replace daemon with the name of the service you want to stop for example httpd Replace stop with start or restart to start or restart the service 21 5 chkconfig The chkconfig command can also be used to activate and deactivate services The chkconfig list command displays a list of system services a
111. 5sum by typing the following command at a shell prompt lt rpm file gt with filename of the RPM package rpm K nogpg lt rpm file gt The message lt rpm file gt md5 OK is displayed This brief message means that the file was not corrupted by the download To see a more verbose message replace K with Kvv in the command On the other hand how trustworthy is the developer who created the package If the package is signed with the developer s GnuPG key you know that the developer really is who they say they are An RPM package can be signed using Gnu Privacy Guard or GnuPG to help you make certain your downloaded package is trustworthy GnuPG is a tool for secure communication it is a complete and free replacement for the encryption technology of PGP an electronic privacy program With GnuPG you can authenticate the validity of documents and encrypt decrypt data to and from other recipients GnuPG is capable of decrypting and verifying PGP 5 x files as well 110 Chapter 16 Package Management with RPM During installation GnuPG is installed by default That way you can immediately start using GnuPG to verify any packages that you receive from Red Hat First you need to import Red Hat s public key 16 3 1 Importing Keys To verify Red Hat packages you must import the Red Hat GPG key To do so execute the following command at a shell prompt rpm import usr share rhn RPM GPG KEY To display a list of all keys
112. 6 system using LILO as the boot loader at the LILO boot prompt if you are using the graphical LILO you must press Ctrl x to exit the graphical screen and go to the boot prompt type linux single For all other platforms specify single as a kernel parameter at the boot prompt 11 4 Booting into Emergency Mode In emergency mode you are booted into the most minimal environment possible The root file system is be mounted read only and almost nothing is set up The main advantage of emergency mode over single user mode is that the init files are not loaded If init is corrupted or not working you can still mount file systems to recover data that could be lost during a re installation To boot into emergency mode use the same method as described for single user mode in Section 11 3 Booting into Single User Mode with one exception replace the keyword single with the keyword emergency redhat Chapter 12 Software RAID Configuration Read Chapter 3 Redundant Array of Independent Disks RAID first to learn about RAID the differ ences between Hardware and Software RAID and the differences between RAID 0 1 and 5 Software RAID can be configured during the graphical installation of Red Hat Enterprise Linux or during a kickstart installation This chapter discusses how to configure software RAID during instal lation using the Disk Druid interface Before you can create a RAID device you must first create RAID partitions usi
113. 8 1 General The first step in configuring X is to choose the default color depth and resolution Select them from their respective pulldown menus Be sure to specify a color depth and resolution that is compatible with the video card and monitor for the system Chapter 10 Kickstart Configurator 73 File Help Basic Configuration X Configuration Installation Method 4 Configure the X Window System Boot Loader Options General Video Card Monitor Partition Information Color Depth ka Resolution Network Configuration 8 640x480 y Authentication z 3 Firewall Configuration Default Desktop GNOME O KDE X Configuration C Start the X Window System on boot Package Selection On first boot Setup Agent is Disabled T Pre Installation Script Post nstallation Script Figure 10 11 X Configuration General If you are installing both the GNOME and KDE desktops you must choose which desktop should be the default If only one desktop is to be installed be sure to choose it Once the system is installed users can choose which desktop they want to be their default Next choose whether to start the X Window System when the system is booted This option will start the system in runlevel 5 with the graphical login screen After the system is installed this can be changed by modifying the etc inittab configuration file Also select whether to start the Setup Agent t
114. Aubry French translations David Barzilay Brazilian Portuguese translations Bernd Groh German translations James Hashida Japanese translations Michelle Ji yeen Kim Korean translations Yelitza Louze Spanish translations Noriko Mizumoto Japanese translations Nadine Richter German translations Audrey Simons French translations Francesco Valente Italian translations Sarah Saiying Wang Simplified Chinese translations Ben Hung Pin Wu Traditional Chinese translations 330
115. Contributing Writer to the Red Hat Enterprise Linux Installation Guide for the x86 Itanium and AMD64 Architectures Contributing Writer to the Red Hat Enterprise Linux Security Guide Con tributing Writer to the Red Hat Enterprise Linux Step By Step Guide Writer Maintainer of custom DocBook stylesheets and scripts Edward C Bailey Primary Writer Maintainer of the Red Hat Enterprise Linux Introduction to System Administration Primary Writer Maintainer of the Release Notes Contributing Writer to the Red Hat Enterprise Linux Installation Guide for the x86 Itanium and AMD64 Architectures Johnray Fuller Primary Writer Maintainer of the Red Hat Enterprise Linux Reference Guide Co writer Co maintainer of the Red Hat Enterprise Linux Security Guide Contributing Writer to the Red Hat Enterprise Linux Introduction to System Administration John Ha Primary Writer Maintainer of the Red Hat Cluster Suite Configuring and Managing a Cluster Primary Writer Maintainer of the Red Hat Glossary Primary Writer Maintainer of the Red Hat Enterprise Linux Installation Guide for the IBM S 390 and IBM eServer zSeries Ar chitectures Co writer Co maintainer of the Red Hat Enterprise Linux Security Guide Contributing Writer to the Red Hat Enterprise Linux Introduction to System Administration Contributing Writer to the Red Hat Enterprise Linux Step By Step Guide The Red Hat Localization Team consists of the following people Jean Paul
116. EEE EEE EE SEEKOR 31 8 3 Setting Default ACES aissent ai E ES a E E OS A O 32 8 4 Retrieving ACLs K 8 5 Archiving File Systems With ACLs ss ssssessssesssesrssessssrertsssrrsrisrsessnrrnreresesne 33 8 6 Compatibility with Older Systems ss sssssssssessssierestssssrestersrrrrsrssesenrssreresess 34 8 7 Additonal Resources wys sccsssccasesssdeccsasssascateasstetdsasscasssestadavesecuaisnsabs sasssavbascsitianseve 34 IL Installation Related Information scssccsssssssscsssscsssssescecsscssssscsscssscsssssssecsesssessecsecseccssscses 37 9 Kickstart Installations s25s0523siassseavesssavovsaesbss2iids data AES ATR E EaI EAEE a 39 9 1 What are Kickstart Installations 9 2 How Do You Perform a Kickstart Installation 9 3 Creating the Kickstart File 9 4 Kickstart Options 9 5 Package Selection Be 9 6 Pr installation Scripts vaceccsists a wovencesessteresaetenel ieee eitevdadacun see AEE 9 7 Post installanOn SCripes oes siscs oss vscssdabats gpustesys aes EAA AEAEE EGEE 9 8 Making the Kickstart File Available tee 9 9 Making the Installation Tree Available cece eeesseeececseseeeeeecseseeeeees 59 9 10 Starting a Kickstart Installation eee eeeeeceeeescaeseeecesseseseeeeeeeeseseees 60 10 Kickstart Configurator ie 10 1 Basic Configurations cccecresssie sirati E aE a AR a AEs 10 2 Installation Method segere np EEEE EE EE 10 3 Boot Loader Options 10 4 Partition Infor
117. Encapsulation Mode and whether to obtain an IP address automatically or whether to set one statically Click Forward when finished 7 On the Create Dialup Connection page click Apply After configuring the ISDN device it appears in the device list as a device with type ISDN as shown in Figure 19 5 Be sure to select File gt Save to save the changes After adding the ISDN device you can edit its configuration by selecting the device from the device list and clicking Edit For example when the device is added it is configured not to start at boot time by default Edit its configuration to modify this setting Compression PPP options login name password and more can be changed When the device is added it is not activated immediately as seen by its Inactive status To activate the device select it from the device list and click the Activate button If the system is configured to activate the device when the computer starts the default this step does not have to be performed again Chapter 19 Network Configuration File Profile Help B B F x New Edit Copy Delete Activate Deactivate Devices Hardware IPsec DNS Hosts ji You may configure network devices associated with 3 a physical hardware here Multiple logical devices can be 5 associated with a single piece of hardware Profile Status Device Nickname Type v active pppO Provide D Fi
118. Getting Technical Support Appendix in the Red Hat Enterprise Linux Installation Guide Good luck and thank you for choosing Red Hat Enterprise Linux The Red Hat Documentation Team l File Systems File system refers to the files and directories stored on a computer A file system can have different formats called file system types These formats determine how the information is stored as files and directories Some file system types store redundant copies of the data while some file system types make hard drive access faster This part discusses the ext3 swap RAID and LVM file system types It also discusses the parted utility to manage partitions the devlabe1 utility to create user defined device names and access control lists ACLs to customize file permissions Table of Contents The ext3 File System cscssssssssscesssssssssessssssssssscssesssssessssssssssesssesssessssesesessseessssesessesesssesesesens 1 Swap Space Redundant Array of Independent Disks RAID Logical Volume Manager LVM Managing Disk Storage Implementing Disk Quotas aes User Defined Device Names ssssssssscssssssssssessesseaseacsecsscsesssasessenceasescsocsassonssasencseseacesssossessonce 7PNINAKH WY me ACCESS Control Lists sss eisses aeaee is e vasteoedeshetenssacdessessitsovencteaseedeevensussessadeoceenteastetse redhat Chapter 1 The ext3 File System The default file system is the journaling ext3 file s
119. Home Directory Figure 35 1 User Manager To view a list of local users on the system click the Users tab To view a list of local groups on the system click the Groups tab To find a specific user or group type the first few letters of the name in the Search filter field Press Enter or click the Apply filter button The filtered list is displayed To sort the users or groups click on the column name The users or groups are sorted by the value of that column Red Hat Enterprise Linux reserves user IDs below 500 for system users By default User Manager does not display system users To view all users including the system users uncheck Preferences gt Filter system users and groups from the pulldown menu 35 1 Adding a New User To add a new user click the Add User button A window as shown in Figure 35 2 appears Type the username and full name for the new user in the appropriate fields Type the user s password in the Password and Confirm Password fields The password must be at least six characters Ox The longer the user s password the more difficult it is for someone else to guess it and log in to the user s account without permission It is also recommended that the password not be based on a dictionary term and that the password be a combination of letters numbers and special characters 240 Chapter 35 User and Group Configuration Select a login shell If you are not sure which shell to select
120. M s freshen option does not install a package if no previously installed package of the same name exists This differs from RPM s upgrade option as an upgrade does install packages whether or not an older version of the package was already installed RPMs freshen option works for single packages or a group of packages If you have just downloaded a large number of different packages and you only want to upgrade those packages that are already installed on your system freshening does the job If you use freshening you do not have to delete any unwanted packages from the group that you downloaded before using RPM In this case issue the following command 108 Chapter 16 Package Management with RPM rpm Fvh rpm RPM automatically upgrades only those packages that are already installed 16 2 6 Querying Use the rpm q command to query the database of installed packages The rpm q foo command displays the package name version and release number of the installed package foo foo 2 0 1 i Note Notice that we used the package name foo To query a package you need to replace foo with the actual package name Instead of specifying the package name you can use the following options with q to specify the package s you want to query These are called Package Specification Options e a queries all currently installed packages f lt file gt queries the package which owns lt file gt When specifying a file you mus
121. NS Hosts You may configure IPsec tunnels and host to host connections here Profie Type Destination Nickname 8 100 psecO Figure 19 22 IPsec Connection Two files are created in etc sysconfig network scripts ifcfg lt nickname gt and keys lt nickname gt If automatic encryption is selected etc racoon racoon conf is created as well When the interface is activated lt remote ip gt conf and psk txt are created in etc racoon and racoon conf is modified to include lt remote ip gt conf Refer to Section 19 14 3 Testing the IPsec Connection to determine if the IPsec connection has been successfully established 19 14 2 Network to Network VPN Connection A network to network IPsec connection uses two IPsec routers one for each network through which the network traffic for the private subnets is routed For example as shown in Figure 19 23 if the 192 168 0 24 private network wants to send network traffic to the 192 168 2 0 24 private network the packets go through gateway0 to ipsecO through the Internet to ipsecl to gateway1 and to the 192 168 2 0 24 subnet The IPsec routers must have publically addressable IP addresses as well as another Ethernet device connected to its private network Traffic only travels through it if it is intended for the other IPsec router with which it has an encrypted connection Chapter 19 Network Configuration 143 ip
122. OWTO Kernel HOWTO html or in the Makefile in usr src linux 2 4 By default usr src linux 2 4 Makefile includes the word custom at the end of the line beginning with EXTRAVERSION Appending the string allows the system to have the old working kernel and the new kernel version 2 4 21 1 1931 2 399 entcustom on the system at the same time If the system contains more than one custom kernel a good method is to append the date at the end or another identifier Appendix A Building a Custom Kernel 317 8 For the x86 and AMD64 architectures build the kernel with make bzImage For the Itanium architecture build the kernel with make compressed For the S 390 and zSeries architectures build the kernel with make image For the iSeries and pSeries architectures build the kernel with make boot 9 Build any modules configured with make modules 10 Use the command make modules_install to install the kernel modules even if nothing was actually built Notice the underscore _ in the command This installs the kernel mod ules into the directory path 1ib modules lt KERNELVERSION gt kernel drivers where KERNELVERSION is the version specified in the Makefile In this example it would be lib modules 2 4 21 1 1931 2 399 entcustom kernel drivers 11 Use make install to copy the new kernel and its associated files to the proper directories In addition to installing the kernel files in the boot directory this command also executes the
123. P means it is encrypted For example 17 13 20 617872 pinky example com gt ijin example com AH spi 0x0aaa749f seq 0x335 ESP spi 0x0ec0441le seq 0x335 DF 19 14 4 Starting and Stopping the Connection If the IPsec connection was not configured to activate on boot start and stop it as root via the command line To start the connection execute the following command as root on each host for host to host IPsec or each IPsec router for network to network IPsec replace lt ipsec nick gt with the one word nickname configured earlier such as ipsec0 sbin ifup lt ipsec nick gt To stop the connection execute the following command as root on each host for host to host IPsec or each IPsec router for network to network IPsec replace lt ipsec nick gt with the one word nickname configured earlier such as ipsec0 sbin ifdown lt ipsec nick gt 19 15 Saving and Restoring the Network Configuration The command line version of Network Administration Tool can be used to save the system s network configuration to a file This file can then be used to restore the network setting to a Red Hat Enterprise Linux system This feature can be used as part of an automated backup script to save the configuration before upgrading or reinstalling or to copy the configuration to a different Red Hat Enterprise Linux system To save or export the system s network configuration to the file tmp network config execute the following co
124. Recovery for instructions on booting into rescue mode When prompted to mount the file system select Skip Alternately if the drive does not contain any partitions in use you can unmount them and turn off all the swap space on the hard drive with the swapof f command 2 At a shell prompt as root execute the following command to make sure the swap partition is disabled where dev hdb2 is the swap partition swapoff dev hdb2 3 Remove its entry from etc fstab 4 Remove the partition using parted Chapter 2 Swap Space 7 Ata shell prompt as root type the command parted dev hdb where dev hdb is the device name for the hard drive with the swap space to be removed At the parted prompt type print to view the existing partitions and determine the minor number of the swap partition you wish to delete Atthe parted prompt type rm MINOR where MINOR is the minor number of the parti tion you want to remove A waming Changes take effect immediately you must type the correct minor number Type quit to exit parted To remove a swap file At a shell prompt as root execute the following command to disable the swap file where swapfile is the swap file swapoff swapfile 2 Remove its entry from etc fstab 3 Remove the actual file rm swapfile 2 4 Moving Swap Space To move swap space from one location to another follow the steps for removing swap space and then follow the steps for adding
125. Red Hat Enterprise Linux 3 System Administration Guide 3 redhat Red Hat Enterprise Linux 3 System Administration Guide Copyright 2003 by Red Hat Inc Red Hat Inc 1801 Varsity Drive Raleigh NC 27606 2072 USA Phone 1 919 754 3700 Phone 888 733 4281 Fax 1 919 754 3701 PO Box 13588 Research Triangle Park NC 27709 USA rhel sag EN 3 Print RHI 2003 07 25T17 10 Copyright 2003 by Red Hat Inc This material may be distributed only subject to the terms and conditions set forth in the Open Publication License V1 0 or later the latest version is presently available at http www opencontent org openpub Distribution of substantively modified versions of this document is prohibited without the explicit permission of the copyright holder Distribution of the work or derivative of the work in any standard paper book form for commercial purposes is prohibited unless prior permission is obtained from the copyright holder Red Hat Red Hat Network the Red Hat Shadow Man logo RPM Maximum RPM the RPM logo Linux Library PowerTools Linux Undercover RHmember RHmember More Rough Cuts Rawhide and all Red Hat based trademarks and logos are trademarks or registered trademarks of Red Hat Inc in the United States and other countries Linux is a registered trademark of Linus Torvalds Motif and UNIX are registered trademarks of The Open Group Intel and Pentium are a registered trademarks of Intel Corporation It
126. Root directive within the lt VirtualHost gt directive The default DocumentRoot is var www html The Webmaster email address corresponds to the ServerAdmin directive within the VirtualHost directive This email address is used in the footer of error pages if you choose to show a footer with an email address on the error pages In the Host Information section choose Default Virtual Host IP based Virtual Host or Name based Virtual Host Default Virtual Host You should only configure one default virtual host remember that there is one setup by default The default virtual host settings are used when the requested IP address is not explicitly listed in another virtual host If there is no default virtual host defined the main server settings are used IP based Virtual Host If you choose IP based Virtual Host a window appears to configure the lt VirtualHost gt di rective based on the IP address of the server Specify this IP address in the IP address field To specify more than one IP address separate each IP address with spaces To specify a port use the syntax IP Address Port Use to configure all ports for the IP address Specify the host name for the virtual host in the Server Host Name field 198 Chapter 26 Apache HTTP Server Configuration Name based Virtual Host If you choose Name based Virtual Host a window appears to configure the NameVirtualHost directive based on the host name of the server Specify the IP addres
127. SA private key 1024 bit long modulus REFERT t Pee eee eee e mee ee er eer ee eee eee eee eee eee eee eeeseeeeeeeeeeesesess aE ASE e is 65537 0x10001 Enter pass phrase You now need to type in a passphrase For best security it should contain at least eight characters include numbers and or punctuation and not be a word in a dictionary Also remember that your passphrase is case sensitive Note You need to remember and enter this passphrase every time you start your secure server so do not forget it Re type the passphrase to verify that it is correct Once you have typed it in correctly etc httpd conf ssl key server key containing your key is created Note that if you do not want to type in a passphrase every time you start your secure server you need to use the following two commands instead of make genkey to create the key Use the following command to create your key usr bin openssl genrsa 1024 gt etc httpd conf ssl key server key Then use the following command to make sure the permissions are set correctly for the file chmod go rwx etc httpd conf ssl key server key After you use the above commands to create your key you do not need to use a passphrase to start your secure server Onis Disabling the passphrase feature for your secure server is a security risk It is NOT recommend that you disable the passphrase feature for secure server The problems associated with not using a passphrase are dir
128. Specify which of the NFS FTP or HTTP protocols to use for installa tion Only one may be specified This corresponds to the Select protocol for installation menu in Figure 14 1 Chapter 14 PXE Network Installations 93 D 0 Indicates that it is not a diskless configuration since pxeos can be used to configure a diskless environment as well e s client example com Provide the name of the NFS FTP or HTTP server after the s option This corresponds to the Server field in Figure 14 1 L lt net location gt Provide the location of the installation tree on that server after the L option This corresponds to the Location field in Figure 14 1 e lt os identifer gt Specify the OS identifier which is used as the directory name in the tftpboot linux install directory This corresponds to the Operating system identifier field in Figure 14 1 If FTP is selected as the installation protocol and anonymous login is not available specify a user name and password for login with the following options before lt os identifer gt in the previous command A 0 u lt username gt p lt password gt 14 3 Adding PXE Hosts After configuring the network server the interface as shown in Figure 14 2 is displayed Eile Configure Help Ss f 9 New Properties Delete Hostname operating System lip Address 4 gt Figure 14 2 Add Hosts The next step is to configu
129. The access control files are read each time a user tries to add or delete a cron task The root user can always use cron regardless of the usernames listed in the access control files Chapter 37 Automated Tasks 269 If the file cron allow exists only users listed in it are allowed to use cron and the cron deny file is ignored If cron allow does not exist users listed in cron deny are not allowed to use cron 37 1 3 Starting and Stopping the Service To start the cron service use the command sbin service crond start To stop the service use the command sbin service crond stop It is recommended that you start the service at boot time Refer to Chapter 21 Controlling Access to Services for details on starting the cron service automatically at boot time 37 2 At and Batch While cron is used to schedule recurring tasks the at command is used to schedule a one time task at a specific time The bat ch command is used to schedule a one time task to be executed when the systems load average drops below 0 8 To use at or batch the at RPM package must be installed and the atd service must be running To determine if the package is installed use the rpm q at command To determine if the service is running use the command sbin service atd status 37 2 1 Configuring At Jobs To schedule a one time job at a specific time type the command at time where time is the time to execute the command The argument t ime can be one o
130. This chapter discusses the basics of using NFS For more detailed information refer to the following resources 23 4 1 Installed Documentation The man pages for nfsd mountd exports auto master and autofs in manual sections 5 and 8 These man pages show the correct syntax for the NFS and autofs configuration files 23 4 2 Useful Websites http nfs sourceforge net the NFS webpage includes links to the mailing lists and FAQs http www tldp org HOWTO NFS HOWTO index html The Linux NFS HOWTO from the Linux Documentation Project 23 4 3 Related Books Managing NFS and NIS Services by Hal Stern O Reilly amp Associates Inc 170 Chapter 23 Network File System NFS redhat Chapter 24 Samba Samba uses the SMB protocol to share files and printers across a network connection Operating systems that support this protocol include Microsoft Windows OS 2 and Linux The Red Hat Enterprise Linux 3 kernel contains Access Control List ACL support for ext3 file systems If the Samba server shares an ext3 file system with ACLs enabled for it and the kernel on the client system contains support for reading ACLs from ext3 file systems the client automatically recognizes and uses the ACLs Refer to Chapter 8 Access Control Lists for more information on ACLs 24 1 Why Use Samba Samba is useful if you have a network of both Windows and Linux machines Samba allows files and printers to be shared by all
131. To activate the device select it from the device list and click the Activate button If the system is configured to activate the device when the computer starts the default this step does not have to be performed again 19 5 Establishing an xDSL Connection DSL stands for Digital Subscriber Lines There are different types of DSL such as ADSL IDSL and SDSL The Network Administration Tool uses the term xDSL to mean all types of DSL connections Some DSL providers require that the system is configured to obtain an IP address through DHCP with an Ethernet card Some DSL providers require you to configure a PPPoE Point to Point Protocol over Ethernet connection with an Ethernet card Ask your DSL provider which method to use If you are required to use DHCP refer to Section 19 2 Establishing an Ethernet Connection to config ure your Ethernet card If you are required to use PPPoE follow these steps Chapter 19 Network Configuration 129 1 Click the Devices tab 2 Click the New button 3 Select xDSL connection from the Device Type list and click Forward 4 If your Ethernet card is in the hardware list select the Ethernet Device from the pulldown menu from the page shown in Figure 19 8 Otherwise the Select Ethernet Adapter window appears Note The installation program detects supported Ethernet devices and prompts you to configure them If you configured any Ethernet devices during the installation they are displayed in
132. To add a Samba user select Preferences gt Samba Users from the pulldown menu and click the Add User button On the Create New Samba User window select a Unix Username from the list of existing users on the local system If the user has a different username on a Windows machine and will be logging into the Samba server from the Windows machine specify that Windows username in the Windows Username field The Authentication Mode on the Security tab of the Server Settings preferences must be set to User for this option to work Also configure a Samba Password for the Samba User and confirm the Samba Password by typing it again Even if you select to use encrypted passwords for Samba it is recommended that the Samba passwords for all users are different from their system passwords To edit an existing user select the user from the list and click Edit User To delete an existing Samba user select the user and click the Delete User button Deleting a Samba user does not delete the associated system user account The users are modified immediately after clicking the OK button 24 2 1 3 Adding a Share Basic Access Directory docs project Browse Description Shared Docs Project Basic Permissions Read only Read Write 3 Cancel amp OK Figure 24 5 Adding a Share To add a share click the Add button The Basic tab configures the following options Directo
133. a different computer or install some RPM packages from a shared network location for example You will also see the following message The rescue environment will now attempt to find your Red Hat Linux installation and mount it under the directory mnt sysimage You can then make any changes required to your system If you want to proceed with this step choose Continue You can also choose to mount your file systems read only instead of read write by choosing Read only If for some reason this process fails you can choose Skip and this step will be skipped and you will go directly toa command shell If you select Continue it attempts to mount your file system under the directory mnt sysimage If it fails to mount a partition it notifies you If you select Read Only it attempts to mount your file system under the directory mnt sysimage but in read only mode If you select Skip your file system is not mounted Choose Skip if you think your file system is corrupted Once you have your system in rescue mode a prompt appears on VC virtual console 1 and VC 2 use the Ctrl AIlt F1 key combination to access VC 1 and Ctrl AIt F2 to access VC 2 1 Refer to the Red Hat Enterprise Linux Installation Guide for more details 1 Refer to the Red Hat Enterprise Linux Installation Guide for more details Chapter 11 Basic System Recovery 81 sh 2 05b If you selected Continue to mount your partitions automaticall
134. a print job You can not cancel print jobs that were started by other users unless you are logged in as root on the machine to which the printer is attached You can also print a file directly from a shell prompt For example the command lpr sample txt will print the text file sample txt The print filter determines what type of file it is and converts it into a format the printer can understand 36 13 Sharing a Printer The Printer Configuration Tool s ability to share configuration options can only be used if you are using the CUPS printing system Allowing users on a different computer on the network to print to a printer configured for your system is called sharing the printer By default printers configured with the Printer Configuration Tool are not shared To share a configured printer start the Printer Configuration Tool and select a printer from the list Then select Action gt Sharing from the pulldown menu f Note If a printer is not selected Action gt Sharing only shows the system wide sharing options normally shown under the General tab On the Queue tab select the option to make the queue available to other users Chapter 36 Printer Configuration 265 Queue General 7 This queue is available to other computers Allowed hosts Add Edit Remove T Help 3 Cancel 2 OK Figure 36 17 Queue Options After selecting to sh
135. able or disable the iptables and ipchains services 150 Chapter 20 Basic Firewall Configuration redhat Chapter 21 Controlling Access to Services Maintaining security on your system is extremely important One way to manage security on your system is to manage access to system services carefully Your system may need to provide open access to particular services for example httpd if you are running a Web server However if you do not need to provide a service you should turn it off to minimize your exposure to possible bug exploits There are several different methods for managing access to system services Decide which method of management to use based on the service your system s configuration and your level of Linux expertise The easiest way to deny access to a service is to turn it off Both the services managed by xinetd discussed later in this section and the services in the etc rc d init d hierarchy also known as SysV services can be configured to start or stop using three different applications Services Configuration Tool a graphical application that displays a description of each service displays whether each service is started at boot time for runlevels 3 4 and 5 and allows services to be started stopped and restarted e ntsysv a text based application that allows you to configure which services are started at boot time for each runlevel Changes do not take effect immediately for non xinet
136. about home directories UIDs or shells So if you enable it you will need to make users accounts known to the workstation by enabling LDAP NIS or Hesiod or by using the usr sbin useradd command to make their accounts known to the workstation To use this option you must have the pam_smb package installed smbservers The name of the server s to use for SMB authentication To specify more than one server separate the names with commas smbworkgroup The name of the workgroup for the SMB servers enablecache Enables the nscd service The nscd service caches information about users groups and various other types of information Caching is especially helpful if you choose to distribute information about users and groups over your network using NIS LDAP or hesiod Chapter 9 Kickstart Installations 43 boot loader required Specifies how the boot loader should be installed and whether the boot loader should be LILO or GRUB This option is required for both installations and upgrades For upgrades if useLilo is not specified and LILO is the current bootloader the bootloader will be changed to GRUB To preserve LILO on upgrades use bootloader upgrade append Specifies kernel parameters To specify multiple parameters separate them with spaces For example bootloader location mbr append hdd ide scsi ide nodma driveorder Specify which drive is first in the BIOS boot order For example
137. accomplished by having the operating system recognize an interface card such as Ethernet ISDN modem or token ring and configuring the interface to connect to the network The Network Administration Tool can be used to configure the following types of network inter faces Ethernet ISDN e modem xDSL e token ring CIPE e wireless devices It can also be used to configure IPsec connections manage DNS settings and manage the etc hosts file used to store additional hostnames and IP address combinations To use the Network Administration Tool you must have root privileges To start the application go to the Main Menu Button on the Panel gt System Settings gt Network or type the command redhat config network at a shell prompt for example in an XTerm or a GNOME terminal If you type the command the graphical version is displayed if X is running otherwise the text based version is displayed To force the text based version to run use the redhat config network tui command To use the command line version execute the command redhat config network cmd help as root to view all the options File Profile Help 4 f BGO x New Edit Copy Delete Activate Deactivate Devices Hardware IPsec DNS Hosts lt j You may configure network devices associated with 3 physical hardware here Multiple logical devices can be J associated with a single piece of hardware
138. ader into the USB port of the computer issue the following command as root where dev sdal is the device name for the media card and dev usbcard is the user defined device name to use devlabel add d dev sdal s dev usbcard automount Chapter 7 User Defined Device Names 29 This commands adds an entry for the mount point to etc sysconfig devlabel and creates a symbolic link from dev usbcard to dev sdal The automount option to devlabe1 specifies that the device should be automatically mounted when devlabe1 restarts if an entry for it is located in etc fstab and if the device exists a device with the same UUID is found The updfstab is a program that scans the IDE and SCSI buses for new devices and adds entries to etc fstab for them if entries do not already exist It also adds entries for USB devices since they appear as SCSI devices Refer to the updfst ab man page for more information When a USB device is inserted hotplug runs the updfstab program which adds an entry to etc fstab for the storage device such as the media card if it exists If a card reader without a card in it is inserted an entry is not added The line added contains the actual device name such as dev sda1 and the kudzu option The kudzu option tells Kudzu that it can remove the line if the device does not exist Since the line is required by devlabel the kudzu option must be removed so the line remains in the file Also change the device name to t
139. al resources 162 OProfile 299 dev profile 309 additional resources 312 configuring 300 separating profiles 303 events sampling rate 302 setting 301 monitoring the kernel 300 opcontrol 300 no vmlinux 300 start 304 vmlinux 300 oprofiled 304 log file 304 oprofpp 306 op_help 302 op_merge 309 op_time 305 op_to_source 308 overview of tools 300 reading data 304 saving data 304 starting 304 unit mask 303 oprofiled See OProfile oprofpp See OProfile oprof_start 310 op_help 302 op_merge See OProfile op_time See OProfile op_to_source See OProfile P Package Management Tool 113 installing packages 114 removing packages 115 packages dependencies 106 determining file ownership with 110 finding deleted files from 110 freshening with RPM 107 installing 104 with Package Management Tool 114 locating documentation for 111 obtaining list of files 111 preserving configuration files 107 querying 108 querying uninstalled 111 removing 106 with Package Management Tool 115 tips 110 upgrading 107 verifying 108 pam_smbpass 176 pam_timestamp 229 parted 15 creating partitions 16 overview 15 removing partitions 18 resizing partitions 19 selecting device 16 table of commands 15 viewing partition table 16 partition table viewing 16 partitions creating 16 formating mkfs 17 labeling e2label 18 making mkpart 17 removing 18 resizing 19 view
140. all clients and options can be declared for each client system The configuration file can contain any extra tabs or blank lines for easier formatting The keywords are case insensitive and lines beginning with a hash mark are considered comments Two DNS update schemes are currently implemented the ad hoc DNS update mode and the interim DHCP DNS interaction draft update mode If and when these two are accepted as part of the IETF standards process there will be a third mode the standard DNS update method The DHCP server must be configured to use one of the two current schemes Version 3 0b2pl11 and previous version used the ad hoc mode however it has been deprecated To keep the same behavior add the following line to the top of the configuration file ddns update style ad hoc To use the recommended mode add the following line to the top of the configuration file ddns update style interim Refer to the dhcpd conf man page for details about the different modes 182 Chapter 25 Dynamic Host Configuration Protocol DHCP There are two types of statements in the configuration file e Parameters state how to perform a task whether to perform a task or what network configuration options to send to the client e Declarations describe the topology of the network describe the clients provide addresses for the clients or apply a group of parameters to a group of declarations Some parameters must start with the o
141. all configuration 71 installation method selection 64 interactive 64 keyboard 63 language 63 language support 64 mouse 63 network configuration 70 package selection 75 partitioning 67 software RAID 68 preview 63 reboot 64 root password 64 encrypt 64 saving 78 text mode installation 64 time zone 63 X configuration 72 kickstart file include 55 post 57 pre 56 auth 40 authconfig 40 autopart 40 autostep 40 bootloader 43 CD ROM based 59 clearpart 44 cmdline 44 creating 40 device 44 diskette based 58 driverdisk 45 firewall 45 firstboot 46 format of 39 include contents of another file 55 install 46 installation methods 46 interactive 47 keyboard 47 lang 47 langsupport 47 logvol 48 mouse 48 network 49 network based 59 60 options 40 package selection specification 55 part 50 partition 50 post installation configuration 57 pre installation configuration 56 raid 51 reboot 52 rootpw 52 skipx 53 text 53 timezone 53 upgrade 53 volgroup 54 what it looks like 39 xconfig 53 zerombr 54 kickstart installations 39 CD ROM based 59 diskette based 58 file format 39 file locations 58 installation tree 59 LVM 48 network based 59 60 starting 60 from a boot CD ROM 60 from a boot diskette 60 from CD ROM 1 with a diskette 60 Kudzu 29 L LDAP 220 221 loading kernel modules 285 log files 273
142. alled Since RPM performs intelligent upgrading of packages with configuration files you may see a mes sage like the following saving etc foo conf as etc foo conf rpmsave This message means that your changes to the configuration file may not be forward compatible with the new configuration file in the package so RPM saved your original file and installed a new one You should investigate the differences between the two configuration files and resolve them as soon as possible to ensure that your system continues to function properly Upgrading is really a combination of uninstalling and installing so during an RPM upgrade you can encounter uninstalling and installing errors plus one more If RPM thinks you are trying to upgrade to a package with an older version number the output is similar to the following package foo 2 0 1 which is newer than foo 1 0 1 is already installed To cause RPM to upgrade anyway use the oldpackage option rpm Uvh oldpackage foo 1 0 1 i386 rpm 16 2 5 Freshening Freshening a package is similar to upgrading one Type the following command at a shell prompt rpm Fvh foo 1 2 1 i386 rpm RPM s freshen option checks the versions of the packages specified on the command line against the versions of packages that have already been installed on your system When a newer version of an already installed package is processed by RPM s freshen option it is upgraded to the newer version However RP
143. ample com Your non secure server can be accessed using an URL similar to the following http server example com 212 Chapter 27 Apache HTTP Secure Server Configuration The standard port for secure Web communications is port 443 The standard port for non secure Web communications is port 80 The secure server default configuration listens on both of the two standard ports Therefore do not need to specify the port number in a URL the port number is assumed However if you configure your server to listen on a non standard port for example anything other than 80 or 443 you must specify the port number in every URL which is intended to connect to the server on the non standard port For example you may have configured your server so that you have a virtual host running non secured on port 12331 Any URLs intended to connect to that virtual host must specify the port number in the URL The following URL example attempts to connect to a non secure server listening on port 12331 http server example com 12331 27 11 Additional Resources Refer to Section 26 7 Additional Resources for additional references about the Apache HTTP Server 27 11 1 Useful Websites http www redhat com mailman listinfo redhat secure server The redhat secure server mailing list You can also subscribe to the redhat secure server mailing list by emailing lt redhat secure server request redhat com gt and include the word subscribe in the subject
144. amples The third column is unused and the fourth is the name of the executable Refer to the op_time man page for a list of available command line options such as the r option used to sort the output from the executable with the largest number of samples to the one with the smallest number of samples The c option is also useful for specifying a counter number 306 Chapter 43 OProfile 43 5 2 Using oprofpp To retrieve more detailed information about a specific executable use oprofpp oprofpp lt mode gt lt executable gt lt executable gt must be the full path to the executable to be analyzed lt mode gt must be one of the following 1 List sample data by symbols For example the following is part of the output from running the command oprofpp 1 usr X11R6 bin XFree86 vma samples symbol name 08195d10 4 3 0303 miComputeCompositeClip 080b9180 5 3 78788 Dispatch 080cdce0 5 3 78788 FreeResource 080ce4a0 5 3 78788 LegalNewID 080ce640 5 3 78788 SecurityLookupIDByClass 080dd470 9 6 81818 WaitForSomething 080e1360 12 9 09091 StandardReadRequestFromClient The first column is the starting virtual memory address vma The second column is the number of samples for the symbol The third column is the percentage of samples for this symbol relative to the overall samples for the executable and the fourth column is the symbol name To sort the output from the largest number of samples to the smallest reverse order use
145. an XTerm or GNOME Terminal File Help f G New Properties Delete Add Record Save gt 8 0 0 127 in addr arpa Figure 28 1 Domain Name Service Configuration Tool The Domain Name Service Configuration Tool configures the default zone directory to be var named All zone files specified are relative to this directory The Domain Name Service Configuration Tool also includes basic syntax checking when values are entered For example if a valid entry is an IP address only numbers and periods are allowed in the text area The Domain Name Service Configuration Tool allows for the addition of a forward master zone a reverse master zone and a slave zone After adding the zones they can be edited or deleted from the main window as shown in Figure 28 1 After adding editing or deleting a zone click the Save button or select File gt Save to write the etc named conf configuration file and all the individual zone files in the var named directory Saving changes also causes the named service to reload the configuration files Selecting File gt Quit saves the changes before quitting the application 214 Chapter 28 BIND Configuration 28 1 Adding a Forward Master Zone To add a forward master zone also known as a primary master click the New button select Forward Master Zone and enter the domain name for the master zone in the Domain name text area A new window as shown in Figure 28 2 appears with the
146. and create the specified file end mb system move minor num start mb end mb Move the partition Name the partition for Mac and PC98 disklabels only Display the partition table rescue Start mb end mb Rescue a lost partition from st art mb to end mb 16 Chapter 5 Managing Disk Storage resize minor num start mb end mb Resize the partition from st art mb to end mb rm minor num Remove the partition select device Select a different device to configure set minor num flag state Set the flag on a partition st ate is either on or off Table 5 1 parted commands 5 1 Viewing the Partition Table After starting parted type the following command to view the partition table print A table similar to the following appears Disk geometry for dev hda 0 000 9765 492 megabytes Disk label type msdos Minor Start End Type Filesystem Flags T 0 031 101 975 primary ext3 boot 2 101 975 611 850 primary linux swap 3 611 851 760 891 primary ext3 4 760 891 9758 232 extended lba 5 760 922 9758 232 logical ext3 The first line displays the size of the disk the second line displays the disk label type and the re maining output shows the partition table In the partition table the Minor number is the partition number For example the partition with minor number 1 corresponds to dev hdal The Start and End values are in megabytes The Type is one of primary extended or logical The Filesystem is the file system type which ca
147. anium and Celeron are trademarks of Intel Corporation AMD Opteron Athlon Duron and K6 are registered trademarks of Advanced Micro Devices Inc Netscape is a registered trademark of Netscape Communications Corporation in the United States and other countries Windows is a registered trademark of Microsoft Corporation SSH and Secure Shell are trademarks of SSH Communications Security Inc FireWire is a trademark of Apple Computer Corporation IBM AS 400 OS 400 RS 6000 S 390 and zSeries are registered trademarks of International Business Machines Corporation eServer iSeries and pSeries are trademarks of International Business Machines Corporation All other trademarks and copyrights referred to are the property of their respective owners The GPG fingerprint of the security redhat com key is CA 20 86 86 2B D6 9D FC 65 F6 EC C4 21 91 80 CD DB 42 A6 0E Table of Contents Ti tO MU CHI ON sec ieees seascsee siasancinezcchessevensveceessseceasuccsucecs savburact eccsasuaentesescccscesteesedencvaseasbocvicssaseieesesesssesccsees i 1 Changes to This Manual 2 Document Conventions 3 More 10 COME nenir sre teeren ersa ee L ar SEEN EATA E ENSE EEEE DENS 3 1 Send in Your Feedbac kisoi rye eie E enter A EE EEE a v 4 Sign Up for SUPPO ane esia E E E E AA E EEA A RROA v T File Systems ssssscsssssssssescsssssssssssssssesssesessesssssesecsssassssessvscesesesessesesssessssssesessesesasesesessesesessseeseseses i l ThE EXt
148. ant to install a boot loader select Do not install a boot loader If you choose not to install a boot loader make sure you create a boot diskette or have another way to boot such as a third party boot loader your system If you choose to install a boot loader you must also choose which boot loader to install GRUB or LILO and where to to install the boot loader the Master Boot Record or the first sector of the boot partition Install the boot loader on the MBR if you plan to use it as your boot loader If you are using a different boot loader install LILO or GRUB on the first sector of the boot partition and configure the other boot loader to boot Red Hat Enterprise Linux To pass any special parameters to the kernel to be used when the system boots enter them in the Kernel parameters text field For example if you have an IDE CD ROM Writer you can tell the kernel to use the SCSI emulation driver that must be loaded before using cdrecord by configuring hdd ide scsi as a kernel parameter where hdd is the CD ROM device If you choose GRUB as the boot loader you can password protect it by configuring a GRUB password Select Use GRUB password and enter a password in the Password field Type the same password in the Confirm Password text field To save the password as an encrypted password in the file select Encrypt GRUB password If the encryption option is selected when the file is saved the plain text password that you typed will be en
149. any My Company Ltd Test Company Organizational Unit Name eg section Testing Common Name your name or server s hostname test example com Email Address admin example com Please enter the following extra attributes to be sent with your certificate request A challenge password An optional company name The default answers appear in brackets immediately after each request for input For example the first information required is the name of the country where the certificate will be used shown like the following Country Name 2 letter code GB The default input in brackets is GB To accept the default press Enter or fill in your country s two letter code 210 Chapter 27 Apache HTTP Secure Server Configuration You have to type in the rest of the values All of these should be self explanatory but you need to follow these guidelines e Do not abbreviate the locality or state Write them out for example St Louis should be written out as Saint Louis e If you are sending this CSR to a CA be very careful to provide correct information for all of the fields but especially for the Organization Name and the Common Name CAs check the information provided in the CSR to determine whether your organization is responsible for what you provided as the Common Name CAs rejects CSRs which include information they perceive as invalid For Common Name make sure you type in the real name of your
150. ap dev hdb2 4 To enable the swap partition immediately type the following command swapon dev hdb2 5 To enable it at boot time edit etc fstab to include dev hdb2 swap swap defaults 0 0 The next time the system boots it enables the new swap partition 6 After adding the new swap partition and enabling it verify it is enabled by viewing the output of the command cat proc swaps or free To add a swap file Determine the size of the new swap file in megabytes and multiple by 1024 to determine the block size For example the block size of a 64 MB swap file is 65536 2 At a shell prompt as root type the following command with count being equal to the desired block size dd if dev zero of swapfile bs 1024 count 65536 3 Setup the swap file with the command mkswap swapfile 4 To enable the swap file immediately but not automatically at boot time swapon swapfile 5 To enable it at boot time edit etc fstab to include swapfile swap swap defaults 0 0 The next time the system boots it enables the new swap file 6 After adding the new swap file and enabling it verify it is enabled by viewing the output of the command cat proc swaps or free 2 3 Removing Swap Space To remove a swap partition 1 The hard drive can not be in use partitions can not be mounted and swap space can not be enabled The easiest way to achieve this it to boot your system in rescue mode Refer to Chapter 11 Basic System
151. are easy to upgrade and verify For example when the kernel RPM package distributed by Red Hat Inc is installed an initrd image is created thus it is not necessary to use the mkinitrd command after installing a different kernel It also modifies the boot loader configuration file to include the new kernel waming Building a custom kernel is not supported by the Red Hat Installation Support Team For more in formation on building a custom kernel from the source code refer to Appendix A Building a Custom Kernel 39 1 Overview of Kernel Packages Red Hat Enterprise Linux contains the following kernel packages some may not apply to your archi tecture kernel contains the kernel and the following key features Uniprocessor support for x86 and Athlon systems can be run on a multi processor system but only one processor is utilized Multi processor support for all other architectures For x86 systems only the first 4 GB of RAM is used use the kerne1 hugemem package for x86 system with over 4 GB of RAM e kernel hugemem only for i686 systems In addition to the options enabled for the kernel package The key configuration options are as follows Support for more than 4 GB of RAM up to 16 GB for x86 PAE Physical Address Extension or 3 level paging on x86 processors that support PAE Support for multiple processors 4GB 4GB split 4GB of virtual address space for kernel and almost 4GB for each
152. are list on the Hardware tab 5 If you selected Other Wireless Card the Select Ethernet Adapter window appears Select the manufacturer and model of the Ethernet card and the device If this is the first Ethernet card for the system select eth0 if this is the second Ethernet card for the system select eth1 and so on The Network Administration Tool also allows the user to configure the resources for the wireless network interface card Click Forward to continue 6 On the Configure Wireless Connection page as shown in Figure 19 14 configure the settings for the wireless device Configure Wireless Connection H Mode Auto v Network Name SSID Auto Specified i Dej Channel 1 E Transmit Rate Auto v Key use Ox for hex 3 Cancel lt d Back D Foward Figure 19 14 Wireless Settings 7 On the Configure Network Settings page choose between DHCP and static IP address You may specify a hostname for the device If the device receives a dynamic IP address each time the network is started do not specify a hostname Click Forward to continue 8 Click Apply on the Create Wireless Device page After configuring the wireless device it appears in the device list as shown in Figure 19 15 Chapter 19 Network Configuration 135 File Profile Help arf Bg xX New Edit Copy Delete Activate Deactivate Devices Hardware IPsec DNS Hosts
153. are the queue by default all hosts are allowed to print to the shared printer Allowing all systems on the network to print to the queue can be dangerous especially if the system is directly connected to the Internet It is recommended that this option be changed by selecting the All hosts entry and clicking the Edit button to display the window shown in Figure 36 18 If you have a firewall configured on the print server it must be able to send and receive connections on the incoming UDP port 631 If you have a firewall configured on the client the computer sending the print request it must be allowed to send and accept connections on port 631 Choose which other computers may use this queue All hosts Network devices etho eth Network address n O Single IP address T Heip 2 Cancel OK Figure 36 18 Allowed Hosts The General tab configures settings for all printers including those not viewable with the Printer Configuration Tool There are two options Automatically find remote shared queues Selected by default this option enables IPP brows ing which means that when other machines on the network broadcast the queues that they have the queues are automatically added to the list of printers available to the system no additional config uration is required for a printer found from IPP browsing This option does not automatically share the printers configured on the
154. as 10 3 0 0 16 Order Options Let all hosts access this directory Options Process Deny list before Allow list ExecCGl Process Allow list before Deny list FollowSymLinks Includes Deny List IncludesNOEXEC z Indexes Deny access from all hosts C Muttiviews Deny hosts from SymLinks lfOwnerMatch Allow List Allow access from all hosts Allow hosts from 192 168 1 0 255 255 255 0 Let htaccess files override directory options Directory var www html testing T Help 2 OK 3 Cancel Figure 26 7 Directory Settings If you check the Let htaccess files override directory options the configuration directives in the htaccess file take precedence 26 3 Virtual Hosts Settings You can use the HTTP Configuration Tool to configure virtual hosts Virtual hosts allow you to run different servers for different IP addresses different host names or different ports on the same machine For example you can run the website for http www example com and http www anotherexample com on the same Web server using virtual hosts This option corresponds to the lt VirtualHost gt directive for the default virtual host and IP based virtual hosts It corresponds to the lt NameVirtualHost gt directive for a name based virtual host The directives set for a virtual host only apply to that particular virtual host If a directive is set server wide using the Edit Default Settings button and not
155. ast step is assigning the disk quotas with the edquota command To configure the quota for a user as root in a shell prompt execute the command edquota username Perform this step for each user who needs a quota For example if a quota is enabled in etc fstab for the home partition dev hda3 and the command edquota testuser is executed the follow ing is shown in the editor configured as the default for the system Disk quotas for user testuser uid 501 Filesystem blocks soft hard inodes soft hard dev hda3 440436 0 0 37418 0 0 Chapter 6 Implementing Disk Quotas 23 Note The text editor defined by the EDITOR environment variable is used by edquota To change the editor set the EDITOR environment variable to the full path of the editor of your choice The first column is the name of the file system that has a quota enabled for it The second column shows how many blocks the user is currently using The next two columns are used to set soft and hard block limits for the user on the file system The inodes column shows how many inodes the user is currently using The last two columns are used to set the soft and hard inode limits for the user on the file system A hard limit is the absolute maximum amount of disk space that a user or group can use Once this limit is reached no further disk space can be used The soft limit defines the maximum amount of disk space that can be used However unlike the hard limit the soft limi
156. ates for more details about certificates To make your own self signed certificate first create a random key using the instructions provided in Section 27 6 Generating a Key Once you have a key make sure you are in the usr share ssl certs directory and type the following command make testcert The following output is shown and you are prompted for your passphrase unless you generated a key without a passphrase umask 77 usr bin openssl req new key etc httpd conf ssl key server key x509 days 365 out etc httpd conf ssl crt server crt Using configuration from usr share ssl openssl cnf Enter pass phrase After you enter your passphrase or without a prompt if you created a key without a passphrase you are asked for more information The computer s output and a set of inputs looks like the following provide the correct information for your organization and host Chapter 27 Apache HTTP Secure Server Configuration 211 You are about to be asked to enter information that will be incorporated into your certificate request What you are about to enter is what is called a Distinguished Name or a DN There are quite a few fields but you can leave some blank For some fields there will be a default value If you enter the field will be left blank Country Name 2 letter code GB US State or Province Name full name Berkshire North Carolina Locality Name eg city Newbury Raleigh Organization Name
157. ause of PXELINUX which is part of the syslinux package The following steps must be performed to prepare for a PXE installation 1 Configure the network NFS FTP HTTP server to export the installation tree 2 Configure the files on the t ftp server necessary for PXE booting 3 Configure which hosts are allowed to boot from the PXE configuration 4 Start the t ftp service 5 Configure DHCP 6 Boot the client and start the installation 14 1 Setting up the Network Server First configure an NFS FTP or HTTP server to export the entire installation tree for the version and variant of Red Hat Enterprise Linux to be installed Refer to the section Preparing for a Network Installation in the Red Hat Enterprise Linux Installation Guide for detailed instructions 14 2 PXE Boot Configuration The next step is to copy the files necessary to start the installation to the t ftp server so they can be found when the client requests them The t ftp server is usually the same server as the network server exporting the installation tree To copy these files run the Network Booting Tool on the NFS FTP or HTTP server A separate PXE server is not necessary For the command line version of these instructions refer to Section 14 2 1 Command Line Configu ration To use the graphical version of the Network Booting Tool you must be running the X Window System have root privileges and have the redhat config netboot RPM package installed
158. be asked to provide basic information for adding a new print queue You will be able to edit the more advanced options afterwards Nothing will be done to your settings until you hit Apply on the last screen s Help Cancel 4 Back gt Forward Figure 36 2 Adding a Printer In the window shown in Figure 36 3 enter a unique name for the printer in the Name text field The printer name cannot contain spaces and must begin with a letter The printer name may contain letters numbers dashes and underscores _ Optionally enter a short description for the printer which can contain spaces Chapter 36 Printer Configuration 251 Queue name Please enter a name for this queue Choose a short name that begins with a letter and contains no spaces Name printer About If you like you can enter a description of the printer to help you identify it more easily Short description T Heip Cancel lt d Back Figure 36 3 Selecting a Queue Name After clicking Forward Figure 36 4 appears Select Locally connected from the Select a queue type menu and select the device The device is usually dev 1p0 for a parallel printer or dev usb 1p0 for a USB printer If no devices appear in the list click Rescan devices to rescan the computer or click Custom device to specify it manually Click Forward to continue Select a queue type Locally
159. because it needs to bind to a port below 1024 Ports below 1024 are reserved for system use so they can not be used by anyone but root Once the server has attached itself to its port however it hands the process off to the apache user before it accepts any connection requests The Group value corresponds to the Group directive The Group directive is similar to the User directive Group sets the group under which the server will answer requests The default group is also apache 26 5 Performance Tuning Click on the Performance Tuning tab to configure the maximum number of child server processes you want and to configure the Apache HTTP Server options for client connections The default settings for these options are appropriate for most situations Altering these settings may affect the overall performance of your Web server Main Virtual Hosts Server Performance Tuning Servers gt Max Number of Connections 150 Connections gt Connection Timeout 300 Allow unlimited requests per connection Max requests per connection 100 Requests per Connection O Allow Persistent Connections Timeout for next Connection 15 OK 3 Cancel T Heip Figure 26 11 Performance Tuning Set Max Number of Connections to the maximum number of simultaneous client requests that the server will handle For each connection a child httpd process is created After this maximum num
160. bel it work e2label dev hda3 work By default the installation program uses the mount point of the partition as the label to make sure the label is unique You can use any label you want 5 2 4 Creating the Mount Point As root create the mount point mkdir work 5 2 5 Add to etc fstab As root edit the etc fstab file to include the new partition The new line should look similar to the following LABEL work work ext3 defaults 12 The first column should contain LABEL followed by the label you gave the partition The second column should contain the mount point for the new partition and the next column should be the file system type for example ext3 or swap If you need more information about the format read the man page with the command man fstab If the fourth column is the word defaults the partition is mounted at boot time To mount the partition without rebooting as root type the command mount work 5 3 Removing a Partition A waming Do not attempt to remove a partition on a device that is in use Before removing a partition boot into rescue mode or unmount any partitions on the device and turn off any swap space on the device Start parted where dev hda is the device on which to remove the partition Chapter 5 Managing Disk Storage 19 parted dev hda View the current partition table to determine the minor number of the partition to remove print Remove the partition with the comman
161. ber of processes is reached no one else will be able to connect to the Web server until a child server process is freed You can not set this value to higher than 256 without recompiling This option corre sponds to the MaxClients directive Connection Timeout defines in seconds the amount of time that your server will wait for receipts and transmissions during communications Specifically Connection Timeout defines how long your Chapter 26 Apache HTTP Server Configuration 201 server will wait to receive a GET request how long it will wait to receive TCP packets on a POST or PUT request and how long it will wait between ACKs responding to TCP packets By default Connection Timeout is set to 300 seconds which is appropriate for most situations This option corresponds to the TimeOut directive Set the Max requests per connection to the maximum number of requests allowed per persistent connection The default value is 100 which should be appropriate for most situations This option corresponds to the MaxRequest sPerChild directive If you check the Allow unlimited requests per connection option the MaxKeepAliveRequests directive to 0 and unlimited requests are allowed If you uncheck the Allow Persistent Connections option the KeepAlive directive is set to false If you check it the KeepAlive directive is set to true and the KeepAliveTimeout directive is set to the number that is selected as the Timeout for next Connection value This
162. bootloader driveorder sda hda location Specifies where the boot record is written Valid values are the following mbr the default partition installs the boot loader on the first sector of the partition containing the kernel or none do not install the boot loader password If using GRUB sets the GRUB boot loader password the one specified with this option This should be used to restrict access to the GRUB shell where arbitrary kernel options can be passed md5pass If using GRUB similar to password except the password should already be encrypted useLilo Use LILO instead of GRUB as the boot loader linear If using LILO use the 1inear LILO option this is only for backward compatibility and linear is now used by default nolinear If using LILO use the nolinear LILO option linear is the default lba32 If using LILO force use of lba32 mode instead of auto detecting upgrade Upgrade the existing boot loader configuration preserving the old entries This option is only available for upgrades 44 Chapter 9 Kickstart Installations clearpart optional Removes partitions from the system prior to creation of new partitions By default no partitions are removed Note If the clearpart command is used then the onpart command cannot be used on a logical partition all Erases all partitions from the system drives Specifies which drives to clear parti
163. bootp class pxeclients Chapter 14 PXE Network Installations 95 match if substring option vendor class identifier 0 9 PXEClient next server lt server ip gt filename linux install pxelinux 0 The IP address that follows the next server option should be the IP address of the t ftp server 14 6 Adding a Custom Boot Message Optionally modify t ftpboot linux install msgs boot msg to use a custom boot message 14 7 Performing the PXE Installation For instructions on how to configure the network interface card with PXE support to boot from the network consult the documentation for the NIC It varies slightly per card After the system boots the installation program refer to the Red Hat Enterprise Linux Installation Guide 96 Chapter 14 PXE Network Installations redhat Chapter 15 Diskless Environments Some networks require multiple systems with the same configuration They also require that these systems be easy to reboot upgrade and manage One solution is to use a diskless environment in which most of the operating system which can be read only is shared from a central server between the clients and the individual clients have their own directories on the central server for the rest of the operating system which must be read write Each time the client boots it mounts most of the OS from the NFS server as read only and another directory as read write Each client has its own read write dir
164. bpass 176 reasons for using 171 share connecting to via the command line 178 connecting to with Nautilus 177 mounting 178 smbclient 178 starting the server 176 status of the server 176 stopping the server 176 syncing passwords with passwd 176 with Windows NT 4 0 2000 ME and XP 175 scp See OpenSSH secure server accessing 211 books 212 certificate authorities 207 choosing a CA 207 creation of request 209 moving it after an upgrade 206 pre existing 205 self signed 210 test vs signed vs self signed 206 testing 211 connecting to 211 explanation of security 205 installing 203 key generating 207 packages 203 port numbers 211 providing a certificate for 205 security explanation of 205 upgrading from 206 URLs 211 URLs for 211 websites 212 security 151 security level 327 See Security Level Configuration Tool Security Level Configuration Tool iptables service 149 trusted devices 148 trusted services 148 sendmail 289 services controlling access to 151 Services Configuration Tool 153 setfacl 32 Setup Agent via Kickstart 46 sftp See OpenSSH shadow passwords 221 shutdown disablingCtrlAltDel 227 single user mode 81 SMB 171 222 smb conf 171 smbclient 178 smbstatus 177 Software RAID See RAID ssh See OpenSSH ssh add 162 ssh agent 162 with GNOME 161 star 33 striping RAID fundamentals 9 swap space 5 adding 5 explanation of 5 moving 7 recomme
165. c CA See secure server chage command forcing password expiration with 243 chkconfig 155 CIPE connection See network configuration color depth 237 command line options printing from 264 configuration console access 227 NFS 163 console making files accessible from 228 console access configuring 227 defining 228 disabling 228 disabling all 228 320 enabling 229 conventions document ii Cron 267 additional resources 271 configuration file 267 example crontabs 268 user defined tasks 268 crontab 267 CtrlAltDel shutdown disabling 227 CUPS 249 D date configuration 231 dateconfig See Time and Date Properties Tool devel package 204 device names user defined 27 devlabel 27 add 27 automount 28 configuration file 29 hotplug 28 printid 28 remove 28 restart 29 df 296 DHCP 181 additional resources 187 client configuration 186 command line options 185 connecting to 186 dhcpd conf 181 dhcpd leases 184 dhcrelay 185 diskless environment 94 98 global parameters 182 group 183 options 182 PXE installations 94 98 reasons for using 181 Relay Agent 185 server configuration 181 shared network 182 starting the server 184 stopping the server 184 subnet 182 dhcpd conf 181 dhcpd leases 184 dhcrelay 185 disk quotas 21 additional resources 25 assigning per file system 23 assigning per group 23 assigning per user 22 disabling 25 enabling 21
166. ce on the disk 8 Select Force to be a primary partition if you want the partition to be a primary partition 9 Click OK to return to the main screen Repeat these steps to create as many partitions as needed for your RAID setup Notice that all the partitions do not have to be RAID partitions For example you can configure only the home partition as a software RAID device Once you have all of your partitions created as software RAID partitions follow these steps 84 Chapter 12 Software RAID Configuration 1 Select the RAID button on the Disk Druid main partitioning screen refer to Figure 12 4 2 Figure 12 2 will appear Select Create a RAID device RAID Options Software RAID allows you to combine several disks into a larger RAID device A RAID device can be configured to provide additional speed and reliability compared to using an individual drive For more information on using RAID devices please consult the Red Hat Enterprise Linux AS documentation You currently have 3 software RAID partition s free to use What do you want to do now Create a software RAID partition Create a RAID device default dev mdo Clone a drive to create a RAID device default dev md0 Cancel OK Figure 12 2 RAID Options 3 Next Figure 12 3 will appear where you can make a RAID device Make RAID Device Mount Point home E v X File System Type ext3
167. cified services through the firewall s ssh telnet Ss S http ftp 46 Chapter 9 Kickstart Installations ports You can specify that ports be allowed through the firewall using the port protocol format For example to allow IMAP access through your firewall specify imap tcp Numeric ports can also be specified explicitly for example to allow UDP packets on port 1234 through specify 1234 udp To specify multiple ports separate them by commas firstboot optional Determine whether the Setup Agent starts the first time the system is booted If enabled the firstboot package must be installed If not specified this option is disabled by default enable The Setup Agent is started the first time the system boots disable The Setup Agent is not started the first time the system boots reconfig Enable the Setup Agent to start at boot time in reconfiguration mode This mode enables the language mouse keyboard root password security level time zone and networking configuration options in addition to the default ones install optional Tells the system to install a fresh system rather than upgrade an existing system This is the default mode For installation you must specify the type of installation from one of cdrom harddrive nfs or url for ftp or http installations The install command and the installa tion method command must be on separate lines cdrom Install from
168. ckstart Installations hsync Specifies the horizontal sync frequency of the monitor vsync Specifies the vertical sync frequency of the monitor defaultdesktop Specify either GNOME or KDE to set the default desktop assumes that GNOME Desktop Environment and or KDE Desktop Environment has been installed through packages startxonboot Use a graphical login on the installed system resolution Specify the default resolution for the X Window System on the installed system Valid values are 640x480 800x600 1024x768 1152x864 1280x1024 1400x1050 1600x1200 Be sure to specify a resolution that is compatible with the video card and monitor depth Specify the default color depth for the X Window System on the installed system Valid values are 8 16 24 and 32 Be sure to specify a color depth that is compatible with the video card and monitor volgroup optional Use to create a Logical Volume Management LVM group with the syntax volgroup lt name gt lt partition gt lt options gt The options are as follows noformat Use an existing volume group and do not format it useexisting Use an existing volume group and reformat it Create the partition first create the logical volume group and then create the logical volume For example part pv 01 size 3000 volgroup myvg pv 01 logvol vgname myvg size 2000 name rootvol zerombr optional If zerombr is specified and
169. connected z dev ip0 Rescan devices custom device T Heip Cancel lt d Back Figure 36 4 Adding a Local Printer Next select the printer type Refer to Section 36 7 Selecting the Printer Model and Finishing for details 36 2 Adding an IPP Printer An IPP printer is a printer attached to a different Linux system on the same network running CUPS or a printer configured on another operating system to use IPP By default the Printer Configuration Tool browses the network for any shared IPP printers This option can be changed by selecting Action gt Sharing from the pulldown menu Any networked IPP printer found via CUPS browsing appears in the main window under the Browsed queues category If you have a firewall configured on the print server it must be able to send and receive connections on the incoming UDP port 631 If you have a firewall configured on the client the computer sending the print request it must be allowed to send and accept connections on port 631 252 Chapter 36 Printer Configuration If you disable the automatic browsing feature you can still add a networked IPP printer by clicking the New button in the main Printer Configuration Tool window to display the window in Figure 36 2 Click Forward to proceed In the window shown in Figure 36 3 enter a unique name for the printer in the Name text field The printer name cannot contain spaces and
170. console apps foo 3 Create a PAM configuration file for the foo service in etc pam d An easy way to do this is to start with a copy of the halt service s PAM configuration file and then modify the file if you want to change the behavior cp etc pam d halt etc pam d foo Now when usr bin foois executed consolehelper is called which authenticates the user with the help of usr sbin userhelper To authenticate the user consolehelper asks for the user s password if etc pam d foo is a copy of etc pam d halt otherwise it does precisely what is specified in etc pam d foo and then runs usr sbin foo with root permissions In the PAM configuration file an application can be configured to use the pam_timestamp module to remember cache a successful authentication attempt When an application is started and proper authentication is provided the root password a timestamp file is created By default a successful authentication is cached for five minutes During this time any other application that is configured to use pam_t imestamp and run from the same session is automatically authenticated for the user the user does not have to enter the root password again This module is included in the pam package To enable this feature the PAM configuration file in etc pam d must include the following lines 230 Chapter 30 Console Access auth sufficient lib security pam_timestamp so session optional lib security pam_timestamp s
171. crypted and written to the kickstart file Do not type an already encrypted password and select to encrypt it If you choose LILO as the boot loader choose whether you want to use linear mode and whether you want to force the use of lba32 mode If Upgrade an existing installation is selected on the Installation Method page select Upgrade ex isting boot loader to upgrade the existing boot loader configuration while preserving the old entries Chapter 10 Kickstart Configurator 67 10 4 Partition Information File Help Basic Configuration Partition Information required Installation Method Clear Master Boot Record Boot Loader Options O Do not clear Master Boot Record Partition Information Remove all existing partitions Network Configuration CO Remove existing Linux partitions Authentication Preserve existing partitions Firewall Corian Initialize the disk label X Configuration Do not initialize the disk label Package Selection j Device Mount Point Pre Installation Script Partition Number RAID Volume Bites Sekine Rwy Post Installation Script Add Edit Delete RAID Figure 10 4 Partition Information Select whether or not to clear the Master Boot Record MBR Choose to remove all existing parti tions remove all existing Linux partitions or preserve existing partitions To initialize the disk label to the default for the architecture of the system
172. ctory contains virtual files that represent devices Each virtual file represents a device for the system such as a storage device USB device or printer These virtual files are called device names Device names for IDE devices begin with hd and device names for SCSI devices begin with sd The prefix is followed by a letter starting with a that represents the drive order For example dev hda is the first IDE hard drive dev hdb is the second IDE hard drive dev hdc is the third IDE drive and so on If the device name is followed by a number the number represents the partition number For example dev hdal represents the first partition on the first IDE drive If a hard drive is physically moved to a different location in the machine is removed or fails to initialize some of the device names will change potentially leaving device name references invalid For example as shown in Figure 7 1 if a system has three SCSI hard drives and the second SCSI hard drive is removed dev sdc becomes dev sdb causing any references to dev sdc to become invalid and any references to dev sdb invalid as well since it is a different drive CO dev sda dev sdb dev sdc dev sda dev sdb Figure 7 1 Removing a Hard Drive Every hard drive has a unique identifier associated with it called a UUID To solve the problem of changing device names devlabe1 allows for user defined device names that are associated with these UUIDs A symbolic lin
173. d devlabel printid d lt device gt The symbolic link names must be unique If an existing link already exists when an attempt is made to add it the configuration file is not modified and the following is displayed The file dev work already exists Failure Could not create a symlink To remove a symbolic link from the devlabe1 list use the following command devlabel remove s lt symlink gt The entry is removed from the configuration file and the symbolic link is deleted To determine the status of the devlabe1l symbolic links use the following command devlabel status It returns output similar to the following lrwxrwxrwx 1 root 9 Apr 29 13 20 dev work gt dev hdb1 lrwxrwxrwx 1 root 9 Apr 29 13 41 dev tcf gt dev hdal 7 1 1 Hotplug Devices A program called hotplug performs actions when a system event such as hardware being added or removed takes place while the system is running For example if a USB hard drive or a USB media card reader is attached to the system hotplug notifies users by logging a message in the system log file var log messages and loads the proper kernel modules so the device works When a PCI USB or IEEE 1394 also known as FireWire device is plugged in the hotplug scripts also restart devlabe1 so that the removable storage media receives a user defined device name such as dev usbcard and optionally it can automatically mount the storage device After inserting the USB card re
174. d and before the installation begins If you have configured the network in the kickstart file the network is enabled before this section is processed To include a pre installation script type it in the text area To specify a scripting language to use to execute the script select the Use an interpreter option and enter the interpreter in the text box beside it For example usr bin python2 2 can be specified for a Python script This option corresponds to using pre interpreter usr bin python2 2 in your kickstart file CO eaution Do not include the spre command It will be added for you Chapter 10 Kickstart Configurator 77 10 11 Post Installation Script File Help Basic Configuration Post Installation Script Installation Method Warming An error in this script might cause your kickstart installation to fail Do not include the post command at the beginning Boot Loader Options Partition Information Run outside of the chroot environment Network Configuration Use an interpreter Authentication Firewall Configuration Type your post script below X Configuration Package Selection Pre installation Script Post Installation Script Figure 10 16 Post Installation Script You can also add commands to execute on the system after the installation is completed If the net work is properly configured in the kickstart file the network is enabled and the script can include commands to acces
175. d clicking Edit For example you can configure whether the device is started at boot time and any routes to use while the device is activated When the device is added it is not activated immediately as seen by its Inactive status To activate the device select it from the device list and click the Activate button If the system is configured to activate the device when the computer starts the default this step does not have to be performed again For more information on CIPE and setting up CIPE refer to the Red Hat Enterprise Linux Security Guide 19 8 Establishing a Wireless Connection Wireless Ethernet devices are becoming increasingly popular The configuration is similar to the Eth ernet configuration except that it allows you to configure settings such as the SSID and key for the wireless device To add a wireless Ethernet connection follow these steps 1 Click the Devices tab 2 Click the New button on the toolbar 3 Select Wireless connection from the Device Type list and click Forward 4 If you have already added the wireless network interface card to the hardware list select it from the Wireless card list Otherwise select Other Wireless Card to add the hardware device 134 Chapter 19 Network Configuration Note The installation program usually detects supported wireless Ethernet devices and prompts you to configure them If you configured them during the installation they are displayed in the hardw
176. d only It also mounts its individual snapshot directory as read write Then it mounts all the files and directories in the files and files custom files using the mount o bind over the read only 100 Chapter 15 Diskless Environments diskless directory to allow applications to write to the root directory of the diskless environment if they need to lll Package Management All software on a Red Hat Enterprise Linux system is divided into RPM packages which can be installed upgraded or removed This part describes how to manage the RPM packages on a Red Hat Enterprise Linux system using graphical and command line tools Table of Contents 16 Package Management With RPM ssssssssssssssssssssecsssessssssssessssseseesesesssssesessesessseeseseseseseenes 103 17 Package Management Tol ssssssssssssssssssscssssssssssessesessessssecsesesssssssessssessesessesessesseserseses 113 18 Red Hat Network cscsssssssssssssssssesssssssessesssesssssssssseseseesesssssssessesesesessenscssesessssssasesssesseessosers 117 redhat Chapter 16 Package Management with RPM The RPM Package Manager RPM is an open packaging system available for anyone to use which runs on Red Hat Enterprise Linux as well as other Linux and UNIX systems Red Hat Inc encourages other vendors to use RPM for their own products RPM is distributable under the terms of the GPL For the end user RPM makes system updates easy Installing uninstalling an
177. d rm For example to remove the partition with minor number 3 rm 3 The changes start taking place as soon as you press Enter so review the command before committing to it After removing the partition use the print command to confirm that it is removed from the partition table You should also view the output of cat proc partitions to make sure the kernel knows the partition is removed The last step is to remove it from the etc fstab file Find the line that declares the removed partition and remove it from the file 5 4 Resizing a Partition A waming Do not attempt to resize a partition on a device that is in use Before resizing a partition boot into rescue mode or unmount any partitions on the device and turn off any swap space on the device Start parted where dev hda is the device on which to resize the partition parted dev hda View the current partition table to determine the minor number of the partition to resize as well as the start and end points for the partition print waming The used space of the partition to resize must not be larger than the new size To resize the partition use the resize command followed by the minor number for the partition the starting place in megabytes and the end place in megabytes For example resize 3 1024 2048 20 Chapter 5 Managing Disk Storage After resizing the partition use the print command to confirm that the partition has been resized c
178. d services Non xinetd services can not be started stopped or restarted using this program e chkconfig a command line utility that allows you to turn services on and off for the different runlevels Changes do not take effect immediately for non xinetd services Non xinetd services can not be started stopped or restarted using this utility You may find that these tools are easier to use than the alternatives editing the numerous symbolic links located in the directories below etc rc d by hand or editing the xinetd configuration files in etc xinetd d Another way to manage access to system services is by using iptables to configure an IP firewall If you are a new Linux user please realize that iptables may not be the best solution for you Setting up iptables can be complicated and is best tackled by experienced Linux system administrators On the other hand the benefit of using iptables is flexibility For example if you need a customized solution which provides certain hosts access to certain services iptables can provide it for you Refer to the Red Hat Enterprise Linux Reference Guide and the Red Hat Enterprise Linux Security Guide for more information about iptables Alternatively if you are looking for a utility to set general access rules for your home machine and or if you are new to Linux try the Security Level Configuration Tool redhat config securitylevel which allows you to select the security level for your sy
179. d upgrading RPM pack ages can be accomplished with short commands RPM maintains a database of installed packages and their files so you can invoke powerful queries and verifications on your system If you prefer a graph ical interface you can use Package Management Tool to perform many RPM commands Refer to Chapter 17 Package Management Tool for details During upgrades RPM handles configuration files carefully so that you never lose your customiza tions something that you can not accomplish with regular tar gz files For the developer RPM allows you to take software source code and package it into source and binary packages for end users This process is quite simple and is driven from a single file and optional patches that you create This clear delineation between pristine sources and your patches along with build instructions eases the maintenance of the package as new versions of the software are released Note Because RPM makes changes to your system you must be root to install remove or upgrade an RPM package 16 1 RPM Design Goals To understand how to use RPM it can be helpful to understand RPM s design goals Upgradability Using RPM you can upgrade individual components of your system without completely rein stalling When you get a new release of an operating system based on RPM such as Red Hat Enterprise Linux you do not need to reinstall on your machine as you do with operating systems based on oth
180. ddress of the main contact for the master zone File Name File name of DNS database file in the var named directory A WN Primary Nameserver SOA State of authority SOA record This specifies the nameserver that is the best resource of information for this domain 6 Serial Number The serial number of the DNS database file This number must be incre mented each time the file is changed so that the slave nameservers for the zone retrieve the latest data The Domain Name Service Configuration Tool increments this number each time the configuration changes It can also be incremented manually by clicking the Set button next to the Serial Number value 7 Time Settings The Refresh Retry Expire and Minimum TTL Time to Live values that are stored in the DNS database file o0 Nameservers Add edit and delete name servers for the reverse master zone At least one nameserver is required 9 Reverse Address Table List of IP addresses within the reverse master zone and their host names For example for the reverse master zone 192 168 10 192 168 10 1 can be added in the Reverse Address Table with the hostname one example com The hostname must end with a period to specify that it is a full hostname 216 Reverse Master Zone IP Address Reverse IP Address Contact 192 168 10 10 168 192 in addr arpa root localhost Chapter 28 BIND Configuration File Name 10 168 192 in addr
181. dit Copy Del Deactivate Devices Hardware DNS Hosts You may configure network devices associated with Go physical hardware here Multiple logical devices can be associated with a single piece of hardware Prot Status Device Nickname Type N Active f ethO eth0 1 Ethernet amp Active etho etho Ethernet Active Profile Common Figure 19 21 Network Device Alias Example Select the alias and click the Activate button to activate the alias If you have configured multiple profiles select which profiles in which to include it To verify that the alias has been activated use the command sbin ifconfig The output should show the device and the device alias with different IP address etho Link encap Ethernet HWaddr 00 A0 CC 60 B7 G4 inet addr 192 168 100 5 Bcast 192 168 100 255 Mask 255 255 255 0 UP BROADCAST RUNNING MULTICAST MTU 1500 Metric 1 RX packets 161930 errors 1 dropped 0 overruns 0 frame 0 TX packets 244570 errors 0 dropped 0 overruns 0 carrier 0 collisions 475 txqueuelen 100 RX bytes 55075551 52 5 Mb TX bytes 178108895 169 8 Mb Interrupt 10 Base address 0x9000 eth0 1 Link encap Ethernet HWaddr 00 A0 CC 60 B7 G4 inet addr 192 168 100 42 Bcast 192 168 100 255 Mask 255 255 255 0 UP BROADCAST RUNNING MULTICAST MTU 1500 Metric 1 Interrupt 10 Base address 0x9000 lo Link encap Local Loopback inet addr 127 0 0 1 Mask 255 0 0 0 Chapter 19 N
182. e redhat config network cmd profile lt profilename gt activate 19 13 Device Aliases Device aliases are virtual devices associated with the same physical hardware but they can be acti vated at the same time to have different IP addresses They are commonly represented as the device name followed by a colon and a number for example eth0 1 They are useful if you want to have multiple IP address for a system but the system only has one network card 140 Chapter 19 Network Configuration After configuring the Ethernet device such as et h0 to use a static IP address DHCP does not work with aliases go to the Devices tab and click New Select the Ethernet card to configure with an alias set the static IP address for the alias and click Apply to create it Since a device already exists for the Ethernet card the one just created is the alias such as eth0 1 waming If you are configuring an Ethernet device to have an alias neither the device nor the alias can be configured to use DHCP You must configure the IP addresses manually Figure 19 21 shows an example of one alias for the etno device Notice the eth0 1 device the first alias for eth0 The second alias for ethO would have the device name eth0 2 and so on To modify the settings for the device alias such as whether to activate it at boot time and the alias number select it from the list and click the Edit button Eile Profile Help Brag x New E
183. e Grow to maximum of MB 1 Fill all unused space on disk Use recommended swap size Force to be a primary partition asprimary 7 Make partition on specific drive ondisk Drive sda for example hda or sdc xisting partition onpart ition for example hdal or sdc3 X Cancel Pox Figure 10 6 Creating a Software RAID Partition Repeat these steps to create as many partitions as needed for your RAID setup All of your partitions do not have to be RAID partitions After creating all the partitions needed to form a RAID device follow these steps 1 Click the RAID button 2 Select Create a RAID device 3 Select a mount point file system type RAID device name RAID level RAID members number of spares for the software RAID device and whether to format the RAID device Mount Point home File System Type ext3 z RAID Device mdo RAID Level 0 T Z raid 01 dl Raid Members Number of spares 1 7 Format RAID device X Cancel Pox Figure 10 7 Creating a Software RAID Device 4 Click OK to add the device to the list 70 10 5 Network Configuration Chapter 10 Kickstart Configurator File Help Basic Configuration Network Configuration Installation Method Device Network Type Add Network Device Boot Loader Options
184. e dev oprofile directory if it does not already exist Refer to Section 43 6 Understanding dev profile for details about this directory Note Even if OProfile is configured not to profile the kernel the SMP kernel still must be running so that the oprofile module can be loaded from it Setting whether samples should be collected within the kernel only changes what data is collected not how or where the collected data is stored To generate different sample files for the kernel and application libraries refer to Section 43 2 3 Separating Kernel and User space Profiles 43 2 2 Setting Events to Monitor Most processors contain counters which are used by OProfile to monitor specific events As shown in Table 43 2 the number of counters available depends on the processor Number of Counters Pentium 4 hyper threaded i386 p4 ht Athlon i386 athlon AMD64 x86 64 hammer l l IBM eServer zSeries 1 Table 43 2 OProfile Processors and Counters ia6ftanium Use Table 43 2 to verify that the correct processor type was detected and to determine the number of events that can be monitored simultaneously timer is used as the processor type if the processor does not have supported performance monitoring hardware If timer is used events can not be set for any processor because the hardware does not have support for hardware performance counters Instead the timer interrupt is used for profiling If timer is not used as the p
185. e Authentication section select whether to use shadow passwords and MDS encryption for user passwords These options are highly recommended and chosen by default The Authentication Configuration options allow you to configure the following methods of authen tication NIS LDAP Kerberos 5 Hesiod SMB Name Switch Cache These methods are not enabled by default To enable one or more of these methods click the appropri ate tab click the checkbox next to Enable and enter the appropriate information for the authentication method Refer to Chapter 29 Authentication Configuration for more information about the options 10 7 Firewall Configuration The Firewall Configuration window is similar to the screen in the installation program and the Se curity Level Configuration Tool 72 Chapter 10 Kickstart Configurator File Help Basic Configuration Firewall Configuration Installation Method Security level Enable firewall Boot Loader Options Partition Information Ung IES L etho Network Configuration O ethi Authentication X Configuration Trusted services WWW HTTP Package Selection CF Pre Installation Script O ssH Post installation Script LI Telnet Mail SMTP Other ports 1029 tcp Figure 10 10 Firewall Configuration If Disable firewall is selected the system allows complete access to any active services and ports No connections to the system are refused or den
186. e Linux and then performed an upgrade you can use the HTTP Configuration Tool to migrate the configuration file to the new format for version 2 0 Start the HTTP Configura tion Tool make any changes to the configuration and save it The configuration file saved will be compatible with version 2 0 The HTTP Configuration Tool allows you to configure the etc httpd conf httpd conf con figuration file for the Apache HTTP Server It does not use the old srm conf or access conf configuration files leave them empty Through the graphical interface you can configure directives such as virtual hosts logging attributes and maximum number of connections Only modules provided with Red Hat Enterprise Linux can be configured with HTTP Configuration Tool If additional modules are installed they can not be configured using this tool The httpd and redhat config httpd RPM packages need to be installed to use the HTTP Con figuration Tool It also requires the X Window System and root access To start the application go to the Main Menu Button gt System Settings gt Server Settings gt HTTP or type the command redhat config httpdat a shell prompt for example in an XTerm or GNOME Terminal QO eaution Do not edit the etc httpd conf httpd conf configuration file by hand if you wish to use this tool The HTTP Configuration Tool generates this file after you save your changes and exit the program If you want to add additional modules or config
187. e NFS server configured in Section 15 3 Configuring the NFS Server as well as the directory exported as the diskless environment Click Forward Chapter 15 Diskless Environments 99 4 The kernel versions installed in the diskless environment are listed Select the kernel version to boot on the diskless system 5 Click Apply to finish the configuration After clicking Apply the diskless kernel and image file are created based on the kernel selected They are copied to the PXE boot directory t ftpboot linux install lt os identifier gt The directory snapshot is created in the same directory as the root directory for example diskless i386 RHEL3 AS snapshot with a file called files in it This file contains a list of files and directories that must be read write for each diskless system Do not modify this file If additional entries need to be added to the list create a files custom file in the same directory as the files file and add each additional file or directory on a separate line 15 5 Adding Hosts Each diskless client must have its own snapshot directory on the NFS server that is used as its read write file system The Network Booting Tool can be used to create these snapshot directories After completing the steps in Section 15 4 Finish Configuring the Diskless Environment a window appears to allow hosts to be added for the diskless environment Click the New button In the dialog shown in Figure 15 1 provide the follo
188. e a separate boot partition which is not a part of a volume group Once all the physical volumes are created follow these steps 1 Click the LVM button to collect the physical volumes into volume groups A volume group is basically a collection of physical volumes You can have multiple logical volume groups but a physical volume can only be in one volume group Note There is overhead disk space reserved in the logical volume group The summation of the physical volumes may not equal the size of the volume group however the size of the logical volumes shown is correct Make LVM Volume Group Volume Group Name Volumeod Physical Extent 4MB r K hda2 19384 00 MB Z hdb2 17468 00 MB Physical Volumes to Use Used Space 30000 00 MB 81 4 Free Space 6852 00 MB 18 6 Total Space 36852 00 MB Logical Volumes Logical Volume Name Mount Point Size MB LogVol00 home 30000 Add Edit Delete X Cancel Oa Figure 13 2 Creating an LVM Device 2 Change the Volume Group Name if desired Chapter 13 LVM Configuration 89 3 All logical volumes inside the volume group must be allocated in physical extent units By default the physical extent is set to 4 MB thus logical volume sizes must be divisible by 4 MBs If you enter a size that is not a unit of 4 MBs the installation program automatically selects the closest size in units of 4 MBs It is not recommended that you change this
189. e emulated by selecting Emulate 3 Buttons If this option is selected simultaneously clicking the left and right mouse buttons will be recognized as a middle mouse button click 64 Chapter 10 Kickstart Configurator From the Time Zone menu choose the time zone to use for the system To configure the system to use UTC select Use UTC clock Enter the desired root password for the system in the Root Password text entry box Type the same password in the Confirm Password text box The second field is to make sure you do not mistype the password and then realize you do not know what it is after you have completed the installation To save the password as an encrypted password in the file select Encrypt root password If the encryption option is selected when the file is saved the plain text password that you typed will be encrypted and written to the kickstart file Do not type an already encrypted password and select to encrypt it Because a kickstart file is a plain text file that can be easily read it is recommended that an encrypted password be used To install languages in addition to the one selected from the Default Language pulldown menu check them in the Language Support list The language selected from the Default Language pulldown menu is used by default after installation however the default can be changed with the Language Configuration Tool redhat config language after installation Choosing Reboot system after installation wi
190. e has not been completed when the installation executes the spost section You can access the network but you can not resolve IP addresses Thus if you are using DHCP you must specify IP addresses in the spost section Note The post install script is run in a chroot environment therefore performing tasks such as copying scripts or RPMs from the installation media will not work nochroot Allows you to specify commands that you would like to run outside of the chroot environment The following example copies the file etc resolv conf to the file system that was just in stalled Spost nochroot cp etc resolv conf mnt sysimage etc resolv conf 58 Chapter 9 Kickstart Installations interpreter usr bin python Allows you to specify a different scripting language such as Python Replace usxr bin python with the scripting language of your choice 9 7 1 Examples Turn services on and off sbin chkconfig level 345 telnet off sbin chkconfig level 345 finger off sbin chkconfig level 345 lpd off sbin chkconfig level 345 httpd on Run a script named runme from an NFS share mkdir mnt temp mount 10 10 0 2 usr new machines mnt temp open s w mnt temp runme umount mnt temp Add a user to the system usr sbin useradd bob usr bin chfn f Bob Smith bob usr sbin usermod p kjdf 04930FTH bob 9 8 Making the Kickstart File Available A kickstart file must be placed in one of the
191. e main disadvantage is that there is a very small performance hit due to the overhead associated with the TCP protocol 23 2 4 Preserving ACLs The Red Hat Enterprise Linux 3 kernel provides ACL support for the ext3 file system and ext3 file systems mounted with the NFS or Samba protocols Thus if an ext3 file system has ACLs enabled for it and is NFS exported if the NFS client can read ACLs they are used by the NFS client as well For more information about mounting NFS file systems with ACLs refer to Chapter 8 Access Control Lists 23 3 Exporting NFS File Systems Sharing files from an NFS server is known as exporting the directories The NFS Server Configura tion Tool can be used to configure a system as an NFS server To use the NFS Server Configuration Tool you must be running the X Window System have root privileges and have the redhat config nfs RPM package installed To start the application select Main Menu Button on the Panel gt System Settings gt Server Settings gt NFS or type the command redhat config nfs 166 Chapter 23 Network File System NFS me Add F Help Directory Hosts Permissions Figure 23 1 NFS Server Configuration Tool To add an NFS share click the Add button The dialog box shown in Figure 23 2 will appear The Basic tab requires the following information Directory Specify the directory to share such as tmp Host s Specify the host
192. e same directory structure 60 Chapter 9 Kickstart Installations If you are performing a CD based installation insert the Red Hat Enterprise Linux CD ROM 1 into the computer before starting the kickstart installation If you are performing a hard drive installation make sure the ISO images of the binary Red Hat Enterprise Linux CD ROMs are on a hard drive in the computer If you are performing a network based NFS FTP or HTTP installation you must make the installa tion tree available over the network Refer to the Preparing for a Network Installation section of the Red Hat Enterprise Linux Installation Guide for details 9 10 Starting a Kickstart Installation To begin a kickstart installation you must boot the system from a Red Hat Enterprise Linux boot diskette Red Hat Enterprise Linux boot CD ROM or the Red Hat Enterprise Linux CD ROM 1 and enter a special boot command at the boot prompt The installation program looks for a kickstart file if the ks command line argument is passed to the kernel Boot Diskette If the kickstart file is located on a boot diskette as described in Section 9 8 1 Creating a Kickstart Boot Diskette boot the system with the diskette in the drive and enter the following command at the boot prompt linux ks floppy CD ROM 1 and Diskette The linux ks floppy command also works if the ks cfg file is located on a vfat or ext2 file system on a diskette and you boot from the Red Hat Enterprise Linu
193. e selected mail daemon is enabled to start at boot time and the unselected mail daemon is disabled so that is does not start at boot time The selected mail daemon is started and the other mail daemon is stopped thus making the changes take place immediately For more information about email protocols and MTAs refer to the Red Hat Enterprise Linux Refer ence Guide 290 Chapter 41 Mail Transport Agent MTA Configuration VI System Monitoring System administrators also monitor system performance Red Hat Enterprise Linux contains tools to assist administrators with these tasks Table of Contents 42 Gathering System Information ccsssssccsesssssssssssssssssscssessssssesesesssesessesessssssssesesesesesserers 293 43 O i EI D ROEE AE TT E E T EET EN 299 redhat Chapter 42 Gathering System Information Before you learn how to configure your system you should learn how to gather essential system information For example you should know how to find the amount of free memory the amount of available hard drive space how your hard drive is partitioned and what processes are running This chapter discusses how to retrieve this type of information from your Red Hat Enterprise Linux system using simple commands and a few simple programs 42 1 System Processes The ps ax command displays a list of current system processes including processes owned by other users To display the owner of the processes along with the p
194. e user may be any valid user on the system g lt gid gt lt perms gt Sets the access ACL for a group The group name or GID may be specified The group may be any valid group on the system m lt perms gt Sets the effective rights mask The mask is the union of all permissions of the owning group and all of the user and group entries o lt perms gt Sets the access ACL for users other than the ones in the group for the file Whitespace is ignored Permissions lt jperms gt must be a combination of the characters r w and x for read write and execute If a file or directory already has an ACL and the set facl command is used the additional rules are added to the existing ACL or the existing rule is modified For example to give read and write permissions to user tfox setfacl m u tfox rw project somefile To remove all the permissions for a user group or others use the x option and do not specify any permissions setfacl x lt rules gt lt files gt For example to remove all permissions from the user with UID 500 setfacl x u 500 project somefile 8 3 Setting Default ACLs To set a default ACL add d before the rule and specify a directory instead of a file name For example to set the default ACL for the share directory to read and execute for users not in the user group an access ACL for an individual file can override it setfacl m d o rx share Chapter 8 Access Control Lists 33 8 4 Retrie
195. e would love to hear from you Please submit a report in Bugzilla http bugzilla redhat com bugzilla against the component rhel sag Be sure to mention the manual s identifier rhel sag EN 3 Print RHI 2003 07 25T17 10 By mentioning this manual s identifier we will know exactly which version of the guide you have If you have a suggestion for improving the documentation try to be as specific as possible If you have found an error please include the section number and some of the surrounding text so we can find it easily 4 Sign Up for Support If you have an edition of Red Hat Enterprise Linux 3 please remember to sign up for the benefits you are entitled to as a Red Hat customer You will be entitled to any or all of the following benefits depending upon the product you purchased Red Hat support Get help with your installation questions from Red Hat Inc s support team vi Introduction Red Hat Network Easily update your packages and receive security notices that are customized for your system Go to http rhn redhat com for more details Under the Brim The Red Hat E Newsletter Every month get the latest news and product infor mation directly from Red Hat To sign up go to http www redhat com apps activate You will find your Product ID on a black red and white card in your Red Hat Enterprise Linux box To read more about technical support for Red Hat Enterprise Linux refer to the
196. earn more about it for users who want to compile an experimental feature into the kernel and so on To upgrade the kernel using the kernel packages distributed by Red Hat Inc refer to Chapter 39 Upgrading the Kernel A waming Building a custom kernel is not supported by the Installation Support Team For more information on upgrading the kernel using the RPM packages distributed by Red Hat Inc refer to Chapter 39 Upgrading the Kernel A 1 Preparing to Build Before building a custom kernel it is extremely important to make sure that a working emergency boot diskette exists in case a mistake is made To make a boot diskette that will boot using the currently running kernel execute the following command sbin mkbootdisk uname r After making the diskette test it to make sure that it boots the system To recompile the kernel the kerne1l source package must be installed Issue the command rpm q kernel source to determine if it is installed If it is not installed install it from the Red Hat Enterprise Linux CD ROMs or Red Hat Network For more information on installing RPM packages refer to Part III Package Management A 2 Building the Kernel To build a custom kernel perform all these steps as root f Note This example uses 2 4 21 1 1931 2 399 ent as the kernel version the kernel version might differ To determine the kernel version type the command uname r and replace 2 4 21 1 1931 2 399 ent with the
197. econds Filesystem Block grace period Inode grace period dev hda3 7days 7days Change the block grace period or inode grace period save the changes to the file and exit the text editor 6 2 Managing Disk Quotas If quotas are implemented they need some maintenance mostly in the form of watching to see if the quotas are exceeded and making sure the quotas are accurate Of course if users repeatedly exceeds their quotas or consistently reaches their soft limits a system administrator has a few choices to make depending on what type of users they are and how much disk space impacts their work The administrator can either help the user determine how to use less disk space or increase the user s disk quota if needed 6 2 1 Reporting on Disk Quotas Creating a disk usage report entails running the repquota utility For example the command repquota home produces this output Report for user quotas on device dev hda3 Block grace time 7days Inode grace time 7days Block limits File limits User used soft hard grace used soft hard grace root me 36 0 0 4 0 0 tfox bs 540 0 0 125 0 0 testuser 440400 500000 550000 37418 0 0 To view the disk usage report for all quota enabled file systems use the command repquota a While the report is easy to read a few points should be explained The displayed after each user is a quick way to determine whether the block or inode limits have been exceeded If either soft limit is e
198. ectly related to the security maintained on the host machine For example if an unscrupulous individual compromises the regular UNIX security on the host machine that person could obtain your private key the contents of your server key file The key could be used to serve Web pages that appear to be from your secure server If UNIX security practices are rigorously maintained on the host computer all operating system patches and updates are installed as soon as they are available no unnecessary or risky services are operating and so on secure server s passphrase may seem unnecessary However since your secure server should not need to be re booted very often the extra security provided by entering a passphrase is a worthwhile effort in most cases The server key file should be owned by the root user on your system and should not be accessible to any other user Make a backup copy of this file and keep the backup copy in a safe secure place You need the backup copy because if you ever lose the server key file after using it to create your Chapter 27 Apache HTTP Secure Server Configuration 209 certificate request your certificate no longer works and the CA is not able to help you Your only option is to request and pay for a new certificate If you are going to purchase a certificate from a CA continue to Section 27 7 Generating a Certificate Request to Send to a CA If you are generating your own self signed certificate contin
199. ectory so that one client can not affect the others The following steps are necessary to configure Red Hat Enterprise Linux to run on a diskless client Install Red Hat Enterprise Linux on a system so that the files can be copied to the NFS server Refer to the Red Hat Enterprise Linux Installation Guide for details Any software to be used on the clients must be installed on this system and the busybox anaconda package must be installed 2 Create a directory on the NFS server to contain the diskless environment such as diskless i386 RHEL3 AS For example mkdir p diskless i386 RHEL3 AS This directory is referred to as the diskless directory 3 Create a subdirectory of this directory named root mkdir p diskless i386 RHEL3 AS root 4 Copy Red Hat Enterprise Linux from the client system to the server using rsync For example rsync a e ssh installed system example com diskless i386 RHEL3 AS root The length of this operation depends on the network connection speed as well as the size of the file system on the installed system It may take a while 5 Start the t ftp server as discussed in Section 15 1 Start the t ftp Server 6 Configure the DHCP server as discussed in Section 15 2 Configuring the DHCP Server 7 Finish creating the diskless environment as discussed in Section 15 4 Finish Configuring the Diskless Environment 8 Configure the diskless clients as discussed in Section 15 5 Adding Hosts 9 Conf
200. ecurity to encrypt passwords sent to the LDAP server LDAP Search Base DN Retrieve user information by its Distinguished Name DN LDAP Server Specify the IP address of the LDAP server The openldap clients package must be installed for this option to work Refer to the Red Hat Enterprise Linux Reference Guide for more information about LDAP Enable Kerberos Support Select this option to enable Kerberos authentication Click the Con figure Kerberos button to configure Realm Configure the realm for the Kerberos server The realm is the network that uses Ker beros composed of one or more KDCs and a potentially large number of clients KDC Define the Key Distribution Center KDC which is the server that issues Kerberos tickets Admin Servers Specify the administration server s running kadmind 222 Chapter 29 Authentication Configuration The krb5 1libs and krb5 workstation packages must be installed for this option to work Refer to the Red Hat Enterprise Linux Reference Guide for more information on Kerberos Enable SMB Support This option configures PAM to use an SMB server to authenticate users Click the Configure SMB button to specify Workgroup Specify the SMB workgroup to use Domain Controllers Specify the SMB domain controllers to use 29 3 Command Line Version The Authentication Configuration Tool can also be run as a command line tool with no interface The c
201. ed by our readers Significant changes to this manual include ii Introduction Chapter 7 User Defined Device Names This new chapter explains how to use devlabel Chapter 8 Access Control Lists This new chapter explains the how to use access control lists for files and directories Chapter 9 Kickstart Installations This chapter has been updated to include new kickstart directives Chapter 10 Kickstart Configurator This chapter has been updated to include the new options in Kickstart Configurator Chapter 14 PXE Network Installations This new chapter explains how to perform a PXE installation Chapter 15 Diskless Environments This new chapter explains how to create a diskless environment Chapter 24 Samba This chapter has been updated for Samba 3 0 and now explains how to mount Samba shares Chapter 32 Keyboard Configuration This new chapter explains the Keyboard Configuration Tool Chapter 33 Mouse Configuration This new chapter explains the Mouse Configuration Tool Chapter 34 X Window System Configuration This new chapter explains the X Configuration Tool Chapter 38 Log Files This chapter has been updated to explain the new features of Log Viewer Chapter 39 Upgrading the Kernel This chapter has been updated to explain the new kernel packages as well as how to upgrade the kernel on architectures other than x86 Chapter 43 OProfile This new chapter explains the how to use the OProfile system profiler
202. ed Hat Inc Release ane Build Date Fri 07 Feb 2003 04 07 32 PM EST Install date not installed Build Host porky devel redhat com Group System Environment Base Source RPM crontabs 1 10 5 src rpm Size 1004 License Public Domain Signature DSA SHA1 Tue 11 Feb 2003 01 46 46 PM EST Key ID d372689897da07a Packager Red Hat Inc lt http bugzilla redhat com bugzilla gt Summary Root crontab files used to schedule the execution of programs Description The crontabs package contains root crontab files Crontab is the program used to install uninstall or list the tables used to drive the cron daemon The cron daemon checks the crontab files to see when particular commands are scheduled to be executed If commands are scheduled then it executes them Perhaps you now want to see what files the crontabs RPM installs You would enter the following rpm qlp crontabs 1 10 5 noarch rpm The output is similar to the following Name crontabs Relocations not relocateable Version rare PEEL Vendor Red Hat Inc Release 9 Build Date Fri 07 Feb 2003 04 07 32 PM EST Install date not installed Build Host porky devel redhat com Group System Environment Base Source RPM crontabs 1 10 5 src rpm Size 1004 License Public Domain Signature DSA SHA1 Tue 11 Feb 2003 01 46 46 PM EST Key ID d372689897da07a Packager Red Hat Inc lt http bugzilla redhat com bugzilla gt Summary Root crontab files used to sch
203. edule the execution of programs Description The crontabs package contains root crontab files Crontab is the 112 Chapter 16 Package Management with RPM program used to install uninstall or list the tables used to drive the cron daemon The cron daemon checks the crontab files to see when particular commands are scheduled to be executed If commands are scheduled then it executes them These are just a few examples As you use it you will find many more uses for RPM 16 5 Additional Resources RPM is an extremely complex utility with many options and methods for querying installing upgrad ing and removing packages Refer to the following resources to learn more about RPM 16 5 1 Installed Documentation rpm help This command displays a quick reference of RPM parameters man rpm The RPM man page gives more detail about RPM parameters than the rpm help command 16 5 2 Useful Websites http www rpm org The RPM website http www redhat com mailman listinfo rpm list The RPM mailing list is archived here To subscribe send mail to lt rpm list request redhat com gt with the word subscribe in the subject line 16 5 3 Related Books Red Hat RPM Guide by Eric Foster Johnson Wiley John amp Sons Incorporated This book is a comprehensive guide to RPM from installing package to building RPMs redhat Chapter 17 Package Management Tool During installation a default set
204. efault variable to the value of the Label for the image section that contains the new kernel Begin testing the new kernel by rebooting the computer and watching the messages to ensure that the hardware is detected properly 39 6 3 IBM S 390 and IBM eServer zSeries Systems The IBM S 390 and IBM eServer zSeries systems use z IPL as the boot loader which uses etc zipl conf as the configuration file Confirm that the file contains a section with the same version as the kernel package just installed defaultboot default old target boot linux image boot vmlinuz 2 4 21 1 1931 2 399 ent ramdisk boot initrd 2 4 21 1 1931 2 399 ent img parameters root LABEL old image boot vmlinuz 2 4 20 2 30 ent ramdisk boot initrd 2 4 20 2 30 ent img parameters root LABEL Notice that the default is not set to the new kernel To configure z IPL to boot the new kernel by default change the value of the default variable to the name of the section that contains the new kernel The first line of each section contains the name in brackets After modifying the configuration file run the following command as root to enable the changes sbin zipl Begin testing the new kernel by rebooting the computer and watching the messages to ensure that the hardware is detected properly Chapter 39 Upgrading the Kernel 283 39 6 4 IBM eServer iSeries Systems The boot vmlinitrd lt kernel version gt file is installed when you upgrade the kerne
205. ent utility can be used to save your passphrase so that you do not have to enter it each time you initiate an ssh or scp connection If you are using GNOME the openssh askpass gnome utility can be used to prompt you for your passphrase when you log in to GNOME and save it until you log out of GNOME You will not have to enter your password or passphrase for any ssh or scp connection made during that GNOME session If you are not using GNOME refer to Section 22 3 4 5 Configuring ssh agent To save your passphrase during your GNOME session follow the following steps 1 You will need to have the package openssh askpass gnome installed you can use the com mand rpm q openssh askpass gnome to determine if it is installed or not If it is not in stalled install it from your Red Hat Enterprise Linux CD ROM set from a Red Hat FTP mirror site or using Red Hat Network 2 Select Main Menu Button on the Panel gt Preferences gt More Preferences gt Sessions and click on the Startup Programs tab Click Add and enter usr bin ssh add in the Startup Command text area Set it a priority to a number higher than any existing commands to ensure that it is executed last A good priority number for ssh add is 70 or higher The higher the priority number the lower the priority If you have other programs listed this one should have the lowest priority Click Close to exit the program 3 Log out and then log back into GNOME in other words
206. ents of the kickstart file after you have finished choosing your kickstart options select File gt Preview from the pull down menu You have choosen the following configuration Click Save File to save the kickstart file Generated by Kickstart Configurator Ka System language lang en_US Language modules to install langsupport default en_US System keyboard keyboard us System mouse mouse generic3ps 2 Sytem timezone timezone America New_York Root password rootpw iscrypted 1 dMdNAAZn oSP_JSBQTX8gXv Reboot after installation reboot Install Red Hat Linux instead of upgrade install Use CDROM installation media cdrom X gji gt Cancel save to File Figure 10 17 Preview To save the kickstart file click the Save to File button in the preview window To save the file without previewing it select File gt Save File or press Ctrl S A dialog box appears Select where to save the file After saving the file refer to Section 9 10 Starting a Kickstart Installation for information on how to start the kickstart installation redhat Chapter 11 Basic System Recovery When things go wrong there are ways to fix problems However these methods require that you understand the system well This chapter describes how to boot into rescue mode single user mode and emergency mode where you can use your own knowledge to
207. er Exiting the application does not stop OProfile from sampling 43 9 Additional Resources This chapter only highlights OProfile and how to configure and use it To learn more refer to the following resources 43 9 1 Installed Docs e usr share doc oprofile 0 5 4 oprofile html OProfile Manual oprofile man page Discusses opcont rol oprofpp op_to_source op_time op_merge and op_help 43 9 2 Useful Websites http oprofile sourceforge net contains the latest documentation mailing lists IRC channels and more Vil Appendixes This part contains instructions for building a custom kernel from the source files provided by Red Hat Inc Table of Contents A Building a Custom Kernel csscsssssssssssssssesessssssssesesssssssessesssssesseserssesessesesssessssesesesesessavene 315 redhat Appendix A Building a Custom Kernel Many people new to Linux often ask Why should I build my own kernel Given the advances that have been made in the use of kernel modules the most accurate response to that question is Unless you already know why you need to build your own kernel you probably do not need to The kernel provided with Red Hat Enterprise Linux and via the Red Hat Enterprise Linux Errata system provides support for most modern hardware and kernel features For most users it does not need to be recompiled This appendix is provided as a guide for users who want to recompile their kernel to l
208. er SOA must be specified and at least one nameserver record must be speci fied by clicking the Add button in the Records section After configuring the Forward Master Zone click OK to return to the main window as shown in Figure 28 1 From the pulldown menu click Save to write the etc named conf configuration file write all the individual zone files in the var named directory and have the daemon reload the configuration files The configuration creates an entry similar to the following in etc named conf Chapter 28 BIND Configuration 215 zone forward example com type master file forward example com zone i It also creates the file var named forward example com zone with the following information STTL 86400 IN SOA ns example com root localhost 2 serial 28800 refresh 7200 retry 604800 expire 86400 ttl IN NS 192 168 1 1 28 2 Adding a Reverse Master Zone To add a reverse master zone click the New button and select Reverse Master Zone Enter the first three octets of the IP address range to be configure For example to configure the IP address range 192 168 10 0 255 255 255 0 enter 192 168 10 in the IP Address first 3 Octets text area A new window appears as shown in Figure 28 3 with the following options IP Address The first three octets entered in the previous window Reverse IP Address Non editable Pre populated based on the IP Address entered Contact Email a
209. er packaging systems RPM allows intelligent fully automated in place upgrades of your system Configuration files in packages are preserved across upgrades so you won t lose your customizations There are no special upgrade files needed to upgrade a package because the same RPM file is used to install and upgrade the package on your system Powerful Querying RPM is designed to provide powerful querying options You can do searches through your entire database for packages or just for certain files You can also easily find out what package a file belongs to and from where the package came The files an RPM package contains are in a com pressed archive with a custom binary header containing useful information about the package and its contents allowing you to query individual packages quickly and easily System Verification Another powerful feature is the ability to verify packages If you are worried that you deleted an important file for some package verify the package You are notified of any anomalies At that 104 Chapter 16 Package Management with RPM point you can reinstall the package if necessary Any configuration files that you modified are preserved during reinstallation Pristine Sources A crucial design goal was to allow the use of pristine software sources as distributed by the original authors of the software With RPM you have the pristine sources along with any patches that were used plus complete build inst
210. ermissions but misc export speedy example com rw sync would allow users from speedy example com to mount misc export with read write privileges Refer to Section 23 3 2 Hostname Formats for an explanation of possible hostname formats Refer to the Red Hat Enterprise Linux Reference Guide for a list of options that can be specified 168 Chapter 23 Network File System NFS O caution Be careful with spaces in the etc exports file If there are no spaces between the hostname and the options in parentheses the options apply only to the hostname If there is a space between the hostname and the options the options apply to the rest of the world For example examine the following lines misc export speedy example com rw sync misc export speedy example com rw sync The first line grants users from speedy example com read write access and denies all other users The second line grants users from speedy example com read only access the default and allows the rest of the world read write access Each time you change etc exports you must inform the NFS daemon of the change or reload the configuration file with the following command sbin service nfs reload 23 3 2 Hostname Formats The host s can be in the following forms Single machine A fully qualified domain name that can be resolved by the server hostname that can be resolved by the server or an IP address e Series of machines specified with w
211. erred to each time an address is resolved A waming Do not remove the localhost entry Even if the system does not have a network connection or have a network connection running constantly some programs need to connect to the system via the localhost loopback interface File Profile Help S Be New Edit Copy Delete Devices Hardware IPsec DNS Hosts You may specify static computer hostname to IP address mappings here If DNS is in use these settings will take precedence over any information it may provide IP Name aliases Figure 19 17 Hosts Configuration Chapter 19 Network Configuration 137 Om To change lookup order edit the etc host conf file The line order hosts bind specifies that the etc hosts takes precedence over the name servers Changing the line to order bind hosts configures the system to resolve hostnames and IP addresses using the name servers first If the IP address cannot be resolved through the name servers the system then looks for the IP address in the etc hosts file 19 11 Activating Devices Network devices can be configured to be active or inactive at boot time For example a network device for a modem connection is usually not configured to start at boot time whereas an Ethernet connection is usually configured to activate at boot time If your network device is configured not to start at boot time you can use the
212. ers dashes and underscores _ Optionally enter a short description for the printer which can contain spaces Select Networked Windows SMB from the Select a queue type menu and click Forward If the printer is attached to a Microsoft Windows system choose this queue type 254 Chapter 36 Printer Configuration Select a queue type Networked Windows SMB T Heip 3 Cancel lt d Back D Forward Figure 36 7 Adding a SMB Printer As shown in Figure 36 7 SMB shares are automatically detected and listed Click the arrow beside each share name to expand the list From the expanded list select a printer If the printer you are looking for does not appear in the list click the Specify button on the right Text fields for the following options appear Workgroup The name of the Samba workgroup for the shared printer Server The name of the server sharing the printer Share The name of the shared printer on which you want to print This name must be the same name defined as the Samba printer on the remote Windows machine User name The name of the user you must log in as to access the printer This user must exist on the Windows system and the user must have permission to access the printer The default user name is typically guest for Windows servers or nobody for Samba servers Password The password if requ
213. ers are used to look up other hosts on the network Hostname Hocalhost localdomain Primary DNS 172 16 52 28 Secondary DNS 172 16 52 27 Tertiary DNS DNS Search Path devel redhat com Figure 19 16 DNS Configuration 136 Chapter 19 Network Configuration gt Note The name servers section does not configure the system to be a name server Instead it configures the name servers to use when resolving IP address to hostnames and vice versa 19 10 Managing Hosts The Hosts tab allows you to add edit or remove hosts from the etc hosts file This file contains IP addresses and their corresponding hostnames When your system tries to resolve a hostname to an IP address or determine the hostname for an IP address it refers to the etc hosts file before using the name servers if you are using the default Red Hat Enterprise Linux configuration If the IP address is listed in the etc hosts file the name servers are not used If your network contains computers whose IP addresses are not listed in DNS it is recommended that you add them to the etc hosts file To add an entry to the etc hosts file go to the Hosts tab click the New button on the toolbar provide the requested information and click OK Select File gt Save or press Ctrl S to save the changes to the etc hosts file The network or network services do not need to be restarted since the current version of the file is ref
214. erver To enable this feature select Enable Network Time Protocol This enables the Server pulldown menu You can choose one of the predefined servers or type a server name in the pulldown menu Your system does not start synchronizing with the NTP server until you click OK After you click OK the configuration is be saved and the NTP daemon is started or restarted if it is already running 232 Chapter 31 Date and Time Configuration Clicking the OK button applies any changes made to the date and time the NTP daemon settings and the time zone settings It also exits the program 31 2 Time Zone Configuration To configure the system time zone click the Time Zone tab The time zone can be changed by either using the interactive map or by choosing the desired time zone from the list below the map To use the map click on the city that represents the desired time zone A red X appears and the time zone selection changes in the list below the map Click OK to apply the changes and exit the program Date amp Time Time Zone Please select the nearest city in your timezone America Montserrat America Nassau America Nipigon Eastem Time Ontario amp Quebec places that AmericayNome Alaska Time west Alaska G gt O system clock uses UTC Bue cancer 2 ox Figure 31 2 Timezone Properties If your system clock is set to u
215. es SHELL bin bash PATH sbin bin usr sbin usr bin MAILTO root HOME run parts 01 root run parts etc cron hourly 02 4 root run parts etc cron daily 22 4 0 root run parts etc cron weekly Ba wE 42 4 root run parts etc cron monthly The first four lines are variables used to configure the environment in which the cron tasks are run The value of the SHELL variable tells the system which shell environment to use in this example the bash shell and the PATH variable defines the path used to execute commands The output of the cron tasks are emailed to the username defined with the MAILTO variable If the MAILTO variable is defined as an empty string MAILTO email is not sent The HOME variable can be used to set the home directory to use when executing commands or scripts Each line in the etc crontab file represents a task and has the format minute hour day month dayofweek command minute any integer from 0 to 59 hour any integer from 0 to 23 day any integer from 1 to 31 must be a valid day if a month is specified 268 Chapter 37 Automated Tasks month any integer from 1 to 12 or the short name of the month such as jan or feb dayofweek any integer from 0 to 7 where 0 or 7 represents Sunday or the short name of the week such as sun or mon command the command to execute the command can either be a command such as 1s proc gt gt tmp proc or the co
216. es fix security and other bugs W Bua Fix RHBA 2002 273 Updated mm packages available F Enhancement RHSA 2002 254 Updated Webalizer packages fix vulnerability RHSA 2002 220 Updated KDE packages fix security issues RHSA 2002 229 Updated wget packages fix directory traversal bug RHSA 2002 196 Updated xinetd packages fix denial of service vulnerability RHSA 2002 222 Updated apache httpd and mod_ssl packages available RHSA 2002 263 New samba packages available to fix potential security vulnerability RHSA 2002 262 New kemel fixes local denial of service issue PHB Updated version of GCC 2 96 RH now available RHSA 2002 197 Updated glibc packages fix vulnerabilties in resolver RHS 2002 242 Updated kerberos packages available RHSA 2002 213 New PHP packages fix vulnerability in mail function RHSA 2002 223 Updated ypserv packages fixes memory leak RHS 205 New kemel fixes local security issues SEee000 282 RAER RHSA 2002 192 Updated Mozilla packages fix security vulnerabilities No systems selected Manage Clear 1 17 of 17 PENER Update 2 20021217 1 20021217 0 20024211 O 200212 04 1 20021204 2 20021204 1 20024202 1 2002 11 25 1 2002 11 21 3 2002 11 16 0 2002 11 11 O 2002 11 06 O 2002 11 06 O 2002 11 04 O 2002 10 24 0 20021015 O 2002 10 08 1 170417 em 7 Figure 18 2 Relevant Errata Automatic email notifications receive an email noti
217. es security using a combination of the Secure Sockets Layer SSL protocol and in most cases a digital certificate from a Certificate Authority CA SSL handles the encrypted communications and the mutual authentication between browsers and your secure server The CA approved digital certificate provides authentication for your secure server the CA puts its reputation behind its certification of your organization s identity When your browser is communicating using SSL encryption the https prefix is used at the beginning of the Uniform Resource Locator URL in the navigation bar Encryption depends upon the use of keys think of them as secret encoder decoder rings in data for mat In conventional or symmetric cryptography both ends of the transaction have the same key which they use to decode each other s transmissions In public or asymmetric cryptography two keys co exist a public key and a private key A person or an organization keeps their private key a secret and publishes their public key Data encoded with the public key can only be decoded with the private key data encoded with the private key can only be decoded with the public key To set up your secure server use public cryptography to create a public and private key pair In most cases you send your certificate request including your public key proof of your company s identity and payment to a CA The CA verifies the certificate request and your identity and then
218. esessesesssssssessssessesessssesserseseres 15 Diskless Environments redhat Chapter 9 Kickstart Installations 9 1 What are Kickstart Installations Many system administrators would prefer to use an automated installation method to install Red Hat Enterprise Linux on their machines To answer this need Red Hat created the kickstart installation method Using kickstart a system administrator can create a single file containing the answers to all the questions that would normally be asked during a typical installation Kickstart files can be kept on single server system and read by individual computers during the in stallation This installation method can support the use of a single kickstart file to install Red Hat Enterprise Linux on multiple machines making it ideal for network and system administrators Kickstart provides a way for users to automate a Red Hat Enterprise Linux installation 9 2 How Do You Perform a Kickstart Installation Kickstart installations can be performed using a local CD ROM a local hard drive or via NFS FTP or HTTP To use kickstart you must 1 Create a kickstart file 2 Create a boot diskette with the kickstart file or make the kickstart file available on the network 3 Make the installation tree available 4 Start the kickstart installation This chapter explains these steps in detail 9 3 Creating the Kickstart File The kickstart file is a simple text file contain
219. etwork Configuration 141 UP LOOPBACK RUNNING MTU 16436 Metric 1 RX packets 5998 errors 0 dropped 0 overruns 0 frame 0 TX packets 5998 errors 0 dropped 0 overruns 0 carrier 0 collisions 0 txqueuelen 0 RX bytes 1627579 1 5 Mb TX bytes 1627579 1 5 Mb 19 14 Establishing an IPsec Connection IPsec stands for Internet Protocol Security It is a Virtual Private Network solution in which an en crypted connection is established between two systems host to host or two networks network to network OG Go to http www ipsec howto org for more information about IPsec 19 14 1 Host to Host Connection A host to host IPsec connection is an encrypted connection between two systems both running IPsec with the same authentication key With the IPsec connection active any network traffic between the two hosts is encrypted To configure a host to host IPsec connection use the following steps for each host 1 Start the Network Administration Tool 2 From the IPsec tab select New 3 Click Forward to start configuring a host to host IPsec connection 4 Provide a one word nickname such as ipsec0O for the connection and select whether the con nection should be automatically activated when the computer starts Click Forward 5 Select Host to Host encryption as the connection type Click Forward 6 Select the type of encryption to use manual or automatic If manual is selected an encryption key must be provided later in the
220. ext and other middle mouse button functions If the mouse only has two buttons select Emulate 3 buttons to use a two button mouse as a three button mouse When this option enabled clicking the two mouse buttons simultaneously emulates a middle mouse button click If a serial port mouse is selected click the Serial devices button to configure the correct serial device number such as dev ttySso0 for the mouse Click OK to save the new mouse type The selection is written to the file etc sysconfig mouse and the console mouse service gpm is restarted The changes are also written to the X Window System configuration file etc X11 XF86Config however the mouse type change is not automatically applied to the current X session To enable the new mouse type log out of the graphical desktop and log back in o To reset the order of the mouse buttons for a left handed user go to the Main Menu Button on the Panel gt Preferences gt Mouse and select Left handed mouse for the mouse orientation redhat Chapter 34 X Window System Configuration During installation the system s monitor video card and display settings are configured To change any of these settings for the system use the X Configuration Tool To start the X Configuration Tool select Main Menu Button on the Panel gt System Settings gt Display or type the command redhat config xfree86 at a shell prompt for example in an XTerm or GNOME terminal If the
221. f httpd conf bak noran After saving your settings you must restart the httpd daemon with the command service httpd restart You must be logged in as root to execute this command 26 7 Additional Resources To learn more about the Apache HTTP Server refer to the following resources 26 7 1 Installed Documentation usr share docs httpd lt version gt migration html The Apache Migration HOWTO document contains a list of changes from version 1 3 to version 2 0 as well as information about how to migration the configuration file manually 202 Chapter 26 Apache HTTP Server Configuration 26 7 2 Useful Websites http www apache org The Apache Software Foundation http httpd apache org docs 2 0 The Apache Software Foundation s documentation on Apache HTTP Server version 2 0 including the Apache HTTP Server Version 2 0 User s Guide http www redhat com support resources web_ftp apache html Red Hat Support maintains a list of useful Apache HTTP Server links http www redhat com support docs faqs RH apache FAQ book 1 html The Apache Centralized Knowledgebase compiled by Red Hat 26 7 3 Related Books Apache The Definitive Guide by Ben Laurie and Peter Laurie O Reilly amp Associates Inc Red Hat Enterprise Linux Reference Guide Red Hat Inc This companion manual includes instructions for migrating from Apache HTTP Server version 1 3 to Apache HTTP Server version 2 0
222. f the following HH MM format For example 04 00 specifies 4 00AM If the time is already past it is executed at the specified time the next day midnight Specifies 12 00AM noon Specifies 12 00PM teatime Specifies 4 00PM month name day year format For example January 15 2002 specifies the 15th day of January in the year 2002 The year is optional e MMDDYY MM DD YY or MM DD YY formats For example 011502 for the 15th day of January in the year 2002 now time time is in minutes hours days or weeks For example now 5 days specifies that the command should be executed at the same time five days from now The time must be specified first followed by the optional date For more information about the time format read the usr share doc at lt version gt timespec text file After typing the at command with the time argument the at gt prompt is displayed Type the command to execute press Enter and type Ctrl D More than one command can be specified by typing each command followed by the Enter key After typing all the commands press Enter to go to a blank line and type Ctrl D Alternatively a shell script can be entered at the prompt pressing Enter after each line in the script and typing Ctrl D on a blank line to exit If a script is entered the shell used is the shell set in the user s SHELL environment the user s login shell or bin sh whichever is found first
223. f you want the Windows Username option to work Refer to Section 24 2 1 2 Managing Samba Users for details Encrypt Passwords This option must be enabled if the clients are connecting from a Windows 98 Windows NT 4 0 with Service Pack 3 or other more recent versions of Microsoft Windows The passwords are transfered between the server and the client in an encrypted format instead of in as a plain text word that can be intercepted This corresponds to the encrypted passwords option Refer to Section 24 2 3 Encrypted Passwords for more information about encrypted Samba passwords Guest Account When users or guest users log into a Samba server they must be mapped to a valid user on the server Select one of the existing usernames on the system to be the guest Samba account When guests logs in to the Samba server they have the same privileges as this user This corresponds to the guest account option After clicking OK the changes are written to the configuration file and the daemon is restart thus the changes take effect immediately 24 2 1 2 Managing Samba Users The Samba Server Configuration Tool requires that an existing user account be active on the system acting as the Samba server before a Samba user can be added The Samba user is associated with the existing user account tfox Add User bfox Edit User Delete User Figure 24 4 Managing Samba Users 174 Chapter 24 Samba
224. fer the contents of the directory downloads to an existing directory called uploads on the remote machine penguin example net type the following at a shell prompt scp downloads username penguin example net uploads 22 3 3 Using the sftp Command The sftp utility can be used to open a secure interactive FTP session It is similar to ftp except that it uses a secure encrypted connection The general syntax is sftp username hostname com Once authenticated you can use a set of commands similar to those used by FTP Refer to the sftp man page for a list of these commands To read the man page execute the command man sftp ata shell prompt The sftp utility is only available in OpenSSH version 2 5 0p1 and higher 22 3 4 Generating Key Pairs If you do not want to enter your password every time you use ssh scp or sftp to connect to a remote machine you can generate an authorization key pair Keys must be generated for each user To generate keys for a user use the following steps as the user who wants to connect to remote machines If you complete the steps as root only root will be able to use the keys Starting with OpenSSH version 3 0 ssh authorized_keys2 ssh known_hosts2 and etc ssh_known_hosts2 are obsolete SSH Protocol 1 and 2 share the ssh authorized_keys ssh known_hosts and etc ssh ssh_known_hosts files Red Hat Enterprise Linux 3 uses SSH Protocol 2 and RSA keys by default If you reinstall and
225. fication when an Errata Alert is issued for your system e Scheduled Errata Updates schedule delivery of Errata Updates e Package installation Schedule package installation on one or more systems with the click of a button Red Hat Update Agent use the Red Hat Update Agent to download the latest software pack ages for your system with optional package installation Red Hat Network website manage multiple systems downloaded individual packages and schedule actions such as Errata Updates through a secure Web browser connection from any com puter O eaution You must activate your Red Hat Enterprise Linux product before registered your system with Red Hat Network to make sure your system is entitled to the correct services To activate your product go to http www redhat com apps activate After activating your product registered it with Red Hat Network to receive Errata Updates The registration process gathers information about the system that is required to notify you of updates For example a list of packages installed on the system is compiled so you are only notified about updates that are relevant to your system Chapter 18 Red Hat Network 119 The first time the system is booted the Setup Agent prompts you to register If you did not register then select Main Menu Button gt System Tools gt Red Hat Network on your desktop to start the registration process Alternately execute the command
226. following locations Ona boot diskette Ona boot CD ROM Ona network Normally a kickstart file is copied to the boot diskette or made available on the network The network based approach is most commonly used as most kickstart installations tend to be performed on net worked computers Let us take a more in depth look at where the kickstart file may be placed 9 8 1 Creating a Kickstart Boot Diskette To perform a diskette based kickstart installation the kickstart file must be named ks cfg and must be located in the boot diskette s top level directory Refer to the section Making an Installation Boot Diskette in the Red Hat Enterprise Linux Installation Guide for instruction on creating a boot diskette Because the boot diskettes are in MS DOS format it is easy to copy the kickstart file under Linux using the mcopy command mcopy ks cfg a Alternatively you can use Windows to copy the file You can also mount the MS DOS boot diskette in Red Hat Enterprise Linux with the file system type vfat and use the cp command to copy the file on the diskette Chapter 9 Kickstart Installations 59 9 8 2 Creating a Kickstart Boot CD ROM To perform a CD ROM based kickstart installation the kickstart file must be named ks cfg and must be located in the boot CD ROM s top level directory Since a CD ROM is read only the file must be added to the directory used to create the image that is written to the CD ROM Refer to the Making
227. following options Name Domain name that was just entered in the previous window File Name File name of the DNS database file relative to var named It is preset to the domain name with zone appended to it Contact Email address of the main contact for the master zone Primary Nameserver SOA State of authority SOA record This specifies the nameserver that is the best resource of information for this domain Serial Number The serial number of the DNS database file This number must be incremented each time the file is changed so that the slave nameservers for the zone retrieve the latest data The Domain Name Service Configuration Tool increments this number each time the configuration changes It can also be incremented manually by clicking the Set button next to the Serial Number value Time Settings The Refresh Retry Expire and Minimum TTL Time to Live values that are stored in the DNS database file All values are in seconds Records Add edit and delete record resources of type Host Alias and Name server Master Zone Name forward example com File Name forward example com zone Contact root localhost Primary Nameserver SOA Serial Number 1 Set Time Settings Records forward example com Add f Edit Delete 3 Cancel 2 OK Figure 28 2 Adding a Forward Master Zone A Primary Nameserv
228. for the HTTP directory Hard Drive Choose this option to install or upgrade from a hard drive Hard drive installations require the use of ISO or CD ROM images Be sure to verify that the ISO images are intact before you start the installation To verify them use an md5sum program as well as the linux mediacheck boot option as discussed in the Red Hat Enterprise Linux Installation Guide Enter the hard drive partition that contains the ISO images for example dev hda1 in the Hard Drive Partition text box Enter the directory that contains the ISO images in the Hard Drive Directory text box 66 Chapter 10 Kickstart Configurator 10 3 Boot Loader Options File Help Basic Configuration Boot Loader Options required Installation Method Install new boot loader Boot Loader Options Do not install a boot loader Partition Information ON ERS SSSI RSENS Network Configuration Use GRUB for the boot loader Authentication O Use LILO for the boot loader Firewall Configuration GRUB Options Configuration Use GRUB password Package Selection Pre Installation Script Password Confirm Password Post Installation Script Encrypt GRUB password Install boot loader on Master Boot Record MBR Install boot loader on first sector of the boot partition Kemel parameters Figure 10 3 Boot Loader Options You have the option of installing GRUB or LILO as the boot loader If you do not w
229. fore the changes made by the request are written to the disk This option corresponds to sync If this is not selected the async option is used Force sync of write operations immediately Do not delay writing to disk This option cor responds to no_wdelay Chapter 23 Network File System NFS 167 The User Access tab allows the following options to be configured Treat remote root user as local root By default the user and group IDs of the root user are both 0 Root squashing maps the user ID 0 and the group ID 0 to the user and group IDs of anonymous so that root on the client does not have root privileges on the NFS server If this option is selected root is not mapped to anonymous and root on a client has root privileges to exported directories Selecting this option can greatly decrease the security of the system Do not select it unless it is absolutely necessary This option corresponds to no_root_squash Treat all client users as anonymous users If this option is selected all user and group IDs are mapped to the anonymous user This option corresponds to all_squash Specify local user ID for anonymous users If Treat all client users as anonymous users is selected this option lets you specify a user ID for the anonymous user This option corresponds to anonuid Specify local group ID for anonymous users If Treat all client users as anonymous users is selected this option lets you specify a group ID fo
230. from within the X Window System Then select the Process Listing tab The GNOME System Monitor allows you to search for process in the list of running process as well as view all processes your processes or active processes To learn more about a process select it and click the More Info button Details about the process will be displayed at the bottom of the window To stop a process select it and click End Process This function is useful for processes that have stopped responding to user input To sort by the information in a specific column click on the name of the column The column that the information is sorted by appears in a darker gray color By default the GNOME System Monitor does not display threads To change this preferences select Edit gt Preferences click the Process Listing tab and select Show Threads The preferences also allows you to configure the update interval what type of information to display about each process by default and the colors of the system monitor graphs Chapter 42 Gathering System Information File Edit View Help Search View My Processes M4 Process Name User Memory CPU Jio 2 bonobo activation server tfox 23MB 0 27059 fam tfox 1 5MB 0 27049 gconfd 2 tfox 43MB 0 27032 amp gnome panel tfox 12 9MB 0 27051 v gnome session tfox 85MB 0 26936 ssh agent tfox 1012K 0 27021 gnome settings daemon tfox 7 1MB 0 27039 v E gnome terminal tfox 83MB 0 27858
231. ge and Section 39 6 Verifying the Boot Loader except do not change the kernel to boot by default because Red Hat Network automatically changes the default kernel to the latest version To install the kernel manually continue to Section 39 4 Performing the Upgrade 39 4 Performing the Upgrade After retrieving all the necessary packages it is time to upgrade the existing kernel At a shell prompt as root change to the directory that contains the kernel RPM packages and follow these steps noran It is strongly recommended that the old kernel is kept in case there are problems with the new kernel Use the i argument with the rpm command to keep the old kernel If the u option is used to upgrade the kernel package it will overwrite the currently installed kernel the kernel version may vary rpm ivh kernel 2 4 21 1 1931 2 399 ent lt arch gt rpm If the system is a multi processor system install the kerne1 smp packages as well the kernel version may vary rpm ivh kernel smp 2 4 21 1 1931 2 399 ent lt arch gt rpm 280 Chapter 39 Upgrading the Kernel If the system is i686 based and contains more than 4 gigabytes of RAM install the kerne1 hugemem package built for the i686 architecture as well the kernel version might vary rpm ivh kernel hugemem 2 4 21 1 1931 2 399 ent i686 rpm If the kernel source or kernel utils packages are to be upgraded the older versions are prob ably not needed Use the following commands
232. ge file transfers Because the dedicated parity disk represents an inherent bottleneck level 4 is seldom used without accompanying technologies such as write back caching Although RAID level 4 is an option in some RAID partitioning schemes it is not an option allowed in Red Hat Enterprise Linux RAID installations The storage capacity of Hardware RAID level 4 is equal to the capacity of member disks minus the capacity of one member disk The storage capacity of Software RAID level 4 is equal to the capacity of the member partitions minus the size of one of the partitions if they are of equal size Level 5 This is the most common type of RAID By distributing parity across some or all of an array s member disk drives RAID level 5 eliminates the write bottleneck inherent in level 4 The only performance bottleneck is the parity calculation process With modern CPUs and Software RAID that usually is not a very big problem As with level 4 the result is asymmetrical perfor mance with reads substantially outperforming writes Level 5 is often used with write back caching to reduce the asymmetry The storage capacity of Hardware RAID level 5 is equal to the capacity of member disks minus the capacity of one member disk The storage capacity of Software RAID level 5 is equal to the capacity of the member partitions minus the size of one of the partitions if they are of equal size Linear RAID Linear RAID is a simple grouping of drives
233. gt Preferences from the pulldown menu and click on the Alerts tab Click the Add button to add an alert word To delete an alert word select the word from the list and click Delete The alert icon is displayed to the left of the lines that contains any of the alert words Log Files Alerts Warnings Alerts Show alert icon for the following key words fail Add denied rejected Delete oops segfault segmentation x Close Figure 38 4 Alerts To add warning words select Edit gt Preferences from the pull down menu and click on the Warn ings tab Click the Add button to add a warning word To delete a warning word select the word from the list and click Delete 276 Chapter 38 Log Files The warning icon gt is displayed to the left of the lines that contains any of the warning words Figure 38 5 Warning Log Files Alerts Warnings Warnings A Show warning icon for the following key words wam Ada Delete x Close amp redhat Chapter 39 Upgrading the Kernel The Red Hat Enterprise Linux kernel is custom built by the Red Hat kernel team to ensure its integrity and compatibility with supported hardware Before Red Hat releases a kernel it must first pass a rigorous set of quality assurance tests Red Hat Enterprise Linux kernels are packaged in RPM format so that they
234. gure 19 5 ISDN Device 19 4 Establishing a Modem Connection A modem can be used to configure an Internet connection over an active phone line An Internet Service Provider ISP account also called a dial up account is required To add a modem connection follow these steps 1 Click the Devices tab 2 Click the New button on the toolbar 3 Select Modem connection from the Device Type list and click Forward 127 4 If there is a modem already configured in the hardware list on the Hardware tab the Network Administration Tool assumes you want to use it to establish a modem connection If there are no modems already configured it tries to detect any modems in the system This probe might take a while If a modem is not found a message is displayed to warn you that the settings shown are not values found from the probe 5 After probing the window in Figure 19 6 appears Select Modem Modem Properties Modem Device dev ttySO Baud Rate 57600 X Elow Control Hardware CRTSCTS Y Modem Volume Off z Use touch tone dialing 28 Cancel lt Back D Forward Figure 19 6 Modem Settings 128 Chapter 19 Network Configuration 6 Configure the modem device baud rate flow control and modem volume If you do not know these values accept the defaults if the modem was probed successfully If you do not have touch tone dialing
235. h GNOME If you are not running the X Window System skip to Section 22 3 4 5 Configuring ssh agent Chapter 22 OpenSSH 161 22 3 4 3 Generating an RSA Key Pair for Version 1 3 and 1 5 Use the following steps to generate an RSA key pair which is used by version of the SSH Protocol If you are only connecting between systems that use DSA you do not need an RSA version 1 3 or RSA version 1 5 key pair 1 To generate an RSA for version 1 3 and 1 5 protocol key pair type the following command at a shell prompt ssh keygen t rsal Accept the default file location ssh identity Enter a passphrase different from your account password Confirm the passphrase by entering it again The public key is written to ssh identity pub The private key is written to ssh identity Do not give anyone the private key 2 Change the permissions of your ssh directory and your key with the commands chmod 755 sshand chmod 644 ssh identity pub 3 Copy the contents of ssh identity pub to the file ssh authorized_keys on the machine to which you wish to connect If the file ssh authorized_keys does not exist you can copy the file ssh identity pub to the file ssh authorized_keys on the remote machine 4 If you are running GNOME skip to Section 22 3 4 4 Configuring ssh agent with GNOME If you are not running GNOME skip to Section 22 3 4 5 Configuring ssh agent 22 3 4 4 Configuring ssh agent with GNOME The ssh ag
236. hanged but the runlevel is not restarted thus the changes do not take place immediately For example assume you are configuring runlevel 3 If you change the value for the httpd service from checked to unchecked and then select Save Changes the runlevel 3 configuration changes so that httpd is not started at boot time However runlevel 3 is not reinitialized so httpd is still running Select one of following options at this point 1 Stop the httpd service Stop the service by selecting it from the list and clicking the Stop button A message appears stating that the service was stopped successfully 2 Reinitialize the runlevel Reinitialize the runlevel by going to a shell prompt and typing the command telinit 3 where 3 is the runlevel number This option is recommended if you change the Start at Boot value of multiple services and want to activate the changes immedi ately 3 Do nothing else You do not have to stop the httpd service You can wait until the system is rebooted for the service to stop The next time the system is booted the runlevel is initialized without the httpd service running To add a service to a runlevel select the runlevel from the Edit Runlevel pulldown menu and then select Actions gt Add Service To delete a service from a runlevel select the runlevel from the Edit Runlevel pulldown menu select the service to be deleted from the list on the left and select Actions gt Delete Service 21
237. harename in the Location bar for Nautilus using the following syntax replace lt servername gt and lt sharename gt with the appropriate values smb lt servername gt lt sharename gt 24 3 1 Command Line To query the network for Samba servers use the f indsmb command For each server found it displays its IP address NetBIOS name workgroup name operating system and SMB server version To connect to a Samba share from a shell prompt type the following command smbclient lt hostname gt lt sharename gt U lt username gt Replace lt hostname gt with the hostname or IP address of the Samba server you want to connect to lt sharename gt with the name of the shared directory you want to browse and lt username gt with the Samba username for the system Enter the correct password or press Enter if no password is required for the user If you see the smb gt prompt you have successfully logged in Once you are logged in type help for a list of commands If you wish to browse the contents of your home directory replace sharename with your username If the uU switch is not used the username of the current user is passed to the Samba server To exit smbclient type exit at the smb gt prompt 24 3 2 Mounting the Share Sometimes it is useful to mount a Samba share to a directory so the files in the directory can be treated as if they are part of the local file system To mount a Samba share to a directory
238. hat can be defined in the configuration file To start the OpenSSH service use the command sbin service sshd start To stop the OpenSSH server use the command sbin service sshd stop If you want the daemon to start automatically at boot time refer to Chapter 21 Controlling Access to Services for information on how to manage services If you reinstall and clients connected to the system before the reinstall with any of the OpenSSH tools after the reinstall the client users will see the following message CC AAEEEAAEEEAAEEEEAEEEEAAEEEEEEAEEEEEEEEEEEEEAEEEEEREEEEEEE WARNING REMOTE HOST IDENTIFICATION HAS CHANGED CC AEEEEAAEEEEREEEEAEEEEAAEEEEEEAEEEEEEEEEEEEEAEEEEEREEEEEEE IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY Someone could be eavesdropping on you right now man in the middle attack It is also possible that the RSA host key has just been changed The reinstalled system creates a new set of identification keys for the system hence the warning about the RSA host key changing If you want to keep the host keys generated for the system backup the etc ssh ssh_host key files and restore them after the reinstall This process retains the system s identity and when clients try to connect to the system after the reinstall they will not receive the warning message 158 Chapter 22 OpenSSH 22 3 Configuring an OpenSSH Client To connect to an OpenSSH server from a client machine you must have the openssh clients
239. he Browse button to locate the file location using a file selection dialog Click OK to return to the preferences and click Close to return to the main window Figure 38 2 Log Files Alerts Wamings Log Files X Configure the path and filename for each log file displayed Log File Location i Add Boot Log var log boot log Edit Cron Li og varflog cron Delete Kemel Startup Log var log dmesg Mail Log var log maillog ma MySQL Server Log var log mysqld log News Log var log spooler RPM Packages varflog rpmpkgs X Refresh Rate Refresh log file every 30 seconds xXx Close Log File Locations Chapter 38 Log Files 275 38 3 Adding a Log File To add a log file to the list select Edit gt Preferences and click the Add button in the Log Files tab x Specify a new log file location Name Custom Log Description A description of my custom log Location jyar log custom log Cancel OK Figure 38 3 Adding a Log File Provide a name description and the location of the log file to add After clicking OK the file is immediately added to the viewing area if the file exists 38 4 Examining Log Files Log Viewer can be configured to display an alert icon beside lines that contain key alert words and a warning icon beside lines that contain key warning words To add alerts words select Edit
240. he console using Ctrl Alt Del When that key combination is used the shutdown a in etc inittab checks to see if any of the users in etc shutdown allow or root are logged in on a virtual console If one of them is the shutdown of the system continues if not an error message is written to the system console instead For more information on shut down allow see the shutdown man page 228 Chapter 30 Console Access 30 2 Disabling Console Program Access To disable access by users to console programs run the following command as root rm f etc security console apps In environments where the console is otherwise secured BIOS and boot loader passwords are set Ctrl Alt Delete is disabled the power and reset switches are disabled and so forth you may not want to allow any user at the console to run poweroff halt and reboot which are accessible from the console by default To remove these abilities run the following commands as root rm f etc security console apps poweroff rm f etc security console apps halt rm f etc security console apps reboot 30 3 Disabling All Console Access The PAM pam_console so module manages console file permissions and authentication Refer to the Red Hat Enterprise Linux Reference Guide for more information on configuring PAM To disable all console access including program and file access comment out all lines that refer to pam_console so inthe etc pam d directory As ro
241. he devlabe1 device name such as dev usbcard and create the mount point such as mnt usbcard After modifying the line it should look similar to the following dev usbcard mnt usbcard auto noauto owner 0 0 Because of automount when devlabel is restarted the storage media in the USB card reader device is mounted in mnt usbcard when the USB device is plugged into the computer The trick is that when the USB card reader is plugged into the computer the card must already be in the reader If not devlabel can not find the storage device and thus it can not automatically mount it If the USB card reader is already plugged in without a card when the card is inserted run the com mand devlabel restart as root to mount the media card 7 2 How It Works The command devlabel restart is called from the etc rc sysinit script when the system is booted as well as by the appropriate scripts in the etc hotplug directory The restart option to devlabel reads the list of devices in the configuration file etc sysconfig devlabel and follows the symbolic links to determine if the device still exists in its former location such as dev hdb1 If the symbolic link is invalid an attempt is made to find the new location of the disk based on the disk s UUID If a disk with the same UUID is found the symbolic link is updated to point to the new location of the drive the configuration file is updated with the new location and a message similar
242. he first time the system is rebooted It is disabled by default but the setting can be changed to enabled or enabled in reconfiguration mode Reconfigu ration mode enables the language mouse keyboard root password security level time zone and networking configuration options in addition to the default ones 10 8 2 Video Card Probe for video card is selected by default Accept this default to have the installation program probe for the video card during installation Probing works for most modern video cards If this option is selected and the installation program cannot successfully probe the video card the installation program will stop at the video card configuration screen To continue the installation process select your video card from the list and click Next Alternatively you can select the video card from the list on the Video Card tab as shown in Figure 10 12 Specify the amount of video RAM the selected video card has from the Video Card RAM pulldown menu These values are used by the installation program to configure the X Window System 74 Chapter 10 Kickstart Configurator Eile Help Basic Configuration X Configuration Installation Method 7 Configure the X Window System Boot Loader Options General Video Card Monitor Partition Information Probe for vid o card Network Configuration ei ee nape ee tee Authentication Magic Pro MP 740DVD Firewall Configuration Matrox Co
243. he system Password Info This tab shows the date that the user s password last changed To force the user to change passwords after a certain number of days select Enable password expiration The number of days before the user s password expires the number of days before the user is warned to change passwords and days before the account becomes inactive can also be changed Groups Select the groups that you want the user to be a member of and the user s primary group 35 3 Adding a New Group To add a new user group click the Add Group button A window similar to Figure 35 4 appears Type the name of the new group to create To specify a group ID for the new group select Specify group ID manually and select the GID Red Hat Enterprise Linux reserves group IDs lower than 500 for system groups Click OK to create the group The new group appears in the group list Group Name mygroup Specify group ID manually 3 Cancel OK Figure 35 4 New Group To add users to the group refer to Section 35 4 Modifying Group Properties 242 Chapter 35 User and Group Configuration 35 4 Modifying Group Properties To view the properties of an existing group select the group from the group list and click Properties from the button menu or choose File gt Properties from the pulldown menu A window similar to Figure 35 5 appears Group Data Group Users Group Name
244. hive if they do not exist in the archive or if the files are newer than the files of the same name in the archive This option only work if the archive is a file or an unblocked tape that may backspace Extracts the files from the archive If used with U and a file in the archive is older than the corresponding file on the file system the file is not extracted Displays the most important options Displays the least important options Do not strip leading slashes from file names when extracting the files from an archive By default they are striped when files are extracted When creating or extracting archive or restore any ACLs associated with the files and directories Table 8 1 Command Line Options for star 8 6 Compatibility with Older Systems If an ACL has been set on any file on a given file system that file system has the ext_att r attribute This attribute can be seen using the following command tune2fs 1 lt filesystem device gt A file system that has acquired the ext_attr attribute can be mounted with older kernels but those kernels do not enforce any ACLs which have been set Versions of the e2 fsck utility included in version 1 22 and higher of the e2 sprogs package includ ing the versions in Red Hat Enterprise Linux 2 1 and 3 can check a file system with the ext_attr attribute Older versions refuse to check it 8 7 Additional Resources Refer to the follow resources for more information 8 7 1
245. ied Selecting Enable firewall configures the system to reject incoming connections that are not in re sponse to outbound requests such as DNS replies or DHCP requests If access to services running on this machine is needed you can choose to allow specific services through the firewall Only devices configured in the Network Configuration section are listed as available Trusted de vices Connections from any devices selected in the list are accepted by the system For example if eth1 only receives connections from internal system you might want to allow connections from it If a service is selected in the Trusted services list connections for the service are accepted and processed by the system In the Other ports text field list any additional ports that should be opened for remote access Use the following format port protocol For example to allow IMAP access through the firewall specify imap tcp Specify numeric ports can also be specified to allow UDP packets on port 1234 through the firewall enter 1234 udp To specify multiple ports separate them with commas 10 8 X Configuration If you are installing the X Window System you can configure it during the kickstart installation by checking the Configure the X Window System option on the X Configuration window as shown in Figure 10 11 If this option is not chosen the X configuration options will be disabled and the skipx option will be written to the kickstart file 10
246. ify the user is located on the local system and other times the system defers the authentication to a user database on a remote system The Authentication Configuration Tool provides a graphical interface for configuring NIS LDAP and Hesiod to retrieve user information as well as for configuring LDAP Kerberos and SMB as authentication protocols Note If you configured a medium or high security level during installation or with the Security Level Con figuration Tool network authentication methods including NIS and LDAP are not allowed through the firewall This chapter does not explain each of the different authentication types in detail Instead it explains how to use the Authentication Configuration Tool to configure them To start the graphical version of the Authentication Configuration Tool from the desktop select Main Menu Button on the Panel gt System Settings gt Authentication or type the command authconfig gtk at a shell prompt for example in an XTerm or a GNOME terminal To start the text based version type the command authconfig at a shell prompt noran After exiting the authentication program the changes made take effect immediately 29 1 User Information The User Information tab has several options To enable an option click the empty checkbox beside it To disable an option click the checkbox beside it to clear the checkbox Click OK to exit the program and apply the changes 220 Chapter 29 A
247. iguration Package Management This guide assumes you have a basic understanding of your Red Hat Enterprise Linux system If you need help installing Red Hat Enterprise Linux refer to the Red Hat Enterprise Linux Installation Guide For more general information about system administration refer to the Red Hat Enterprise Linux Introduction to System Administration If you need more advanced documentation such as an overview of file systems refer to the Red Hat Enterprise Linux Reference Guide If you need security information refer to the Red Hat Enterprise Linux Security Guide HTML PDF and RPM versions of the manuals are available on the Red Hat Enterprise Linux Docu mentation CD and online at http www redhat com docs f Note Although this manual reflects the most current information possible read the Red Hat Enterprise Linux Release Notes for information that may not have been available prior to our documenta tion being finalized They can be found on the Red Hat Enterprise Linux CD 1 and online at http www redhat com docs 1 Changes to This Manual The previous version of this manual was named the Red Hat Linux Customization Guide It has been renamed the Red Hat Enterprise Linux System Administration Guide to better reflect the topics dis cussed as well as to more clearly define its role in the Red Hat documentation set Tt has been expanded to include new features in Red Hat Enterprise Linux 3 as well as topics request
248. igure each diskless client to boot via PXE and boot them 15 1 Start the tftp Server On the DHCP server verify that the t ftp server package is installed with the command rpm q tftp server If it is not installed install it via Red Hat Network or the Red Hat Enterprise Linux CD ROMs For more information on installing RPM packages refer to Part IN Package Management tftp is an xinetd based service start it with the following commands sbin chkconfig level 345 xinetd on sbin chkconfig level 345 tftp on This command configures the t ftp and xinetd services to immediately turned on and also configures them to start at boot time in runlevels 3 4 and 5 98 Chapter 15 Diskless Environments 15 2 Configuring the DHCP Server If a DHCP server does not already exist on the network configure one Refer to Chapter 25 Dy namic Host Configuration Protocol DHCP for details Make sure the configuration file contains the following so PXE booting is enabled for systems that support it allow booting allow bootp class pxeclients match if substring option vendor class identifier 0 9 PXEClient next server lt server ip gt filename linux install pxelinux 0 The IP address that follows the next server option should be the IP address of the t ftp server 15 3 Configuring the NFS Server The shared read only part of the operating system is shared via NFS Configure the NFS to export the root and snapshot d
249. igured with SSL support communications between an Apache HTTP Server and its clients are not encrypted This is appropriate for websites without personal or confidential information For example an open source website that distributes open source software and documentation has no need for secure communications However an ecommerce website that requires credit card information should use the Apache SSL support to encrypt its communications Enabling Apache SSL support enables the use of the mod_ss1 security module To enable it through HTTP Configuration Tool you must allow access through port 443 under the Main tab gt Available Chapter 26 Apache HTTP Server Configuration 199 Addresses Refer to Section 26 1 Basic Settings for details Then select the virtual host name in the Virtual Hosts tab click the Edit button choose SSL from the left hand menu and check the Enable SSL Support option as shown in Figure 26 9 The SSL Configuration section is pre configured with the dummy digital certificate The digital certificate provides authentication for your secure Web server and identifies the secure server to client Web browsers You must purchase your own digital certificate Do not use the dummy one provided for your website For details on purchasing a CA approved digital certificate refer to the Chapter 27 Apache HTTP Secure Server Configuration 26 3 1 3 Additional Virtual Host Options The Site Configuration Environment Variables and Di
250. ildcards Use the or character to specify a string match Wildcards are not to be used with IP addresses however they may accidentally work if reverse DNS lookups fail When specifying wildcards in fully qualified domain names dots are not included in the wildcard For example example com includes one example com but does not include one two example com IP networks Use a b c d z where a b c d is the network and z is the number of bits in the netmask for example 192 168 0 0 24 Another acceptable format is a b c d netmask where a b c d is the network and netmask is the netmask for example 192 168 100 8 255 255 255 0 Netgroups In the format group name where group name is the NIS netgroup name 23 3 3 Starting and Stopping the Server On the server that is exporting NFS file systems the nfs service must be running View the status of the NFS daemon with the following command sbin service nfs status Start the NFS daemon with the following command sbin service nfs start Stop the NFS daemon with the following command sbin service nfs stop To start the nfs service at boot time use the command Chapter 23 Network File System NFS 169 sbin chkconfig level 345 nfs on You can also use chkconfig ntsysv or the Services Configuration Tool to configure which services start at boot time Refer to Chapter 21 Controlling Access to Services for details 23 4 Additional Resources
251. ing gt Emacs to start the Emacs text editor iv Introduction button on a GUI screen or window This style indicates that the text can be found on a clickable button on a GUI screen For example Click on the Back button to return to the webpage you last viewed computer output Text in this style indicates text displayed to a shell prompt such as error messages and responses to commands For example The 1s command displays the contents of a directory For example Desktop about html logs paulwesterberg png Mail backupfiles mail reports The output returned in response to the command in this case the contents of the directory is shown in this style prompt A prompt which is a computer s way of signifying that it is ready for you to input something is shown in this style Examples stephen maturin stephen leopard login user input Text that the user has to type either on the command line or into a text box on a GUI screen is displayed in this style In the following example text is displayed in this style To boot your system into the text based installation program you must type in the text com mand at the boot prompt replaceable Text used for examples which is meant to be replaced with data provided by the user is displayed in this style In the following example lt version number gt is displayed in this style The directory for the kernel source is usr src lt version number gt whe
252. ing a list of items each identified by a keyword You can create it by editing a copy of the sample ks file found in the RH DOCS directory of the Red Hat En terprise Linux Documentation CD using the Kickstart Configurator application or writing it from scratch The Red Hat Enterprise Linux installation program also creates a sample kickstart file based on the options that you selected during installation It is written to the file root anaconda ks cfg You should be able to edit it with any text editor or word processor that can save files as ASCH text First be aware of the following issues when you are creating your kickstart file Sections must be specified in order Items within the sections do not have to be in a specific order unless otherwise specified The section order is Command section Refer to Section 9 4 Kickstart Options for a list of kickstart options You must include the required options The packages section Refer to Section 9 5 Package Selection for details The pre and post sections These two sections can be in any order and are not required Refer to Section 9 6 Pre installation Script and Section 9 7 Post installation Script for details 40 Chapter 9 Kickstart Installations Items that are not required can be omitted Omitting any required item will result in the installation program prompting the user for an answer to the related item just as the user would be prompted during a typica
253. ing list 16 password aging 243 forcing expiration of 243 PCI devices listing 297 physical extent 88 physical volume 13 87 pixels 237 postfix 289 PPPoE 128 Pre Execution Environment 91 printconf See printer configuration printer configuration 249 adding CUPS IPP printer 251 IPP printer 251 JetDirect printer 255 local printer 250 LPD printer 252 Novell NetWare NCP printer 255 Samba SMB printer 253 cancel print job 264 command line options 261 add a printer 261 remove a printer 261 restore configuration 260 save configuration 260 325 setting default printer 262 CUPS 249 default printer 258 delete existing printer 258 driver options 259 Effective Filter Locale 260 GhostScript pre filtering 260 Media Source 260 Page Size 260 Prerender Postscript 259 edit driver 259 edit existing printer 258 exporting settings 260 GNOME Print Manager 262 change printer settings 262 importing settings 260 IPP printer 251 JetDirect printer 255 local printer 250 managing print jobs 262 modifying existing printers 258 networked CUPS IPP printer 251 notification icon 263 Novell NetWare NCP printer 255 printing from the command line 264 remote LPD printer 252 rename existing printer 259 Samba SMB printer 253 save configuration to file 260 sharing 264 allowed hosts 265 system wide options 265 test page 258 text based application 249 viewing print spool 262 viewing
254. ion 37 2 5 Controlling Access to At and Batch for details 37 2 3 Viewing Pending Jobs To view pending at and batch jobs use the atq command It displays a list of pending jobs with each job on a line Each line follows the job number date hour job class and username format Users can only view their own jobs If the root user executes the atq command all jobs for all users are displayed 37 2 4 Additional Command Line Options Additional command line options for at and batch include Option Description o f Read the commands or shell script from a file instead of specifying them at the prompt Send email to the user when the job has been completed Display the time that the job will be executed Table 37 1 at and batch Command Line Options 37 2 5 Controlling Access to At and Batch The etc at allow and etc at deny files can be used to restrict access to the at and batch commands The format of both access control files is one username on each line Whitespace is not Chapter 37 Automated Tasks 271 permitted in either file The at daemon atd does not have to be restarted if the access control files are modified The access control files are read each time a user tries to execute the at or batch commands The root user can always execute at and batch commands regardless of the access control files If the file at allow exists only users listed in it are allowed to use at or batch and the at deny file
255. irective sets the hostname of the Web server It is used when creating redirection URLs If you do not define a server name the Web server attempts to resolve it from the IP address of the system The server name does not have to be the domain name resolved from the IP address of the server For example you might want to set the server name to www example com when your server s real DNS name is actually foo example com Enter the email address of the person who maintains the Web server in the Webmaster email address text area This option corresponds to the ServerAdmin directive in httpd conf If you configure the server s error pages to contain an email address this email address will be used so that users can report a problem by sending email to the server s administrator The default value is root localhost Use the Available Addresses area to define the ports on which the server will accept incoming re quests This option corresponds to the Listen directive in httpd conf By default Red Hat config ures the Apache HTTP Server to listen to port 80 for non secure Web communications Click the Add button to define additional ports on which to accept requests A window as shown in Figure 26 2 will appear Either choose the Listen to all addresses option to listen to all IP ad dresses on the defined port or specify a particular IP address over which the server will accept con nections in the Address field Only specify one IP address per por
256. irectories by adding them to etc exports For example diskless i386 RHEL3 AS root ro sync no_root_squash diskless i386 RHEL3 AS snapshot rw sync no_root_squash Replace with one of the hostname formats discussed in Section 23 3 2 Hostname Formats Make the hostname declaration as specific as possible so unwanted systems can not access the NFS mount If the NFS service is not running start it service nfs start If the NFS service is already running reload the configuration file service nfs reload 15 4 Finish Configuring the Diskless Environment To use the graphical version of the Network Booting Tool you must be running the X Window System have root privileges and have the redhat config netboot RPM package installed To start the Network Booting Tool from the desktop go to the Main Menu Button on the Panel gt System Settings gt Server Settings gt Network Booting Service Or type the command redhat config netboot ata shell prompt for example in an XTerm or a GNOME terminal If starting the Network Booting Tool for the first time select Diskless from the First Time Druid Otherwise select Configure gt Diskless from the pull down menu and then click Add A wizard appears to step you through the process 1 Click Forward on the first page 2 On the Diskless Identifier page enter a Name and Description for the diskless environment Click Forward 3 Enter the IP address or domain name of th
257. ired for the user specified in the User name field Click Forward to continue The Printer Configuration Tool then attempts to connect to the shared printer If the shared printer requires a username and password a dialog window appears prompting you to provide a valid username and password for the shared printer If an incorrect share name is specified you can change it here as well If a workgroup name is required to connect to the share it can be specified in this dialog box This dialog window is the same as the one shown when the Specify button is clicked Next select the printer type Refer to Section 36 7 Selecting the Printer Model and Finishing for details A waming If you require a username and password they are stored unencrypted in files only readable by root and Ipd Thus it is possible for others to learn the username and password if they have root access To avoid this the username and password to access the printer should be different from the username and password used for the user s account on the local Red Hat Enterprise Linux system If they are different then the only possible security compromise would be unauthorized use of the printer If there are file shares from the server it is recommended that they also use a different password than the one for the print queue Chapter 36 Printer Configuration 255 36 5 Adding a Novell NetWare NCP Printer To add a Novell NetWare NCP printer click the New button in
258. is ignored If at allow does not exist users listed in at deny are not allowed to use at or batch 37 2 6 Starting and Stopping the Service To start the at service use the command sbin service atd start To stop the service use the command sbin service atd stop It is recommended that you start the service at boot time Re fer to Chapter 21 Controlling Access to Services for details on starting the cron service automatically at boot time 37 3 Additional Resources To learn more about configuring automated tasks refer to the following resources 37 3 1 Installed Documentation cron man page overview of cron crontab man pages in sections 1 and 5 The man page in section 1 contains an overview of the crontab file The man page in section 5 contains the format for the file and some example entries e usr share doc at lt version gt timespec contains more detailed information about the times that can be specified for cron jobs at man page description of at and batch and their command line options 272 Chapter 37 Automated Tasks 3 redhat Chapter 38 Log Files Log files are files that contain messages about the system including the kernel services and appli cations running on it There are different log files for different information For example there is a default system log file a log file just for security messages and a log file for cron tasks Log files can be very useful when trying t
259. isk later the data contained in these samples can then be used to generate reports on system level and application level performance eee The kernel support for OProfile in Red Hat Enterprise Linux 3 is based on the back ported code from the 2 5 development kernel When referring to OProfile documentation 2 5 specific features apply to OProfile in Red Hat Enterprise Linux 3 even though the kernel version is 2 4 Likewise OProfile features specific to the 2 4 kernel do not apply to Red Hat Enterprise Linux 3 OProfile is a useful tool but be aware of some limitations when using it Use of shared libraries Samples for code in shared libraries are not attributed to the particular application unless the separate library option is used Performance monitoring samples are inexact When a performance monitoring register triggers a sample the interrupt handling is not precise like a divide by zero exception Due to the out of order execution of instructions by the processor the sample may be recorded on a nearby instruction oprofpp does not associate samples for inline functions properly oprofpp uses a simple address range mechanism to determine which function an address is in Inline function samples are not attributed to the inline function but rather to the function the inline function was inserted into OProfile accumulates data from multiple runs OProfile is a system wide profiler and expects processes to star
260. isplay Advanced Monitor Monitor Type ViewSonic G773 Configure F Horizontal Refresh Rates kHz 30 0 70 0 Vertical Refresh Rates Hz 50 0 160 0 DPI physical resolution 81 by 81 dots perinch Set DPI Video Card Video Card Type S3 VIRGE generic Configure agp Memory Size 4 megabytes Driver s3virge Enable Hardware 3D Acceleration 38 Cancel OK Figure 34 2 Advanced Settings To change the monitor type or any of its settings click the corresponding Configure button To change the video card type or any of its settings click the Configure button beside its settings 3 redhat Chapter 35 User and Group Configuration The User Manager allows you to view modify add and delete local users and groups To use the User Manager you must be running the X Window System have root privileges and have the redhat config users RPM package installed To start the User Manager from the desktop go to the Main Menu Button on the Panel gt System Settings gt Users amp Groups Or type the command redhat config users at a shell prompt for example in an XTerm or a GNOME terminal Eile Preferences Help B Add User Add Group Properties Delete Help Refresh Search filter Apply filter Users User Name User ID Primary Group Full Name tfox 500 tfox Tammy Fox bin bash home tfox bfox 501 bfox Brent Fox bin bash home bfox Login Shell
261. isted or add the directive default and set it to the label of the image stanza that contains the new kernel Begin testing the new kernel by rebooting the computer and watching the messages to ensure that the hardware is detected properly 284 Chapter 39 Upgrading the Kernel redhat Chapter 40 Kernel Modules The Linux kernel has a modular design At boot time only a minimal resident kernel is loaded into memory Thereafter whenever a user requests a feature that is not present in the resident kernel a kernel module sometimes referred to as a driver is dynamically loaded into memory During installation the hardware on the system is probed Based on this probing and the information provided by the user the installation program decides which modules need to be loaded at boot time The installation program sets up the dynamic loading mechanism to work transparently If new hardware is added after installation and the hardware requires a kernel module the system must be configured to load the proper kernel module for the new hardware When the system is booted with the new hardware the Kudzu program runs detects the new hardware if it is supported and configures the module for it The module can also be specified manually by editing the module configuration file etc modules conf f Note Video card modules used to display the X Window System interface are part of the xFree86 package not the kernel thus this chapter does not
262. itions in the Red Hat Enterprise Linux Installation Guide For example to create a primary partition with an ext3 file system from 1024 megabytes until 2048 megabytes on a hard drive type the following command mkpart primary ext3 1024 2048 If you use the mkpart fs command instead the file system is created after the partition is created However parted does not support creating an ext3 file system Thus if you wish to create an ext3 file system use mkpart and create the file system with the mkfs command as described later mkpart fs works for file system type linux swap The changes start taking place as soon as you press Enter so review the command before executing to it After creating the partition use the print command to confirm that it is in the partition table with the correct partition type file system type and size Also remember the minor number of the new partition so that you can label it You should also view the output of cat proc partitions to make sure the kernel recognizes the new partition 5 2 2 Formating the Partition The partition still does not have a file system Create the file system sbin mkfs t ext3 dev hdb3 18 Chapter 5 Managing Disk Storage A waming Formatting the partition permanently destroys any data that currently exists on the partition 5 2 3 Labeling the Partition Next give the partition a label For example if the new partition is dev hda3 and you want to la
263. its the dot character or the slash character such as ab or 12 import crypt print crypt crypt password salt The output is the encrypted password similar to 12CsGd8FRcMSM Type Ctrl D to exit the Python interpreter Cut and paste the exact encrypted password output without a leading or trailing blank spaces into the following command usermod p encrypted password username Instead of assigning an initial password a null password can be assigned using the command usermod p username Caution While using a null password is convenient for both the user and the administrator there is a slight risk that a third party can log in first and access the system To minimize this threat it is recommended that the administrator verifies that the user is ready to log in when the account is unlocked In either case upon initial log in the user is prompted for a new password 35 6 Explaining the Process The following steps illustrate what happens if the command useradd juan is issued on a system that has shadow passwords enabled 1 A new line for juan is created in etc passwd The line has the following characteristics e It begins with the username juan There is an x for the password field indicating that the system is using shadow passwords A UID at or above 500 is created Under Red Hat Enterprise Linux UIDs and GIDs below 500 are reserved for system use A GID at or above 500 is created
264. its short description change the value in the Queue name tab Click OK to return to the main window The name of the printer should change in the printer list Click Apply to save the change and restart the printer daemon 36 9 2 Queue Type The Queue type tab shows the queue type that was selected when adding the printer and its settings The queue type of the printer can be changed or just the settings After making modifications click OK to return to the main window Click Apply to save the changes and restart the printer daemon Depending on which queue type is chosen different options are displayed Refer to the appropriate section on adding a printer for a description of the options 36 9 3 Printer Driver The Printer driver tab shows which print driver is currently being used If it is changed click OK to return to the main window Click Apply to save the change and restart the printer daemon 36 9 4 Driver Options The Driver Options tab displays advanced printer options Options vary for each print driver Com mon options include Prerender Postscript should be selected if characters beyond the basic ASCH set are being sent to the printer but they are not printing correctly such as Japanese characters This option prerenders non standard PostScript fonts so that they are printed correctly If the printer does not support the fonts you are trying to print try selecting this option For example select this option to print
265. ity using a single virtual disk Lessened impact of a disk failure 3 3 Hardware RAID versus Software RAID There are two possible RAID approaches Hardware RAID and Software RAID 3 3 1 Hardware RAID The hardware based system manages the RAID subsystem independently from the host and presents to the host only a single disk per RAID array An example of a Hardware RAID device would be one that connects to a SCSI controller and presents the RAID arrays as a single SCSI drive An external RAID system moves all RAID handling intelli gence into a controller located in the external disk subsystem The whole subsystem is connected to the host via a normal SCSI controller and appears to the host as a single disk RAID controllers also come in the form of cards that act like a SCSI controller to the operating system but handle all of the actual drive communications themselves In these cases you plug the drives into the RAID controller just like you would a SCSI controller but then you add them to the RAID controller s configuration and the operating system never knows the difference 10 Chapter 3 Redundant Array of Independent Disks RAID 3 3 2 Software RAID Software RAID implements the various RAID levels in the kernel disk block device code It offers the cheapest possible solution as expensive disk controller cards or hot swap chassis are not re quired Software RAID also works with cheaper IDE disks as well as SCSI disks Wi
266. iver diskettes can be used during kickstart installations You need to copy the driver diskettes s contents to the root directory of a partition on the system s hard drive Then you need to use the driverdisk command to tell the installation program where to look for the driver disk driverdisk lt partition gt type lt fstype gt Alternatively a network location can be specified for the driver diskette driverdisk source ftp path to dd img driverdisk source http path to dd img driverdisk source nfs host path to img lt partition gt Partition containing the driver disk type File system type for example vfat or ext2 firewall optional This option corresponds to the Firewall Configuration screen in the installation program firewall enabled disabled trust lt device gt port enabled Reject incoming connections that are not in response to outbound requests such as DNS replies or DHCP requests If access to services running on this machine is needed you can choose to allow specific services through the firewall disabled Do not configure any iptables rules lt trEust Listing a device here such as eth0 allows all traffic coming from that device to go through the firewall To list more than one device use trust ethO trust eth1 Do NOT use a comma separated format such as trust eth0 ethl lt incoming gt Replace with none or more of the following to allow the spe
267. jG You may configure network devices associated with 3 oo physical hardware here Multiple logical devices can be 5 associated with a single piece of hardware Nickname Figure 19 15 Wireless Device Be sure to select File gt Save to save the changes After adding the wireless device you can edit its configuration by selecting the device from the device list and clicking Edit For example you can configure the device to activate at boot time When the device is added it is not activated immediately as seen by its Inactive status To activate the device select it from the device list and click the Activate button If the system is configured to activate the device when the computer starts the default this step does not have to be performed again 19 9 Managing DNS Settings The DNS tab allows you to configure the system s hostname domain name servers and search do main Name servers are used to look up other hosts on the network If the DNS server names are retrieved from DHCP or PPPoE or retrieved from the ISP do not add primary secondary or tertiary DNS servers If the hostname is retrieved dynamically from DHCP or PPPoE or retrieved from the ISP do not change it Eile Profile Help BBS New Edit Copy Delete Devices Hardware IPsec DNS Hosts You may configure the system s hostname domain name servers and search domain Name serv
268. k is created from the user defined device name to the actual device name If the actual device name changes the symbolic link is updated to point to the same drive according to its UUID Thus both IDE and SCSI storage devices can be referenced by their user defined names Devlabe1 also allows for automatically mounting hotplug devices such as removable hard drives and USB devices such as memory cards for digital cameras If configured to mount automatically after the device is plugged in it is mounted with the user defined device name 7 1 Configuring Devlabel User defined device names can be added based on the device name partition name or the UUID of the drive Use the following syntax to add a user defined device name for a storage device The device specified can be the entire device or a single partition on a device 28 Chapter 7 User Defined Device Names devlabel add d lt device gt s lt symlink gt For example to add the symbolic link dev work to represent the dev hdb1 partition use the following command devlabel add d dev hdbl s dev work If the command was successful the following is displayed Created symlink dev work gt dev hdb1 Added dev work to etc sysconfig devlabel To add a device name for a device based on a UUID use the following syntax devlabel add u lt uuid gt s lt symlink gt To use devlabel to retrieve the UUID for a device or to make sure it has one use the following comman
269. l How ever you must use the dd command to configure the system to boot the new kernel 1 As root issue the command cat proc iSeries mf side to determine the default side either A B or C 2 As root issue the following command where lt kernel version gt is the version of the new kernel and lt side gt is the side from the previous command dd if boot vmlinitrd lt kernel version gt of proc iSeries mf lt side gt vmlinux bs 8k Begin testing the new kernel by rebooting the computer and watching the messages to ensure that the hardware is detected properly 39 6 5 IBM eServer pSeries Systems IBM eServer pSeries systems use YABOOT as the boot loader which uses etc aboot conf as the configuration file Confirm that the file contains an image section with the same version as the kernel package just installed boot dev sdal init message Welcome to Red Hat Enterprise Linux Hit lt TAB gt for boot options partition 2 timeout 30 install usr lib yaboot yaboot delay 10 nonvram image vmlinux 2 4 20 2 30 ent label old read only initrd initrd 2 4 20 2 30 ent img append root LABEL image vmlinux 2 4 21 1 1931 2 399 ent label linux read only initrd initrd 2 4 21 1 1931 2 399 ent img append root LABEL Notice that the default is not set to the new kernel The kernel in the first image is booted by default To change the default kernel to boot either move its image stanza so that it is the first one l
270. l Resources For more information on kernel modules and their utilities refer to the following resources 40 2 1 Installed Documentation lsmod man page description and explanation of its output e insmod man page description and list of command line options modprobe man page description and list of command line options rmmod man page description and list of command line options e modinfo man page description and list of command line options e usr src linux 2 4 Documentat ion modules txt how to compile and use kernel mod ules This file is part of the kernel source package 40 2 2 Useful Websites http www redhat com mirrors LDP HOWTO Module HOWTO index html Linux Loadable Kernel Module HOWTO from the Linux Documentation Project 288 Chapter 40 Kernel Modules redhat Chapter 41 Mail Transport Agent MTA Configuration A Mail Transport Agent MTA is essential for sending email A Mail User Agent MUA such as Evolution Mozilla Mail and Mutt is used to read and compose email When a user sends an email from an MUA the messages are handed off to the MTA which sends the message to a series of MTAs until it reaches its destination Even if a user does not plan to send email from the system some automated tasks or system programs might use the bin mail command to send email containing log messages to the root user of the local system Red Hat Enterprise Linux 3 provides two MTAs
271. l installation Once the answer is given the installation will continue unattended unless it finds another missing item Lines starting with a pound sign are treated as comments and are ignored For kickstart upgrades the following items are required Language Language support Installation method Device specification if device is needed to perform installation Keyboard setup The upgrade keyword Boot loader configuration If any other items are specified for an upgrade those items will be ignored note that this includes package selection 9 4 Kickstart Options The following options can be placed in a kickstart file If you prefer to use a graphical interface for creating your kickstart file you can use the Kickstart Configurator application Refer to Chapter 10 Kickstart Configurator for details Note If the option is followed by an equals mark a value must be specified after it In the example commands options in brackets are optional arguments for the command autopart optional Automatically create partitions 1 GB or more root partition a swap partition and an appropriate boot partition for the architecture One or more of the default partition sizes can be redefined with the part directive autostep optional Similar to interact ive except it goes to the next screen for you It is used mostly for debug ging auth or authconfig required Sets up the authentication
272. l the subdirectories use the command du hs to see only the grand total for the directory in human readable format Use the du help command to see more options Chapter 42 Gathering System Information 297 To view the system s partitions and disk space usage in a graphical format use the System Monitor tab as shown at the bottom of Figure 42 2 42 4 Hardware If you are having trouble configuring your hardware or just want to know what hardware is in your system you can use the Hardware Browser application to display the hardware that can be probed To start the program from the desktop select Main Menu Button gt System Tools gt Hardware Browser or type hwbrowser at a shell prompt As shown in Figure 42 3 it displays your CD ROM devices floppy disks hard drives and their partitions network devices pointing devices system de vices and video cards Click on the category name in the left menu and the information will be displayed CD ROM Drives Selected Device Floppy Disks CRD amp 482B Hard Drives Network devices System devices USB devices Video cards Device Information Manufacturer Unknown Driver none or built in Device dev hdc Figure 42 3 Hardware Browser You can also use the 1spci command to list all PCI devices Use the command lspci v for more verbose information or lspci vv for very verbose output For example 1spci can be used to determine the manufacturer model and memory size
273. led Click Forward to continue 7 On the Local Network page enter the following information Local Network Address The IP address of the device on the IPsec router connected to the private network Local Subnet Mask The subnet mask of the local network IP address Local Network Gateway The gateway for the private subnet Click Forward to continue IPsec Local Network Please enter your local network settings Local Network Address 192 168 1 3 Local Subnet Mask 255 255 255 0 Local Network Gateway 172 31 1 1 3 Cancel lt Back gt Forward Figure 19 24 Local Network Information 144 Chapter 19 Network Configuration 8 On the Remote Network page enter the following information Remote IP Address The publically addressable IP address of the IPsec router for the other private network In our example for ipsecO enter the publically addressable IP address of ipsecl and vice versa Remote Network Address The network address of the private subnet behind the other IPsec router In our example enter 192 168 1 0 if configuring ipsecl and enter 192 168 2 0 if configuring ipsec0 Remote Subnet Mask The subnet mask of the remote IP address Remote Network Gateway The IP address of the gateway for the remote network address If manual encryption was selected in step 6 specify the encryption key to use or click Gen erate to create one S
274. led or upgraded from the RPM packages distributed by Red Hat Inc thus it does not need to be executed manually To verify that it was created use the command 1s 1 boot to make sure the boot vmlinitrd lt kernel version gt file was created the version should match the version of the kernel just installed The next step is to verify that the boot loader has been configured to boot the new kernel Refer to Section 39 6 Verifying the Boot Loader for details 39 6 Verifying the Boot Loader The kernel RPM package configures the boot loader to boot the newly installed kernel except for IBM eServer iSeries systems However it does not configure the boot loader to boot the new kernel by default It is always a good idea to confirm that the boot loader has been configured correctly This is a crucial step If the boot loader is configured incorrectly the system will not boot into Red Hat Enterprise Linux properly If this happens boot the system with the boot diskette created earlier and try config uring the boot loader again 39 6 1 x86 Systems x86 systems have the option of using GRUB or LILO as the boot loader with one exception AMD64 systems do not have the option of using LILO For all x86 systems GRUB is the default Chapter 39 Upgrading the Kernel 281 39 6 1 1 GRUB If GRUB is used as the boot loader confirm that the file boot grub grub conf contains a title section with the same version as the kernel package jus
275. line http www modssl org The mod_ss1 website is the definitive source for information about mod_ssl The website includes a wealth of documentation including a User Manual at http www modssl org docs 27 11 2 Related Books Apache The Definitive Guide 2nd edition by Ben Laurie and Peter Laurie O Reilly amp Associates Inc redhat Chapter 28 BIND Configuration This chapter assumes that the reader has a basic understanding of BIND and DNS it does not attempt to explain the concepts of BIND and DNS This chapter does explain how to use the Domain Name Service Configuration Tool redhat config bind to configure basic BIND server zones The Domain Name Service Configuration Tool creates the etc named conf configuration file and the zone configuration files in the var named directory each time changes are applied Broren Do not edit the etc named conf configuration file Domain Name Service Configuration Tool generates this file after changes are applied To configure settings that are not configurable using Domain Name Service Configuration Tool add them to the etc named custom file The Domain Name Service Configuration Tool requires the X Window System and root access To start the Domain Name Service Configuration Tool go to the Main Menu Button on the Panel gt System Settings gt Server Settings gt Domain Name Service or type the command redhat config bind at a shell prompt for example in
276. ll reboot your system automatically after the installa tion is finished Kickstart installations are performed in graphical mode by default To override this default and use text mode instead select the Perform installation in text mode option You can perform a kickstart installation in interactive mode This means that the installation program uses all the options pre configured in the kickstart file but it allows you to preview the options in each screen before continuing to the next screen To continue to the next screen click the Next button after you have approved the settings or change them before continuing the installation To select this type of installation select the Perform installation in interactive mode option 10 2 Installation Method File Help Basic Configuration Installation Method required Perform new installation Boot Loader Options Upgrade an existing installation Partition Information Choose the Installation Method Network Configuration CD ROM Authentication ONFS Firewall Configuration OFTeP X Configuration O HTP Package Selection O Hard Drive Pre Installation Script Post installation Script Figure 10 2 Installation Method Chapter 10 Kickstart Configurator 65 The Installation Method screen allows you to choose whether to perform a new installation or an upgrade If you choose upgrade the Partition Information and Package Selection options will be disabled They are not supported fo
277. mand on the remote machine without logging in to a shell prompt The syntax is ssh hostname command For example if you want to execute the command 1s usr share doc on the remote machine penguin example net type the following command at a shell prompt ssh penguin example net ls usr share doc After you enter the correct password the contents of the remote directory usr share doc will be displayed and you will return to your local shell prompt 22 3 2 Using the scp Command The scp command can be used to transfer files between machines over a secure encrypted connection It is similar to rcp The general syntax to transfer a local file to a remote system is as follows scp localfile username tohostname newfilename The localfile specifies the source and username tohostname newfilename specifies the destination Chapter 22 OpenSSH 159 To transfer the local file shadowman to your account on penguin example net type the following at a shell prompt replace username with your username scp shadowman username penguin example net home username This will transfer the local file shadowman to home username shadowman on penguin example net The general syntax to transfer a remote file to the local system is as follows scp username tohostname remotefile newlocalfile The remotefile specifies the source and newlocal file specifies the destination Multiple files can be specified as the source files For example to trans
278. manually more details about the Apache HTTP Server directives and instructions for adding modules to the Apache HTTP Server redhat Chapter 27 Apache HTTP Secure Server Configuration 27 1 Introduction This chapter provides basic information on the Apache HTTP Server with the mod_ss1 security module enabled to use the OpenSSL library and toolkit The combination of these three components are referred to in this chapter as the secure Web server or just as the secure server The mod_ss1 module is a security module for the Apache HTTP Server The mod_ss1 module uses the tools provided by the OpenSSL Project to add a very important feature to the Apache HTTP Server the ability to encrypt communications In contrast using regular HTTP communications between a browser and a Web server are sent in plain text which could be intercepted and read by someone along the route between the browser and the server This chapter is not meant to be complete and exclusive documentation for any of these programs When possible this guide points to appropriate places where you can find more in depth documenta tion on particular subjects This chapter shows you how to install these programs You can also learn the steps necessary to generate a private key and a certificate request how to generate your own self signed certificate and how to install a certificate to use with your secure server The mod_ss1 configuration file is located at etc ht
279. mation 10 5 Network Configuration 10 6 Authentication 10 7 Firewall Configuration a 10 8 X Confi Suration 3 2 00 scscesecccthessdseedesceceveesvicdsveddanssvesstecsaledsussssidececedanssissevscsdeedetse 10 9 P ck ge Selection ine rrer niii ei EA E EEEE E 10 10 Pre Installation Script ne 10 11 Post Installation Scripter iiser arresti P EEES 76 10 12 Saving the File sioe a e aari ERIE AKATERE TEE EATER svivesetesavseataa 78 11 Basic System Recovery wld 11 1 Common Problems 79 11 2 Booting into Rescue Mode 79 11 3 Booting into Single User Mode 11 4 Booting into Emergency Mode 82 12 Software RAID Configuration 83 13 LVM Configuration 87 14 PXE Network Installations 0 0 00 91 14 1 Setting up the Network Server cece eecseeeeeeeeseseseseeecessesesseesesssseneees 91 14 2 PXE Boot Comfiguration csscsvsccccccsccessisesccecccssensstesesccscesesassetteaconssansetavesecaatenes 91 14 3 Adding PXE Hosts ws 14 4 Starting the t ftp Ser VE enone i KA AA SSE AIA SEAS 94 14 5 Configuring the DHCP Serye soeren a a a E a 94 14 6 Adding a Custom Boot Message 14 7 Performing the PXE Installation 15 Diskless Environments 15 1 Start the t ftp Server 97 15 2 Configuring the DHCP Server 97 15 3 Configuring the NFS Servet v sscccccsesssssvccceseessenessvencsaonssonovsvesevsssovesduececco
280. met X Configuration Matrox Marvel II Package Selection Matrox Millennium Pre Installation Script Matrox Millennium G200 Post Installation Script Matrox Millennium G400 Matrox Millennium G450 Matrox Millennium G550 Matrox Millennium II Matrox Mystique Matrox Mystique G200 Matrox Productiva G100 MediaVision Proaxcel 128 Mirage Z 128 Miro CRYSTAL VRX Miro Crystal 10SD with GenDAC Miro Crystal 12SD Miro Crystal 16S Video Card RAM b2 MB v Figure 10 12 X Configuration Video Card 10 8 3 Monitor After configuring the video card click on the Monitor tab as shown in Figure 10 13 Eile Help Basic Configuration X Configuration Installation Method Configure the X Window System Boot Loader Options General Video Card Monitor Partition Information Probe for monitor Netiiork ENUE ViewSonic OptiQuest V55 a Authentication ViewSonic OptiQuest V641 Firewall Configuration ViewSonic OptiQuest V655 2 ViewSonic OptiQuest V655 3 Package selection ViewSonic OptiQuest V655 ViewSonic OptiQuest V73 ViewSonic OptiQuest V75 ViewSonic OptiQuest V773 2 ViewSonic OptiQuest V775 2 ViewSonic OptiQuest V775 ViewSonic OptiQuest V95 ViewSonic OptiQuest VA656 ViewSonic P655 ViewSonic P775 Pre Installation Script Post Installation Script ViewSonic P795 5 Specify hsync and vsync instead of monitor Horizo
281. migration 0 3 root RT 0 0 0 0 SW 0 0 0 0 0 00 1 migration 1 4 root 19 0 0 0 0 SW 0 0 0 0 0 00 0 keventd 5 root 34 19 0 0 0 SWN 0 0 0 0 0 00 0 ksoftirqd 0 6 root 34 19 0 0 0 SWN 0 0 0 0 0 00 1 ksoftirqd 1 9 root 25 0 0 0 0 SW 0 0 0 0 0 00 0 bdflush 7 root 15 0 0 0 0 SW 0 0 0 0 0 00 1 kswapd 8 root ES 0 0 0 0 SW 0 0 0 0 0 00 1 kscand 10 root 15 0 0 0 0 SW 0 0 0 0 0 01 1 kupdated 11 root 25 0 0 0 0 SW 0 0 0 0 0 00 0 mdrecoveryd To exit top press the q key Useful interactive commands that you can use with top include the following 294 Chapter 42 Gathering System Information Immediately refresh the display Display a help screen Kill a process You will be prompted for the process ID and the signal to send to it Change the number of processes displayed You will be prompted to enter the number Sort by memory usage P Sort by CPU usage Table 42 1 Interactive top commands Qi Application such as Mozilla and Nautilus are thread aware multiple threads are created to handle multiple users or multiple requests and each thread is given a process ID By default ps and top only display the main initial thread To view all threads use the command ps m or type Shift H in top If you prefer a graphical interface for top you can use the GNOME System Monitor To start it from the desktop select Main Menu Button on the Panel gt System Tools gt System Monitor or type gnome system monitor at a shell prompt
282. mmand as root redhat config network cmd e gt tmp network config To restore or import the network configuration from the file created from the previous command execute the following command as root redhat config network cmd i c f tmp network config The i option means to import the data the c option means to clear the existing configuration prior of importing and the option specifies that the file to import is as follows 146 Chapter 19 Network Configuration redhat Chapter 20 Basic Firewall Configuration Just as a firewall in a building attempts to prevent a fire from spreading a computer firewall attempts to prevent computer viruses from spreading to your computer and to prevent unauthorized users from accessing your computer A firewall exists between your computer and the network It determines which services on your computer remote users on the network can access A properly configured firewall can greatly increase the security of your system It is recommended that you configure a firewall for any Red Hat Enterprise Linux system with an Internet connection 20 1 Security Level Configuration Tool During the Firewall Configuration screen of the Red Hat Enterprise Linux installation you were given the option to enable a basic firewall as well as allow specific devices incoming services and ports After installation you can change this preference by using the Security Level Configuration Tool To star
283. mmand to execute a custom script For any of the above values an asterisk can be used to specify all valid values For example an asterisk for the month value means execute the command every month within the constraints of the other values A hyphen between integers specifies a range of integers For example 1 4 means the integers 1 2 3 and 4 A list of values separated by commas specifies a list For example 3 4 6 8 indicates those four specific integers The forward slash can be used to specify step values The value of an integer can be skipped within a range by following the range with lt integer gt For example 0 59 2 can be used to define every other minute in the minute field Step values can also be used with an asterisk For instance the value 3 can be used in the month field to run the task every third month Any lines that begin with a hash mark are comments and are not processed As shown in the etc crontab file it uses the run parts script to execute the scripts in the etc cron hourly etc cron daily etc cron weekly and etc cron monthly direc tories on an hourly daily weekly or monthly basis respectively The files in these directories should be shell scripts If a cron task needs to be executed on a schedule other than hourly daily weekly or monthly it can be added to the etc cron d directory All files in this directory use the same syntax as etc crontab Refer to Example 37
284. mmary list as shown in Fig ure 12 4 At this point you can continue with your installation process Refer to the Red Hat Enterprise Linux Installation Guide for further instructions Online Help Disk Setup Choose where you would like Red Hat Linux to be installed Ifyou do not know how to partition your system or if you need help with using the manual partitioning tools refer to the Red Hat Linux Installation Guide Ifyou used automatic partitioning you can either accept the current partition settings click Next or modify the setup using the manual partitioning tool Ifyou are manually partitioning your system you will see your current hard drive s and partitions displayed below Use Partitioning Drive dev hda Geom 2482 255 63 Model Maxtor 52049H3 Ihdaz hhda3 2996 mB 2996 MB Indas 13374 MB Drive dev hdb Geom 2482 255 63 Model Maxtor 52049H3 hdb1 hdb2 Free 4000 ME 2047 we 13421 MB New Eat Delete Rese Rao ivm Device A Type Format ae Start End v RAID Devices Jdev md0 home ext3 v 5993 7 Hard Drives V dev hda dev hda boot ext3 v 12 1 it dev hdaz dev mdo software RAID 2996 14 395 Idev hda3 dev md0 software RAID 2996 396 777 V dev hdat Extended 13374 778 2482 sinari w Pn I JE rtitioning tool to add edit v C Hide RAID device LVM Volume Group members Figu
285. mory RAM is full If the system needs more memory resources and the physical memory is full inactive pages in memory are moved to the swap space While swap space can help machines with a small amount of RAM it should not be considered a replacement for more RAM Swap space is located on hard drives which have a slower access time than physical memory Swap space can be a dedicated swap partition recommended a swap file or a combination of swap partitions and swap files The size of your swap space should be equal to twice your computer s RAM or 32 MB whichever amount is larger but no more than 2048 MB or 2 GB 2 2 Adding Swap Space Sometimes it is necessary to add more swap space after installation For example you may upgrade the amount of RAM in your system from 64 MB to 128 MB but there is only 128 MB of swap space It might be advantageous to increase the amount of swap space to 256 MB if you perform memory intense operations or run applications that require a large amount of memory You have two options add a swap partition or add a swap file It is recommended that you add a swap partition but that can be difficult if you do not have any free space available To add a swap partition assuming dev hdb2 is the swap partition you want to add 1 The hard drive can not be in use partitions can not be mounted and swap space can not be enabled The partition table should not be modified while in use because the kernel
286. multiple times and is converted to a format that the printer can not understand To make sure the data is not filtered more than once first try selecting Generic as the manufacturer and Raw Print Queue or Postscript Printer as the printer model After applying the changes print a test page to try out this new configuration If the test fails the remote print server might not have a print driver configured Try selecting a print driver according to the manufacturer and model of the remote printer applying the changes and printing a test page OG You can select a different print driver after adding a printer by starting the Printer Configuration Tool selecting the printer from the list clicking Edit clicking the Driver tab selecting a different print driver and then applying the changes 36 7 1 Confirming Printer Configuration The last step is to confirm your printer configuration Click Apply to add the print queue if the settings are correct Click Back to modify the printer configuration Click the Apply button in the main window to save your changes and restart the printer daemon After applying the changes print a test page to ensure the configuration is correct Refer to Section 36 8 Printing a Test Page for details If you need to print characters beyond the basic ASCII set including those used for languages such as Japanese you must review your driver options and select Prerender Postscript Refer to Section 36 9 Modifyi
287. n be one of ext2 ext3 FAT hfs jfs linux swap ntfs reiserfs hp ufs sun ufs or xfs The Flags column lists the flags set for the partition Available flags are boot root swap hidden raid lvm or lba Qr To select a different device without having to restart partea use the select command followed by the device name such as dev hdb Then you can view its partition table or configure it 5 2 Creating a Partition waming Do not attempt to create a partition on a device that is in use Before creating a partition boot into rescue mode or unmount any partitions on the device and turn off any swap space on the device Chapter 5 Managing Disk Storage 17 Start parted where dev hda is the device on which to create the partition parted dev hda View the current partition table to determine if there is enough free space print If there is not enough free space you can resize an existing partition Refer to Section 5 4 Resizing a Partition for details 5 2 1 Making the Partition From the partition table determine the start and end points of the new partition and what partition type it should be You can only have four primary partitions with no extended partition on a device If you need more than four partitions you can have three primary partitions one extended partition and multiple logical partitions within the extended For an overview of disk partitions refer to the appendix An Introduction to Disk Part
288. n existing kickstart file select File gt Open and select the existing file 10 1 Basic Configuration File Help Basic Configuration Basic Configuration required Installation Method Default Language English lv Bont ronder Optiens Keyboard U S English v Partition Information Network Configuration Mouse Generic 3 Button Mouse PS 2 lt Authentication Emulate 3 Buttons Firewall Configuration TE Time Zone America New_York A X Configuration Package Selection O Use UTC clock Pre Installation Script ies T Post nstallation Script Confirm Password Encrypt root password Language Support 7 Chinese Mainland 2 C Chinese Taiwan Czech C Danish Dutch English 7 Reboot system after installation C Perform installation in text mode graphical is default Perform installation in interactive mode Figure 10 1 Basic Configuration Choose the language to use during the installation and as the default language after installation from the Default Language menu Select the system keyboard type from the Keyboard menu Choose the mouse for the system from the Mouse menu If No Mouse is selected no mouse will be configured If Probe for Mouse is selected the installation program tries to auto detect the mouse Probing works for most modern mice If the system has a two button mouse a three button mouse can b
289. n on the system immediately after the ks cfg has been parsed This section must be at the end of the kickstart file after the commands and must start with the pre command You can access the network in the pre section however name service has not been configured at this point so only IP addresses will work f Note Note that the pre install script is not run in the change root environment interpreter usr bin python Allows you to specify a different scripting language such as usr bin python with the scripting language of your choice 9 6 1 Example Here is an example pre section Spre bin sh hds mymedia for file in proc ide h do mymedia cat file media if mymedia disk then hds hds basename file fi done set hds numhd echo drivel echo hds cut d f1 drive2 echo hds cut d f2 Python Write out partition scheme based on whether there are 1 or 2 hard drives if Snumhd 2 then 2 drives Replace echo partitioning scheme generated in pre for 2 drives gt tmp part include echo clearpart all gt gt tmp part include echo part boot fstype ext3 size 75 ondisk hda gt gt tmp part include echo part fstype ext3 size 1 grow ondisk hda gt gt tmp part include Chapter 9 Kickstart Installations 57 echo part swap recommended ondisk drivel gt gt tmp part i
290. n the BOOTP DHCP server you use Here is an example of a line from the dhcpd conf file for the DHCP server filename usr new machine kickstart next server blarg redhat com Note that you should replace the value after filename with the name of the kickstart file or the directory in which the kickstart file resides and the value after next server with the NFS server name If the filename returned by the BOOTP DHCP server ends with a slash then it is interpreted as a path only In this case the client system mounts that path using NFS and searches for a particular file The filename the client searches for is lt ip addr gt kickstart The lt ip addr gt section of the filename should be replaced with the client s IP address in dotted decimal notation For example the filename for a computer with an IP address of 10 10 0 1 would be 10 10 0 1 kickstart Note that if you do not specify a server name then the client system will attempt to use the server that answered the BOOTP DHCP request as its NFS server If you do not specify a path or filename the client system will try to mount kickstart from the BOOTP DHCP server and will try to find the kickstart file using the same lt ip addr gt kickstart filename as described above 9 9 Making the Installation Tree Available The kickstart installation needs to access an installation tree An installation tree is a copy of the binary Red Hat Enterprise Linux CD ROMs with th
291. nclude echo part home fstype ext3 size 1 grow ondisk hdb gt gt tmp part include else 1 drive echo partitioning scheme generated in pre for 1 drive gt tmp part include echo clearpart all gt gt tmp part include echo part boot fstype ext3 size 75 gt gt tmp part includ echo part swap recommended gt gt tmp part include echo part fstype ext3 size 2048 gt gt tmp part include echo part home fstype ext3 size 2048 grow gt gt tmp part include fi This script determines the number of hard drives in the system and writes a text file with a differ ent partitioning scheme depending on whether it has one or two drives Instead of having a set of partitioning commands in the kickstart file include the line sinclude tmp part include The partitioning commands selected in the script will be used 9 7 Post installation Script You have the option of adding commands to run on the system once the installation is complete This section must be at the end of the kickstart file and must start with the post command This section is useful for functions such as installing additional software and configuring an additional nameserver Note If you configured the network with static IP information including a nameserver you can access the network and resolve IP addresses in the spost section If you configured the network for DHCP the etc resolv conf fil
292. ncy with regard to the state of the file system Speed Despite writing some data more than once ext3 has a higher throughput in most cases than ext2 because ext3 s journaling optimizes hard drive head motion You can choose from three journaling modes to optimize speed but doing so means trade offs in regards to data integrity Easy Transition It is easy to change from ext2 to ext3 and gain the benefits of a robust journaling file system without reformatting Refer to Section 1 3 Converting to an ext3 File System for more on how to perform this task If you performed a fresh installation the default file system assigned to the system s Linux partitions is ext3 If you upgrade from a version that uses ext2 partitions the installation program allows you to convert these partitions to ext3 partitions without losing data Refer to the appendix titled Upgrading Your Current System in the Red Hat Enterprise Linux Installation Guide for details The following sections walk you through the steps for creating and tuning ext3 partitions For ext2 partitions skip the partitioning and formating sections below and go directly to Section 1 3 Converting to an ext3 File System 2 Chapter 1 The ext3 File System 1 2 Creating an ext3 File System After installation it is sometimes necessary to create a new ext3 file system For example if you add a new disk drive to the system you may want to partition the drive and use the ext3 file system
293. nd per application profiles for the kernel and kernel modules If separate library is used the sample file name includes the name of the executable as well as the name of the library 304 Chapter 43 OProfile 43 3 Starting and Stopping OProfile To start monitoring the system with OProfile execute the following command as root opcontrol start Output similar to the following is displayed Using log file var lib oprofile oprofiled log Daemon started Profiler running The settings in root oprofile daemonrc are used The OProfile daemon oprofiled is started it periodically writes the sample data to the var lib oprofile samples directory The log file for the daemon is located at var lib oprofile oprofiled log If OProfile is restarted with different configuration options the sample files for the previous session are automatically backed up in the directory var 1lib oprofile samples session N where N is the number of the previously backed up session plus 1 Backing up samples file to directory var lib oprofile samples session 1 Using log file var lib oprofile oprofiled log Daemon started Profiler running To stop the profiler executing the following command as root opcontrol shutdown 43 4 Saving Data Sometimes it is useful to save samples at a specific time For example when profiling an executable it may be useful to gather different samples based on different input data sets If the numbe
294. nd whether they are started on or stopped off in runlevels 0 6 At the end of the list is a section for the services managed by xinetd If the chkconfig list command is used to query a service managed by xinetd it displays whether the xinetd service is enabled on or disabled off For example the command chkconfig list finger returns the following output finger on As shown finger is enabled as an xinetd service If xinetd is running finger is enabled If you use chkconfig list to query a service in etc rc d service s settings for each runlevel are displayed For example the command chkconfig list httpd returns the following output httpd O off l off 2 on 3 0n 4 on 5 on 6 o0ff chkconfig can also be used to configure a service to be started or not in a specific runlevel For example to turn nscd off in runlevels 3 4 and 5 use the following command chkconfig level 345 nscd off A waming Services managed by xineta are immediately affected by chkconfig For example if xinetd is running finger is disabled and the command chkconfig finger on is executed finger is im mediately enabled without having to restart xineta manually Changes for other services do not take effect immediately after using chkconfig You must stop or start the individual service with the command service daemon stop In the previous example replace daemon with the name of the service you want to stop for example httpd Replace stop with
295. nded size 5 removing 6 syslogd 273 system analysis OProfile See OProfile system information file systems 296 dev shm 296 gathering 293 hardware 297 memory usage 295 processes 293 currently running 293 system recovery 79 common problems 79 forgetting the root password 79 hardware software problems 79 unable to boot into Red Hat Enterprise Linux 79 328 T TCP wrappers 152 telinit 152 telnet 157 tftp 91 94 97 time configuration 231 synchronize with NTP server 231 time zone configuration 232 timetool See Time and Date Properties Tool token ring connection See network configuration top 293 tune2fs converting to ext3 with 2 reverting to ext2 with 2 U updfstab 29 USB devices 28 user configuration adding users 239 adding users to groups 241 additional information 246 changing full name 241 changing home directory 241 changing login shell 241 changing password 241 command line configuration 242 passwd 242 useradd 242 filtering list of users 239 locking user accounts 241 modify groups for a user 240 modifying users 240 password forcing expiration of 243 password expiration 241 setting user account expiration 241 viewing list of users 239 User Manager See user configuration useradd command user account creation using 242 users See user configuration UUID 27 V VeriSign using existing certificate 206 video card settings for X 237 volume group
296. network but outside the enclosed subnet declarations are considered global parameters The name of the shared network should be a descriptive title for the network such as test lab to describe all the subnets in a test lab environment shared network name option domain name test redhat com option domain name servers nsl redhat com ns2 redhat com option routers 192 168 1 254 more parameters for EXAMPLE shared network subnet 192 168 1 0 netmask 255 255 255 0 parameters for subnet range 192 168 1 1 192 168 1 31 Chapter 25 Dynamic Host Configuration Protocol DHCP 183 subnet 192 168 1 32 netmask 255 255 255 0 parameters for subnet range 192 168 1 33 192 168 1 63 Example 25 2 Shared network Declaration As demonstrated in Example 25 3 the group declaration can be used to apply global parameters to a group of declarations For example shared networks subnets hosts or other groups can be grouped group option routers 192 168 1 254 option subnet mask 255 259 255 0 option domain name example com option domain name servers 192 2168 dele option time offset 18000 Eastern Standard Time host apex option host name apex example com hardware ethernet 00 A0 78 8E 9E AA fixed address 192 168 1 4 host raleigh option host name raleigh example com hardware ethernet 00 A1 DD 74 C3 F2 fixed address 192 168 1 6 Example 25 3 Group Declaration To configure a DHCP server that leases
297. nfigure The parted prompt is displayed Type he 1p to view a list of available commands If you want to create remove or resize a partition the device can not be in use partitions can not be mounted and swap space can not be enabled The partition table should not be modified while in use because the kernel may not properly recognize the changes Data could be overwritten by writing to the wrong partition because the partition table and partitions mounted do not match The easiest way to achieve this it to boot your system in rescue mode Refer to Chapter 11 Basic System Recovery for instructions on booting into rescue mode When prompted to mount the file system select Skip Alternately if the drive does not contain any partitions in use you can unmount them with the umount command and turn off all the swap space on the hard drive with the swapoff command Table 5 1 contains a list of commonly used part ed commands The sections that follow explain some of them in more detail Perform a simple check of the file system cp from to Copy file system from one partition to another fromand to are the minor numbers of the partitions Display list of available commands Create a disk label for the partition table mkfs minor num file system type Create a file system of type file system type mkpart part type fs type start mb Make a partition without creating a new file end mb system mkpartfs part type fs type start mb Make a partition
298. ng Existing Printers for details You can also configure options such as paper size if you edit the print queue after adding it 258 Chapter 36 Printer Configuration 36 8 Printing a Test Page After you have configured your printer you should print a test page to make sure the printer is func tioning properly To print a test page select the printer that you want to try out from the printer list then select the appropriate test page from the Test pulldown menu If you change the print driver or modify the driver options you should print a test page to test the different configuration Action Help B CUPS test page New QUS Letter PostScript test page Queue nam A4 PostScript test page Q ASCII text test page A Japanese EUC text test page amp Japanese JIS text test page Japanese SJIS text test page amp Japanese EUC PostScript test page Japanese JIS PostScript test page amp Japanese SJIS PostScript test page amp Duplex test Q JPEG test Figure 36 11 Test Page Options 36 9 Modifying Existing Printers To delete an existing printer select the printer and click the Delete button on the toolbar The printer is removed from the printer list Click Apply to save the changes and restart the printer daemon To set the default printer select the printer from the printer list and click the Default button on the toolbar The default printer icon y appears in the Default column of the default printer in the
299. ng the following step by step instructions On the Disk Partitioning Setup screen select Manually partition with Disk Druid 2 In Disk Druid choose New to create a new partition 3 Choose software RAID from the File System Type pulldown menu as shown in Figure 12 1 Add Partition Mount Point Not Applicable v File System Type software RAID hda 19469 MB Maxtor 52049H3 Allowable Drives hdb 19469 MB Maxtor 52049H3 Size MB 3000 Additional Size Options Eixed size O Fill all space up to MB O Fill to maximum allowable size Force to be a primary partition 2 Cancel 2 OK Figure 12 1 Creating a New RAID Partition 4 You will not be able to enter a mount point you will be able to do that once you have created your RAID device 5 A software RAID partition must be constrained to one drive For Allowable Drives select the drive on which RAID will be created If you have multiple drives all drives will be selected and you must deselect all but one drive a Enter the size that you want the partition to be x Select Fixed size to make the partition the specified size select Fill all space up to MB and enter a size in MBs to give range for the partition size or select Fill to maximum allowable size to make it grow to fill all available space on the hard disk If you make more than one partition growable they will share the available free spa
300. nguin example net at the mount point misc myproject on your machine add the following line to auto master misc etc auto misc timeout 60 Add the following line to etc auto misc myproject rw soft intr rsize 8192 wsize 8192 penguin example net proj52 The first field in etc auto misc is the name of the misc subdirectory This directory is created dynamically by automount It should not actually exist on the client machine The second field con tains mount options such as rw for read and write access The third field is the location of the NFS export including the hostname and directory Note The directory misc must exist on the local file system There should be no subdirectories in misc on the local file system Autofs is a service To start the service at a shell prompt type the following commands sbin service autofs restart To view the active mount points type the following command at a shell prompt sbin service autofs status If you modify the etc auto master configuration file while autofs is running you must tell the automount daemon s to reload by typing the following command at a shell prompt sbin service autofs reload To learn how to configure autofs to start at boot time refer to Chapter 21 Controlling Access to Services for information on managing services Chapter 23 Network File System NFS 165 23 2 3 Using TCP The default transport protocol for NFS is UDP however the Red Hat Enter
301. nnection 130 19 7 Establishing a CIPE Connection 131 19 8 Establishing a Wireless Connection 133 19 9 Managing DNS Settings 0 0 0 ec isisi OiR iiA AA ARS 135 19 10 Managing Hosts anionen iii iE AE EE E R e 136 19 11 Activating Devices 19 12 Working with Profiles s cc ecccccssssasssessisisetesejeveeseserssanrssnessiavscssaassaesvearavtniciaess 19 13 Device Aliases 00 0 eeseseeeeeeeeeeeeeee 19 14 Establishing an IPsec Connection 19 15 Saving and Restoring the Network Configuration cece 145 20 Basie Firewall Comfi guration sorsoran wee A E AENA 147 20 1 Security Level Configuration Tool 20 2 Activating the iptables Service 21 Controlling Access to Services 151 21 1 Runlevels 21 2 TCP Wrappers as 152 21 3 Services Configuration Tool 0 0 0cc ccc eect eeeeeeceeseteeetesseeeeeeeeaeaes 153 DV As MISY S Voi ei i A AEE RE EE E R E NRE 21 5 chkconfig 21 6 Additional Resources onni enn EE a aaen ENEE T ENES 155 22 OpenSSH oira n AT T E I AN 157 22 1 Why Use OpenSSH 0 0 157 22 2 Configuring an OpenSSH Server 22 3 Configuring an OpenSSH Client 22 4 Additional Resources 4 162 23 Network File System NFS 163 23 13 Why USE NES iiien n re EN EEEO ENEE E EENAA 163 23 2 Mounting NES File Systems i scsssssievscsscsyssesstosssssesesSessqautasecdvasesstastaadegveseoodeys 163
302. ns an image section with the same version as the kerne1 package just installed if the kernel smp or kernel hugemem package was installed a section will exist for it as well Notice that the default is not set to the new kernel To configure LILO to boot the new kernel by default set the default variable to the value of the label in the image section for the new kernel Run the sbin 1ilo command as root to enable the changes After running it the output will be similar to the following Added 2 4 21 1 1931 2 399 ent Added linux The after 2 4 21 1 1931 2 399 ent means the kernel in that section is the default kernel that LILO will boot Begin testing the new kernel by rebooting the computer and watching the messages to ensure the hardware is detected properly 282 Chapter 39 Upgrading the Kernel 39 6 2 Itanium Systems Itanium systems use ELILO as the boot loader which uses boot efi EFI redhat elilo conf as the configuration file Confirm that this file contains an image section with the same version as the kernel package just installed prompt timeout 50 default old image vmlinuz 2 4 21 1 1931 2 399 ent label linux initrd initrd 2 4 21 1 1931 2 399 ent img read only append root LABEL image vmlinuz 2 4 20 2 30 ent label old initrd initrd 2 4 20 2 30 ent img read only append root LABEL Notice that the default is not set to the new kernel To configure ELILO to boot the new kernel change the value of the d
303. ntal Sync Hz Vertical Sync kHz Figure 10 13 X Configuration Monitor Chapter 10 Kickstart Configurator Probe for monitor is selected by default Accept this default to have the installation program probe for the monitor during installation Probing works for most modern monitors If this option is selected and the installation program cannot successfully probe the monitor the installation program will stop at the monitor configuration screen To continue the installation process select your monitor from the list and click Next Alternatively you can select your monitor from the list You can also specify the horizontal and vertical sync rates instead of selecting a specific monitor by checking the Specify hysnc and vsync instead of monitor option This option is useful if the monitor for the system is not listed Notice that when this option is enabled the monitor list is disabled 10 9 Package Selection File Help Package Selection Select packages to install Basic Configuration Installation Method Boot Loader Options Partition Information Ignore Dependencies Network Configuration Authentication Firewall Configuration X Window System 1x Configuration GNOME Desktop Environment ac KDE Desktop Environment Pre Installation Script Dp Post tnstallation Script Editors Engineering and Scientific Graphical Internet Text based Interne
304. o The first line that begins with auth should be after any other auth sufficient lines and the line that begins with session should be after any other session optional lines If an application configured to use pam_timestamp is successfully authenticated from the Main Menu Button on the Panel the Qi icon is displayed in the notification area of the panel if you are running the GNOME or KDE desktop environment After the authentication expires the default is five minutes the icon disappears The user can select to forget the cached authentication by clicking on the icon and selecting the option to forget authentication 30 7 The floppy Group If for whatever reason console access is not appropriate for you and you need to give non root users access to your system s diskette drive this can be done using the floppy group Add the user s to the floppy group using the tool of your choice For example the gpasswd command can be used to add user fred to the floppy group gpasswd a fred floppy Now user fred is able to access the system s diskette drive from the console redhat Chapter 31 Date and Time Configuration The Time and Date Properties Tool allows the user to change the system date and time to con figure the time zone used by the system and to setup the Network Time Protocol NTP daemon to synchronize the system clock with a time server You must be running the X Window System and have root privileges to u
305. o obtain its networking configuration use the following line in the kickstart file network bootproto bootp The static method requires that you enter all the required networking information in the kickstart file As the name implies this information is static and will be used during and after the installation The line for static networking is more complex as you must include all network configuration information on one line You must specify the IP address netmask gateway and nameserver For example the indicates that it is all one line network bootproto static ip 10 0 2 15 netmask 255 255 255 0 gateway 10 0 2 254 nameserver 10 0 2 1 If you use the static method be aware of the following two restrictions All static networking configuration information must be specified on one line you cannot wrap lines using a backslash for example You can only specify one nameserver here However you can use the kickstart file s Spost section described in Section 9 7 Post installation Script to add more name servers if needed device Used to select a specific Ethernet device for installation Note that using device will not be effective unless the kickstart file is a local file such as ks f1oppy since the installation program will configure the network to find the kickstart file For example network bootproto dhcp device eth0 S ip IP address for the machine to be installed gateway Defa
306. o rename the dhcpd leases backup file to dhcpd leases and then start the daemon 25 2 3 Starting and Stopping the Server EB wnportant When the DHCP server is started for the first time it will fail unless the dhcpd leases file exists Use the command touch var lib dhcp dhcpd leases to create the file if it does not exist Chapter 25 Dynamic Host Configuration Protocol DHCP 185 To start the DHCP service use the command sbin service dhcpd start To stop the DHCP server use the command sbin service dhcpd stop To configure the daemon to start automat ically at boot time refer to Chapter 21 Controlling Access to Services for information on how to manage services If more than one network interface is attached to the system but the DHCP server should only be started on one of the interface configure the DHCP server to start only on that device In etc sysconfig dhcpd add the name of the interface to the list of DHCPDARGS Command line options here DHCPDARGS eth0O This is useful for a firewall machine with two network cards One network card can be configured as a DHCP client to retrieve an IP address to the Internet The other network card can be used as a DHCP server for the internal network behind the firewall Specifying only the network card connected to the internal network makes the system more secure because users can not connect to the daemon via the Internet Other command line options that can be specified in
307. o troubleshoot a problem with the system such as trying to load a kernel driver or when looking for unauthorized log in attempts to the system This chapter discusses where to find log files how to view log files and what to look for in log files Some log files are controlled by a daemon called syslogd A list of log messages maintained by syslogd can be found in the etc syslog conf configuration file 38 1 Locating Log Files Most log files are located in the var 1log directory Some applications such as httpd and samba have a directory within var 1og for their log files Notice the multiple files in the log file directory with numbers after them These are created when the log files are rotated Log files are rotated so their file sizes do not become too large The logrotate package contains a cron task that automatically rotates log files according to the etc logrotate conf configuration file and the configuration files in the etc logrotate d directory By default it is configured to rotate every week and keep four weeks worth of previous log files 38 2 Viewing Log Files Most log files are in plain text format You can view them with any text editor such as vi or Emacs Some log files are readable by all users on the system however root privileges are required to read most log files To view system log files in an interactive real time application use the Log Viewer To start the application go to the Main Menu Button on
308. of DHCP and BOOTP requests from a subnet with no DHCP server on it to one or more DHCP servers on other subnets When a DHCP client requests information the DHCP Relay Agent forwards the request to the list of DHCP servers specified when the DHCP Relay Agent is started When a DHCP server returns a reply the reply is broadcast or unicast on the network that sent the original request The DHCP Relay Agent listens for DHCP requests on all interfaces unless the interfaces are specified in etc sysconfig dhcrelay with the INTERFACES directive To start the DHCP Relay Agent use the command service dhcrelay start 186 Chapter 25 Dynamic Host Configuration Protocol DHCP 25 3 Configuring a DHCP Client The first step for configuring a DHCP client is to make sure the kernel recognizes the network interface card Most cards are recognized during the installation process and the system is configured to use the correct kernel module for the card If a card is added after installation Kudzu should recognize it and prompt for the configuration of the corresponding kernel module for it Be sure to check the Hardware Compatibility List available at http hardware redhat com hcl If the network card is not configured by the installation program or Kudzu and you know which kernel module to load for it refer to Chapter 40 Kernel Modules for details on loading kernel modules To configure a DHCP client manually modify the etc sysconfig network file
309. of a system s video card 01 00 0 VGA compatible controller Matrox Graphics Inc MGA G400 AGP rev 04 prog if 00 VGA Subsystem Matrox Graphics Inc Millennium G400 Dual Head Max Flags medium devsel IRQ 16 Memory at 4000000 32 bit prefetchable size 32M Memory at fcffc000 32 bit non prefetchable size 16K Memory at fc000000 32 bit non prefetchable size 8M 298 Chapter 42 Gathering System Information Expansion ROM at 80000000 disabled size 64K Capabilities dc Power Management version 2 Capabilities f0 AGP version 2 0 The lspci is also useful to determine the network card in your system if you do not know the manu facturer or model number 42 5 Additional Resources To learn more about gathering system information refer to the following resources 42 5 1 Installed Documentation ps help Displays a list of options that can be used with ps top manual page Type man top to learn more about top and its many options e free manual page type man free to learn more about free and its many options df manual page Type man df to learn more about the df command and its many options du manual page Type man du to learn more about the du command and its many options lspci manual page Type man lspci to learn more about the 1spci command and its many options proc directory The contents of the proc directory can also be used to gather more de tailed s
310. oftware RAID Level 1 RAID level 1 or mirroring has been used longer than any other form of RAID Level 1 provides redundancy by writing identical data to each member disk of the array leaving a mirrored copy on each disk Mirroring remains popular due to its simplicity and high level of data availability Level 1 operates with two or more disks that may use parallel access for high data transfer rates when reading but more commonly operate independently to provide high I O transaction rates Level 1 provides very good data reliability and improves performance for read intensive applications but at a relatively high cost 7 The storage capacity of the level 1 array is equal to the capacity of one of the mirrored hard disks in a Hardware RAID or one of the mirrored partitions in a Software RAID 1 A hot swap chassis allows you to remove a hard drive without having to power down your system 2 RAID level 1 comes at a high cost because you write the same information to all of the disks in the array which wastes drive space For example if you have RAID level 1 set up so that your root partition exists on two 40G drives you have 80G total but are only able to access 40G of that 80G The other 40G acts like a mirror of the first 40G Chapter 3 Redundant Array of Independent Disks RAID 11 Level 4 Level 4 uses parity concentrated on a single disk drive to protect data It is better suited to transaction I O rather than lar
311. ollowing types of authentication ADS The Samba server acts as a domain member in an Active Directory Domain ADS realm For this option Kerberos must be installed and configured on the server and Samba must become a member of the ADS realm using the net utility which is part of the samba client package Refer to the net man page for details This option does not configure Samba to be an ADS Controller Chapter 24 Samba 173 Domain The Samba server relies on a Windows NT Primary or Backup Domain Controller to verify the user The server passes the username and password to the Controller and waits for it to return Specify the NetBIOS name of the Primary or Backup Domain Controller in the Authentication Server field The Encrypted Passwords option must be set to Yes if this is selected Server The Samba server tries to verify the username and password combination by passing them to another Samba server If it can not the server tries to verify using the user authentication mode Specify the NetBIOS name of the other Samba server in the Authentication Server field Share Samba users do not have to enter a username and password combination on a per Samba server basis They are not prompted for a username and password until they try to connect to a specific shared directory from a Samba server User Default Samba users must provide a valid username and password on a per Samba server basis Select this option i
312. ollowing sections 6 1 1 Enabling Quotas As root using a text editor edit the etc fstab file and add the usrquota and or grpquota options to the file systems that require quotas LABEL ext3 defaults 11 LABEL boot boot ext3 defaults 12 none dev pts devpts gid 5 mode 620 0 0 LABEL home home ext3 defaults usrquota grpquota 1 2 none proc proc defaults 00 none dev shm tmpfs defaults 00 dev hda2 swap swap defaults 00 dev cdrom mnt cdrom udf iso9660 noauto owner kudzu ro 0 0 dev d0 mnt floppy auto noauto owner kudzu 0 0 In this example the home file system has both user and group quotas enabled 6 1 2 Remounting the File Systems After adding the userquota and grpquota options remount each file system whose fstab entry has been modified If the file system is not in use by any process use the umount command followed by the mount to remount the file system If the file system is currently in use the easiest method for remounting the file system is to reboot the system 22 Chapter 6 Implementing Disk Quotas 6 1 3 Creating Quota Files After each quota enabled file system is remounted the system is capable of working with disk quo tas However the file system itself is not yet ready to support quotas The next step is to run the quotacheck command The quotacheck command examines quota enabled file systems and builds a table of the current disk usage per file system The table is then used to update the
313. ols you are enhancing the security of your machine All communications using OpenSSH tools including passwords are encrypted Telnet and ftp use plain text passwords and send all information unencrypted The information can be intercepted the passwords can be retrieved and then your system can be compromised by an unauthorized person logging in to your system using one of the intercepted passwords The OpenSSH set of utilities should be used whenever possible to avoid these security problems Another reason to use OpenSSH is that it automatically forwards the DISPLAY variable to the client machine In other words if you are running the X Window System on your local machine and you log in to a remote machine using the ssh command when you run a program on the remote machine that requires X it will be displayed on your local machine This feature is convenient if you prefer graphical system administration tools but do not always have physical access to your server 22 2 Configuring an OpenSSH Server To run an OpenSSH server you must first make sure that you have the proper RPM packages installed The openssh server package is required and depends on the openssh package The OpenSSH daemon uses the configuration file etc ssh sshd_config The default configu ration file should be sufficient for most purposes If you want to configure the daemon in ways not provided by the default sshd_config read the sshd man page for a list of the keywords t
314. om that hard drive To boot into rescue mode you must be able to boot the system using one of the following methods By booting the system from an installation boot diskette By booting the system from an installation boot CD ROM By booting the system from the Red Hat Enterprise Linux CD ROM 1 Once you have booted using one of the described methods add the keyword rescue as a kernel pa rameter For example for an x86 system type the following command at the installation boot prompt linux rescue You are prompted to answer a few basic questions including which language to use It also prompts you to select where a valid rescue image is located Select from Local CD ROM Hard Drive NFS image FTP or HTTP The location selected must contain a valid installation tree and the installation tree must be for the same version of Red Hat Enterprise Linux as the Red Hat Enterprise Linux CD ROM 1 from which you booted If you used a boot CD ROM or diskette to start rescue mode the installation tree must be from the same tree from which the media was created For more information about how to setup an installation tree on a hard drive NFS server FTP server or HTTP server refer to the Red Hat Enterprise Linux Installation Guide If you select a rescue image that does not require a network connect you are asked whether or not you want to establish a network connection A network connection is useful if you need to backup files to
315. ommand line version can be used in a configuration script or a kickstart script The authentication options are summarized in Table 29 1 Option Description O disableldap ldapbasedn lt dn gt Chapter 29 Authentication Configuration 223 Option Description i O services even if they are configured Table 29 1 Command Line Options Specify Hesiod RHS om These options can also be found in the authconfig man page or by typing authconfig help ata shell prompt 224 Chapter 29 Authentication Configuration V System Configuration Part of a system administrator s job is configuring the system for various tasks types of users and hardware configurations This section explains how to configure a Red Hat Enterprise Linux system Table of Contents 30 31 32 33 34 35 36 37 38 39 40 41 Console ACCESS s ssssscssssssssesscssssssssssccssesssnsesssssssssesessessssssssasesssssessesesssssesesseseseseseasesssessesesesees Date and Time Configuration ssssssscssssssssssccsssssssssssssssssssesessssessesessssssssssesesesessasereseses Keyboard Configuration sssssssccssssssccssssssssssessesssessssssessssssssesssssesessevesesesssessesesessseeseseees Mouse Configuration ccccsssssssssscrsssssssessssssssssssvesssesssssessesssssessssssessssesesesesssessesesesseseseseees X Window System Configuration User and Group Configuration sssssssssssssssscsssssssscscse
316. ompt After changing any of the options they can be saved by clicking the Save and quit button The prefer ences are written to root oprofile daemonrc and the application exits Exiting the application does not stop OProfile from sampling On the Setup tab to set events for the processor counters as discussed in Section 43 2 2 Setting Events to Monitor select the counter from the pulldown menu and select the event from the list A brief description of the event appears in the text box below the list Only events available for the specific counter and the specific architecture are displayed The interface also displays whether or not the profiler is running and some brief statistics about it Setup Configuration Counter 0 BUS_DRDY_CLOCKS w Counter settings Z Enabled Event a Profile kemel L2_DBUS_BUSY Z Profile user binaries L2_DBUS_BUSY_RD f BUS_DRDY_CLOCKS Count 397952 BUS_LOCK_CLOCKS Unit mask US REC CUTS TANDING self generated transactions BUS_TRAN_BRD es BUS_TRAN_RFO v any transactions BUS_TRANS_WB BUS_TRAN_IFETCH BUS_TRAN_INVAL BUS_TRAN_PWR BUS_TRANS_P BUS_TRANS_IO BUS_TRANS_DEF BUS_TRAN_BURST BUS_TRAN_ANY BUS_TRAN_MEM BUS_DATA_RCV BUS_BNR_DRV BUS_HIT_DRV BUS_HITM_DRV BUS_SNOOP_STALL COMP_FLOP_RET FLOPS iCYCLES_DIV_BUSY LD_BLOCKS SB_DRAINS MISALIGN_MEM_REF EMON_KNI_PREF_DISPATCHED EMON KNI PRFF MISS Ka
317. on sshd pam_unix 17633 session opened for user tfox by uid May 15 14 38 29 falcon kernel Creative EMU10K1 PCI Audio Driver version 0 20 13 May 15 14 38 29 falcon kermel emu10k1 EMU10K1 rev 7 model 0x8022 found IO at May 15 14 38 29 falcon kernel ac97_codec AC97 Audio codec id CRY20 Cirrus Lc May 15 14 38 30 falcon modprobe modprobe Can t locate module sound service 0 0 May 15 15 00 38 falcon sshd pam_unix 17633 session closed for user tfox May 15 15 06 24 falcon userhelper pam_timestamp timestamp file var run sudo tfo May 15 15 06 29 falcon su pam_unix 17893 session opened for user root by tfox uir gt Filter for ig Filter G Reset Figure 38 1 Log Viewer Chapter 38 Log Files By default the currently viewable log file is refreshed every 30 seconds To change the refresh rate select Edit gt Preferences from the pulldown menu The window shown in Figure 38 2 will appear In the Log Files tab click the up and down arrows beside the refresh rate to change it Click Close to return to the main window The refresh rate is changed immediately To refresh the currently viewable file manually select File gt Refresh Now or press Ctrl R On the Log Files tab in the Preferences the log file locations can be modified Select the log file from the list and click the Edit button Type the new location of the log file or click t
318. oolbar 3 Select Token Ring connection from the Device Type list and click Forward 4 If you have already added the token ring card to the hardware list select it from the Tokenring card list Otherwise select Other Tokenring Card to add the hardware device 5 If you selected Other Tokenring Card the Select Token Ring Adapter window as shown in Figure 19 10 appears Select the manufacturer and model of the adapter Select the device name If this is the system s first token ring card select tr0 if this is the second token ring card select tr1 and so on The Network Administration Tool also allows the user to configure the resources for the adapter Click Forward to continue Chapter 19 Network Configuration Select Token Ring Adapter Adapter IBM Olympic based PCI token ring Device trO Resource IRQ Unknown Cancel D Eorward Figure 19 10 Token Ring Settings 131 6 On the Configure Network Settings page choose between DHCP and static IP address You may specify a hostname for the device If the device receives a dynamic IP address each time the network is started do not specify a hostname Click Forward to continue 7 Click Apply on the Create Tokenring Device page After configuring the token ring device it appears in the device list as shown in Figure 19 11 File Profile Help B B 4 ax New Edit Copy Delete Activate Deac
319. oot In most cases it should be left to the default value The Core Dump Directory value corresponds to the CoreDumpDirectory directive The Apache HTTP Server tries to switch to this directory before dumping core The default value is the ServerRoot However if the user that the server runs as can not write to this directory the core dump can not be written Change this value to a directory writable by the user the server runs as if you want to write the core dumps to disk for debugging purposes 200 Chapter 26 Apache HTTP Server Configuration The User value corresponds to the User directive It sets the userid used by the server to answer requests This user s settings determine the server s access Any files inaccessible to this user will also be inaccessible to your website s visitors The default for User is apache The user should only have privileges so that it can access files which are supposed to be visible to the outside world The user is also the owner of any CGI processes spawned by the server The user should not be allowed to execute any code which is not intended to be in response to HTTP requests A waming Unless you know exactly what you are doing do not set the user directive to root Using root as the User will create large security holes for your Web server The parent httpd process first runs as root during normal operations but is then immediately handed off to the apache user The server must start as root
320. ooted into Red Hat Enterprise Linux without a working boot diskette To create the boot diskette login as root and type the following command at a shell prompt sbin mkbootdisk uname r Refer to the man page for mkboot disk for more options Reboot the machine with the boot diskette and verify that it works before continuing Hopefully the diskette will not be needed but store it in a safe place just in case To determine which kernel packages are installed execute the following command at a shell prompt rpm qa grep kernel The output contains some or all of the following packages depending on the system s architecture the version numbers and packages may differ kernel 2 4 21 1 1931 2 399 ent kernel source 2 4 21 1 1931 2 399 ent kernel utils 2 4 21 1 1931 2 399 ent kernel pcemcia cs 3 1 31 13 kernel smp 2 4 21 1 1931 2 399 ent From the output determine which packages need to be download for the kernel upgrade For a single processor system the only required package is the kernel package Refer to Section 39 1 Overview of Kernel Packages for descriptions of the different packages In the filename each kernel package contains the architecture for which the package was built The format is kernel lt variant gt lt version gt lt arch gt rpm where lt variant gt is smp utils etc The lt arch gt is one of the following 1 x86_64 for the AMD64 architecture Chapter 39 Upgrading the Kernel 279
321. oper s project page redhat Chapter 8 Access Control Lists Files and directories have permission sets for the owner of the file the group associated with the file and all other users for the system However these permission sets have limitations For example different permissions can not be configured for different users Thus Access Control Lists ACLs were implemented The Red Hat Enterprise Linux 3 kernel provides ACL support for the ext3 file system and NFS exported file systems ACLs are also recognized on ext3 file systems accessed via Samba Along with support in the kernel the acl package is required to implement ACLs It contains the utilities used to add modify remove and retrieve ACL information The cp and mv commands copy or move any ACLs associated with files and directories 8 1 Mounting File Systems Before using ACLs for a file or directory the partition for the file or directory must be mounted with ACL support If it is a local ext3 file system it can mounted with the following command mount t ext3 o acl lt device name gt lt partition gt For example mount t ext3 o acl dev hdb3 work Alternatively if the partition is listed in the etc fstab file the entry for the partition can include the acl option LABEL work work ext3 acl 1 42 If an ext3 file system is accessed via Samba and ACLs have been enabled for it the ACLs are rec ognized because Samba has been compiled with the
322. operating system s copy of disk usage In addition the file system s disk quota files are updated To create the quota files aquota user and aquota group on the file system use the c option of the quotacheck command For example if user and group quotas are enabled for the home partition create the files in the home directory quotacheck acug home The a option means that all mounted non NFS file systems in etc mtab are checked to see if quotas are enabled The c option specifies that the quota files should be created for each file system with quotas enabled the u specifies to check for user quotas and the g option specifies to check for group quotas If neither the u or g options are specified only the user quota file is created If only g is specified only the group quota file is created After the files are created run the following command to generate the table of current disk usage per file system with quotas enabled quotacheck avug The options used are as follows e a Check all quota enabled locally mounted file systems e v Display verbose status information as the quota check proceeds e u Check user disk quota information e g Check group disk quota information After quotacheck has finished running the quota files corresponding to the enabled quotas user and or group are populated with data for each quota enabled file system such as home 6 1 4 Assigning Quotas per User The l
323. or kernel If 0 samples are not collected for this counter event when the processor is in kernel space if 1 samples are collected even if the processor is in kernel space unit_mask Which unit masks are enabled for the counter user If0 samples are not collected for the counter event when the processor is in user space if 1 samples are collected even if the processor is in user space The values of these files can be retrieved with the cat command For example cat dev oprofile 0 count 43 7 Example Usage While OProfile can be used by developers to analyze application performance it can also be used by system administrators to perform system analysis For example Determine which applications and services are used the most on a system op_t ime can be used to determine how much processor time an application or service uses If the system is used for multiple services but is under performing the services consuming the most processor time can be moved to dedicated systems 310 Chapter 43 OProfile Determine processor usage The CPU_CLK_UNHALTED event can be monitored to determine the processor load over a given period of time This data can then be used to determine if additional processors or a faster processor might improve system performance 43 8 Graphical Interface Some OProfile preferences can be set with a graphical interface To start it execute the oprof_start command as root at a shell pr
324. or print jobs The default port is 9100 Next select the printer type Refer to Section 36 7 Selecting the Printer Model and Finishing for details 36 7 Selecting the Printer Model and Finishing After selecting the queue type of the printer the next step is to select the printer model You will see a window similar to Figure 36 10 If it was not auto detected select the model from the list The printers are divided by manufacturers Select the name of the printer manufacturer from the pulldown menu The printer models are updated each time a different manufacturer is selected Select the printer model from the list Chapter 36 Printer Configuration 257 Printer model Select the printer manufacturer and model Notes HP X z 2500C 2500CM 2563 b lt is Help Cancel lt 4 Back D Forward Figure 36 10 Selecting a Printer Model The recommended print driver is selected based on the printer model selected The print driver pro cesses the data that you want to print into a format the printer can understand Since a local printer is attached directly to your computer you need a print driver to process the data that is sent to the printer If you are configuring a remote printer IPP LPD SMB or NCP the remote print server usually has its own print driver If you select an additional print driver on your local computer the data is filtered
325. ore information on checking a package s signature Note If you are installing a kernel package you should use rpm ivh instead Refer to Chapter 39 Up grading the Kernel for details Installing packages is designed to be simple but you may sometimes see errors 16 2 2 1 Package Already Installed If the package of the same version is already installed the following is displayed Preparing HAART ART HRA AE AE AE AE AE AE AE AE HEA EHH E 1005 package foo 1 0 1 is already installed To install the package anyway and the same version you are trying to install is already installed you can use the replacepkgs option which tells RPM to ignore the error rpm ivh replacepkgs foo 1 0 1 i386 rpm This option is helpful if files installed from the RPM were deleted or if you want the original config uration files from the RPM to be installed 16 2 2 2 Conflicting Files If you attempt to install a package that contains a file which has already been installed by another package or an earlier version of the same package the following is displayed Preparing AEAEE EAE AE AE AE AE AE AE AE AE AE AE AE AE AE AE AE AE AE AE AE AE AE AE AEAEE E EE 1005 file usr bin foo from install of foo 1 0 1 conflicts with file from package bar 2 0 20 To make RPM ignore this error use the replacefiles option rpm ivh replacefiles foo 1 0 1 i386 rpm 106 Chapter 16 Package Management with RPM 16 2 2 3 Unresolved Dependency
326. ored because each time the printer daemon is restarted it creates a new etc printcap file from the Printer Configuration Tool configuration file When creating a backup of the system s configuration files use the following method to save the printer configuration files To save your printer configuration type this command as root usr sbin redhat config printer tui Xexport gt settings xml Your configuration is saved to the file sett ings xml If this file is saved it can be used to restore the printer settings This is useful if the printer configura tion is deleted if Red Hat Enterprise Linux is reinstalled or if the same printer configuration is needed on multiple systems The file should be saved on a different system before reinstalling To restore the configuration type this command as root usr sbin redhat config printer tui Ximport lt settings xml If you already have a configuration file you have configured one or more printers on the system already and you try to import another configuration file the existing configuration file will be over written If you want to keep your existing configuration and add the configuration in the saved file you can merge the files with the following command as root usr sbin redhat config printer tui Ximport merge lt settings xml Your printer list will then consist of the printers you configured on the system as well as the printers you imported from the saved configura
327. ork for more details on Red Hat Network 16 2 2 Installing RPM packages typically have file names like foo 1 0 1 i386 rpm The file name includes the package name foo version 1 0 release 1 and architecture i386 Installing a package is as simple as logging in as root and typing the following command at a shell prompt rpm Uvh foo 1 0 1 1386 rpm If installation is successful the following output is displayed Preparing AEE AE AEA AE AE AE AE AE AEA aE AE AE aE AEA AE AEE AEA AP aE EAE EEE aE HE aE EAE 1005 1 foo FEAE AE AE AE E AE AE AE AE AE E AE E AE E AE aE A AE AE AE AE AEE HE AEE aE EEEE EAE HEE 1003 As you can see RPM prints out the name of the package and then prints a succession of hash marks as the package is installed as a progress meter Starting with version 4 1 of RPM the signature of a package is checked automatically when installing or upgrading a package If verifying the signature fails an error message such as the following is displayed Chapter 16 Package Management with RPM 105 error V3 DSA signature BAD key ID 0352860f If it is a new header only signature an error message such as the following is displayed error Header V3 DSA signature BAD key ID 0352860f If you do not have the appropriate key installed to verify the signature the message contains the word NOKEY such as warning V3 DSA signature NOKEY key ID 0352860f Refer to Section 16 3 Checking a Package s Signature for m
328. orrectly is the correct partition type and is the correct file system type After rebooting the system into normal mode use the command df to make sure the partition was mounted and is recognized with the new size gy redhat Chapter 6 Implementing Disk Quotas Disk space can be restricted by implementing disk quotas so that the system administrator is alerted before a user consumes too much disk space or a partition becomes full Disk quotas can be configured for individual users as well as user groups This kind of flexibility makes it possible to give each user a small quota to handle personal file such as email and reports while allowing the projects they work on to have more sizable quotas assuming the projects are given their own groups In addition quotas can be set not just to control the number of disk blocks consumed but to control the number of inodes Because inodes are used to contain file related information this allows control over the number of files that can be created The quota RPM must be installed to implement disk quotas For more information on installing RPM packages refer to Part III Package Management 6 1 Configuring Disk Quotas To implement disk quotas use the following steps 1 Enable quotas per file system by modifying etc fstab 2 Remount the file system s 3 Create the quota files and generate the disk usage table 4 Assign quotas Each of these steps is discussed in detail in the f
329. ot the following script does the trick cd etc pam d for iin do sed pam_console so s lt i gt foo amp amp mv foo i done 30 4 Defining the Console The pam_console so module uses the etc security console perms file to determine the permissions for users at the system console The syntax of the file is very flexible you can edit the file so that these instructions no longer apply However the default file has a line that looks like this lt console gt tty 0 9 0 9 0 9 0 9 0 9 When users log in they are attached to some sort of named terminal either an X server with a name like 0 or mymachine example com 1 0 or a device like dev ttyS0 or dev pts 2 The de fault is to define that local virtual consoles and local X servers are considered local but if you want to consider the serial terminal next to you on port dev ttyS1 to also be local you can change that line to read lt console gt tty 0 9 0 9 0 9 0 9 0 9 dev ttyS1 30 5 Making Files Accessible From the Console In etc security console perms there is a section with lines like lt floppy gt dev fd 0 1 dev floppy mnt floppy lt sound gt dev dsp dev audio dev midi dev mixer dev sequencer Chapter 30 Console Access 229 dev sound dev beep lt cdrom gt dev cdrom dev cdroms dev cdwriter mnt cdrom You can add your own lines to this section if necessary Make sure that any line
330. owed to run programs that accomplish tasks normally restricted to the root user If X is running these actions can be included as menu items in a graphical user interface As shipped the console accessible programs include halt poweroff and reboot 30 1 Disabling Shutdown Via Ctrl Alt Del By default etc inittab specifies that your system is set to shutdown and reboot the system in response to a Ctrl Alt Del key combination used at the console To completely disable this ability comment out the following line in etc inittab by putting a hash mark in front of it ca ctrlaltdel sbin shutdown t3 r now Alternatively you may just want to allow certain non root users the right to shutdown the system from the console using Ctrl Alt Del You can restrict this privilege to certain users by taking the following steps 1 Add the a option to the etc inittab line shown above so that it reads ca ctrlaltdel sbin shutdown a t3 r now The a flag tells shutdown to look for the etc shutdown allow file 2 Create a file named shutdown allowin etc The shutdown allovw file should list the user names of any users who are allowed to shutdown the system using Ctrl Alt Del The format of the etc shutdown allow file is a list of usernames one per line like the following stephen jack sophie According to this example shut down allow file stephen jack and sophie are allowed to shut down the system from t
331. owned by user juan and group juan However it has read write and execute privileges only for the user juan All other permissions are denied 6 The files within the etc skel directory which contain default user settings are copied into the new home juan directory At this point a locked account called juan exists on the system To activate it the administrator must next assign a password to the account using the passwd command and optionally set password aging guidelines 35 7 Additional Information Refer to these resources for more information on user and group management Chapter 35 User and Group Configuration 247 35 7 1 Installed Documentation The man pages for useradd passwd groupadd and chage 35 7 2 Related Books Red Hat Enterprise Linux Reference Guide This manual gives a list of standard users and groups discusses user private groups and provides an overview of shadow passwords Red Hat Enterprise Linux Introduction to System Administration This companion manual con tains more information on managing users and groups as well as managing user resources 248 Chapter 35 User and Group Configuration redhat Chapter 36 Printer Configuration The Printer Configuration Tool allows users to configure a printer This tool helps maintain the printer configuration file print spool directories and print filters Red Hat Enterprise Linux 3 uses the CUPS printing system If a system
332. p_to_source source dir lt src dir gt lt executable gt The directory containing the source code and the executable to be analyzed must be specified Refer to the op_to_source man page for a list of additional command line options Chapter 43 OProfile 309 43 5 4 Using op_merge If multiple sample files exist for the exact same executable or library the sample files can be merged for easier analysis For example to merge files for the library usr lib library 1 2 3 so execute the following command as root op_merge usr lib library 1 2 3 so The resulting file is var lib oprofile samples usr lib library 1 2 3 s0 To limit the samples merged to a specific counter use the c option followed by the counter number 43 6 Understanding dev profile The dev oprofile directory contains the file system for OProfile Use the cat command to display the values of the virtual files in this file system For example the following command displays the type of processor OProfile detected cat dev oprofile cpu_type A directory exists in dev oprofile for each counter For example if there are 2 counters the directories dev oprofile 0 and dev oprofile 1 exist Each directory for a counter contains the following files count Interval between samples enabled If 0 the counter is off and no samples are collected for it If 1 the counter is on and samples are being collected for it event Event to monit
333. p_to_source Creates annotated source for an executable if the application was compiled with debugging symbols Refer to Section 43 5 3 Using op_to_source for details Runs as a daemon to periodically write sample data to disk oprofpp Retrieves profile data Refer to Section 43 5 2 Using oprofpp for details op_import Converts sample database files from a foreign binary format to the native format for the system Only use this option when analyzing a sample database from a different architecture Table 43 1 OProfile Commands 43 2 Configuring OProfile Before OProfile can be run it must be configured At a minimum selecting to monitor the kernel or selecting not to monitor the kernel is required The following sections describe how to use the opcontrol utility to configure OProfile As the opcont rol commands are executed the setup op tions are saved to the root oprofile daemonrc file 43 2 1 Specifying the Kernel First configure whether OProfile should monitor the kernel This is the only configuration option that is required before starting OProfile All others are optional To monitor the kernel execute the following command as root opcontrol vmlinux boot vmlinux uname r To configure OProfile not to monitor the kernel execute the following command as root opcontrol no vmlinux Chapter 43 OProfile 301 This command also loads the oprofile kernel module if it is not already loaded and creates th
334. passwd 5 Make sure the smb service is started by typing the command service smb restart ata shell prompt 6 If you want the smb service to start automatically use ntsysv chkconfig or the Services Configuration Tool to enable it at runtime Refer to Chapter 21 Controlling Access to Services for details The pam_smbpass PAM module can be used to sync users Samba passwords with their system passwords when the passwd command is used If a user invokes the passwd command the password he uses to log in to the Red Hat Enterprise Linux system as well as the password he must provide to connect to a Samba share are changed To enable this feature add the following line to etc pam d system auth below the pam_cracklib so invocation password required lib security pam_smbpass so nullok use_authtok try_first_pass 24 2 4 Starting and Stopping the Server On the server that is sharing directories via Samba the smb service must be running View the status of the Samba daemon with the following command sbin service smb status Start the daemon with the following command sbin service smb start Stop the daemon with the following command sbin service smb stop To start the smb service at boot time use the command sbin chkconfig level 345 smb on You can also use chkconfig ntsysv or the Services Configuration Tool to configure which services start at boot time Refer to Chapter 21 Controlling Access to Services for details
335. path home share valid users tfox carole public no writable yes printable no create mask 0765 The above example allows the users tfox and carole to read and write to the directory home share on the Samba server from a Samba client 24 2 3 Encrypted Passwords Encrypted passwords are enabled by default because it is more secure If encrypted passwords are not used plain text passwords are used which can be intercepted by someone using a network packet sniffer It is recommended that encrypted passwords be used The Microsoft SMB Protocol originally used plaintext passwords However Windows NT 4 0 with Service Pack 3 or higher Windows 98 Windows 2000 Windows ME and Windows XP require encrypted Samba passwords To use Samba between a Linux system and a system running one of these Windows operating systems you can either edit your Windows registry to use plaintext passwords or configure Samba on your Linux system to use encrypted passwords If you choose to modify your registry you must do so for all your Windows machines this is risky and may cause further conflicts It is recommended that you use encrypted passwords for better security To configure Samba to use encrypted passwords follow these steps 1 Create a separate password file for Samba To create one based on your existing etc passwd file at a shell prompt type the following command cat etc passwd mksmbpasswd sh gt etc samba smbpasswd If
336. pecify an authentication key or click Generate to generate one It can be any combination of numbers and letters Click Forward to continue IPsec Remote Network Please enter your remote network settings Remote IP Address 172 16 57 27 Remote Network Address 192 168 1 0 Remote Subnet Mask 255 255 255 0 Remote Network Gateway 192 1681 1 3 Cancel lt Back gt Eorward Figure 19 25 Remote Network Information 9 Verify the information on the IPsec Summary page and click Apply 10 Select File gt Save to save the configuration 11 Select the IPsec connection from the list and click the Activate button 12 As root at a shell prompt enable IP forwarding a Edit etc sysct1 conf and set net ipv4 ip_forwardto 1 b Execute the following command to enable the change sysctl p etc sysctl conf The network script to activate the IPsec connection automatically creates network routes to send pack ets through the IPsec router if necessary Refer to Section 19 14 3 Testing the IPsec Connection to determine if the IPsec connection has been successfully established Chapter 19 Network Configuration 145 19 14 3 Testing the IPsec Connection Use the tcpdump utility to view the network packets being transfered between the hosts or networks and verify that they are encrypted via IPsec The packet should include an AH header and should be shown as ESP packets ES
337. ple use of verifying is rpm V foo Chapter 16 Package Management with RPM 109 which verifies that all the files in the foo package are as they were when they were originally installed For example e To verify a package containing a particular file rpm Vf bin vi e To verify ALL installed packages rpm Va e To verify an installed package against an RPM package file rpm Vp foo 1 0 1 i1386 rpm This command can be useful if you suspect that your RPM databases are corrupt If everything verified properly there is no output If there are any discrepancies they are displayed The format of the output is a string of eight characters a c denotes a configuration file and then the file name Each of the eight characters denotes the result of a comparison of one attribute of the file to the value of that attribute recorded in the RPM database A single a period means the test passed The following characters denote failure of certain tests 5 MDS checksum e s file size L symbolic link T file modification time D device e U user G group M mode includes permissions and file type unreadable file If you see any output use your best judgment to determine if you should remove or reinstall the package or fix the problem in another way 16 3 Checking a Package s Signature If you wish to verify that a package has not been corrupted or tampered with examine only the md
338. pment and the most up to date informa tion for them is available from their websites The man pages for OpenSSH and OpenSSL tools are also good sources of detailed information 22 4 1 Installed Documentation The ssh scp sftp sshd and ssh keygen man pages These man pages include information on how to use these commands as well as all the parameters that can be used with them 22 4 2 Useful Websites http www openssh com The OpenSSH FAQ page bug reports mailing lists project goals and a more technical explanation of the security features http www openssl org The OpenSSL FAQ page mailing lists and a description of the project goal http www freessh org SSH client software for other platforms 22 4 3 Related Books Red Hat Enterprise Linux Reference Guide Learn the event sequence of an SSH connection review a list of configuration files and discover how SSH can be used for X forwarding gy redhat Chapter 23 Network File System NFS Network File System NFS is a way to share files between machines on a network as if the files were located on the client s local hard drive Red Hat Enterprise Linux can be both an NFS server and an NFS client which means that it can export file systems to other systems and mount file systems exported from other machines 23 1 Why Use NFS NFS is useful for sharing directories of files between multiple users on the same network For example a
339. print spool command line 263 Printer Configuration Tool See printer configuration printtool See printer configuration processes 293 ps 293 PXE 91 PXE installations 91 adding hosts 93 boot message custom 95 configuration 91 DHCP configuration 94 98 Network Booting Tool 91 overview 91 performing 95 setting up the network server 91 pxeboot 94 pxeos 92 326 Q quotacheck 22 quotacheck command checking quota accuracy with 24 quotaoff 25 quotaon 25 R racoon 141 143 RAID 9 configuring software RAID 83 explanation of 9 Hardware RAID 9 level 0 10 level 1 10 level 4 10 level 5 10 levels 10 reasons to use 9 Software RAID 9 RAM 295 rep 158 Red Hat Network 117 Red Hat Package Manager See RPM Red Hat RPM Guide 112 Red Hat Update Agent 117 redhat config date See Time and Date Properties Tool redhat config httpd See HTTP Configuration Tool redhat config keyboard 233 redhat config kickstart See Kickstart Configurator redhat config mouse See Mouse Configuration Tool redhat config netboot 91 redhat config network See network configuration redhat config network cmd 123 139 145 redhat config network tui See network configuration redhat config packages See Package Management Tool redhat config printer See printer configuration redhat config securitylevel See Security Level Configuration Tool redhat config time See Time and Date Prope
340. printer daemon service cups restart 36 11 2 Removing a Local Printer A printer queue can also be removed via the command line As root to remove a printer queue redhat config printer tui Xremove local options Options device node Required The device node used such as dev 1p0 make make Required The IEEE 1284 MANUFACTURER string or if none is available the printer man ufacturer s name as in the foomatic database 262 Chapter 36 Printer Configuration model mode1 Required The IEEE 1284 MODEL string or if none is available the printer model as listed in the foomatic database After removing the printer from the Printer Configuration Tool configuration restart the printer daemon for the changes to take effect service cups restart If all printers have been removed and you do not want to run the printer daemon anymore execute the following command service cups stop 36 11 3 Setting the Default Printer To set the default printer use the following command and specify the queuename redhat config printer tui Xdefault queue queuename 36 12 Managing Print Jobs When you send a print job to the printer daemon such as printing text file from Emacs or printing an image from The GIMP the print job is added to the print spool queue The print spool queue is a list of print jobs that have been sent to the printer and information about each print request such as the status of
341. prise Linux 3 kernel includes support for NFS over TCP To use NFS over TCP include the o tcp option to mount when mounting the NFS exported file system on the client system For example mount o tcp shadowman example com misc export misc local If the NFS mount is specified in etc fstab server usr local pub pub nfs rsize 8192 wsize 8192 timeo 14 intr tcp If it is specified in an autofs configuration file myproject rw soft intr rsize 8192 wsize 8192 tcp penguin example net proj52 Since the default is UDP if the o tcp option is not specified the NFS exported file system is ac cessed via UDP The advantages of using TCP include the following Improved connection durability thus less NFS stale file handles messages e Performance gain on heavily loaded networks because TCP acknowledges every packet unlike UDP which only acknowledges completion TCP has better congestion control than UDP which has none On a very congested network UDP packets are the first types of packet that are dropped Which means if NFS is writing data in 8K chunks all of that 8K has to retransmitted With TCP because of its reliability one parts of that 8K data is transmitted at a time e Error detection When a tcp connection breaks due to the server going down the client stops sending data and starts the reconnection process With UDP since its connection less the client continue to pound the network with data until server comes up Th
342. process If automatic is selected the racoon daemon is used to manage the encryption key If racoon is used the ipsec tools package must be installed Click Forward to continue 7 Specify the IP address of the other host If you do not know the IP address of the other system run the command sbin ifconfig lt device gt on the other system where lt device gt is the Ethernet device used to connect to the other host If only one Ethernet card exists in the system the device name is eth0 The IP address is the number following the inet addr label Click Forward to continue 8 If manual encryption was selected in step 6 specify the encryption key to use or click Generate to create one Specify an authentication key or click Generate to generate one It can be any combination of numbers and letters Click Forward to continue 142 Chapter 19 Network Configuration 9 Verify the information on the IPsec Summary page and click Apply 10 Select File gt Save to save the configuration 11 Select the IPsec connection from the list and click the Activate button 12 Repeat for the other host It is extremely important that the same keys from step 8 be used on the other hosts Otherwise IPsec will not work After configuring the IPsec connection it appears in the IPsec list as shown in Figure 19 22 File Profile Help B B 7 ma New Edit Copy Delete Activate Deactivate Devices Hardware IPsec D
343. ption configures the system to reject incoming connections that are not in response to outbound requests such as DNS replies or DHCP requests If access to services running on this machine is needed you can choose to allow specific services through the firewall If you are connecting your system to the Internet but do not plan to run a server this is the safest choice Selecting any of the Trusted devices allows access to your system for all traffic from that device it is excluded from the firewall rules For example if you are running a local network but are con nected to the Internet via a PPP dialup you can check eth0 and any traffic coming from your local network will be allowed Selecting eth0 as trusted means all traffic over the Ethernet is allowed but the ppp0 interface is still firewalled To restrict traffic on an interface leave it unchecked It is not recommended that you make any device that is connected to public networks such as the Internet a Trusted device Enabling options in the Trusted services list allows the specified service to pass through the fire wall WWW HTTP The HTTP protocol is used by Apache and by other Web servers to serve webpages If you plan on making your Web server publicly available enable this option This option is not required for viewing pages locally or for developing webpages You must have the httpd package installed to serve webpages Enabling WWW HTTP will not open a port for
344. ption keyword and are referred to as options Options con figure DHCP options whereas parameters configure values that are not optional or control how the DHCP server behaves Parameters including options declared before a section enclosed in curly brackets are consid ered global parameters Global parameters apply to all the sections below it SF iasctane If the configuration file is changed the changes do not take effect until the DHCP daemon is restarted with the command service dhcpd restart In Example 25 1 the routers subnet mask domain name domain name servers and time offset options are used for any host statements declared below it As shown in Example 25 1 a subnet can be declared A subnet declaration must be included for every subnet in the network If it is not the DHCP server fails to start In this example there are global options for every DHCP client in the subnet and a range declared Clients are assigned an IP address within the range subnet 192 168 1 0 netmask 255 255 255 0 option routers 192 168 1 254 option subnet mask 255 255 255 07 option domain name example com option domain name servers 19251681 517 option time offset 18000 Eastern Standard Time range 192 168 1 10 192 168 1 100 Example 25 1 Subnet Declaration All subnets that share the same physical network should be declared within a shared network dec laration as shown in Example 25 2 Parameters within the shared
345. pts section and enter the name of the environment variable to unset Click OK to add it to the list This corresponds to the Unset Env directive To edit any of these environment values select it from the list and click the corresponding Edit button To delete any entry from the list select it and click the cooresponding Delete button To learn more about environment variables in Apache HTTP Server refer to the following http httpd apache org docs 2 0 env html Chapter 26 Apache HTTP Server Configuration 195 26 2 4 Directories Use the Directories page to configure options for specific directories This corresponds to the lt Directory gt directive PONR T R Site Configuration Default Directory Options Edit Logging ExecCGl FollowSymLinks Includes IncludesNOEXEC Environment Variables Leen Na a MA a al x pe ndexes SymLinksIfOwnerMatch Directories Directory Add P E Delete T Help 2 OK 38 Cancel Figure 26 6 Directories Click the Edit button in the top right hand corner to configure the Default Directory Options for all directories that are not specified in the Directory list below it The options that you choose are listed as the Options directive within the lt Directory gt directive You can configure the following options ExecCGI Allow execution of CGI scripts CGI scripts are not executed if this option i
346. r in conjunction with the 1 option s lt symbol name gt List sample data specific to a symbol name For example the following output is from the com mand oprofpp s StandardReadRequestFromClient usr X11R6 bin XFree86 vma samples symbol name 080e1360 12 100 StandardReadRequestFromClient 080e1360 1 8 33333 080e137f 1 8 33333 080e13bb 1 8 33333 080e13f4 1 8 33333 080e13fb 1 8 33333 080e144a 1 8 33333 080el5aa 1 8 33333 080e1668 1 8 33333 080e1803 1 8 33333 080e1873 1 8 33333 080e190a 2 16 6667 The first line is a summary for the symbol executable combination The first column consists of the virtual memory addresses sampled The second column is the number of samples for the memory address The third column is the percentage of samples for the memory address relative to the total number of samples for the symbol List sample data by symbols with more details than 1 For example vma samples symbol name 08083630 2 1 51515 xf 86Wakeup 08083641 1 50 080836al 1 50 080b8150 1 0 757576 Ones Chapter 43 OProfile 307 080b8179 1 100 080b8fb0 2 1251515 FlushClientCaches O80b8fb9 1 50 080b8fba 1 50 The data is the same as the 1 option except that for each symbol each virtual memory ad dress used is shown For each virtual memory address the number of samples and percentage of samples relative to the number of samples for the symbol is displayed g lt file name gt Generate output to a file in gprof fo
347. r kickstart upgrades Also choose the type of kickstart installation or upgrade screen from the following options CD ROM Choose this option to install or upgrade from the Red Hat Enterprise Linux CD ROMs NES Choose this option to install or upgrade from an NFS shared directory In the text field for the the NFS server enter a fully qualified domain name or IP address For the NFS directory enter the name of the NFS directory that contains the RedHat directory of the installation tree For example if the NFS server contains the directory mirrors redhat i386 RedHat enter mirrors redhat i386 for the NFS directory FTP Choose this option to install or upgrade from an FTP server In the FTP server text field enter a fully qualified domain name or IP address For the FTP directory enter the name of the FTP directory that contains the RedHat directory For example if the FTP server contains the directory mirrors redhat i386 RedHat enter mirrors redhat i386 for the FTP directory If the FTP server requires a username and password specify them as well e HTTP Choose this option to install or upgrade from an HTTP server In the text field for the HTTP server enter the fully qualified domain name or IP address For the HTTP directory enter the name of the HTTP directory that contains the RedHat directory For example if the HTTP server contains the directory mirrors redhat i386 RedHat enter mirrors redhat i386
348. r of events to be monitored exceeds the number of counters available for the processor multiple runs of OProfile can be used to collect data saving the sample data to different files each time To save the current set of sample files execute the following command replacing lt name gt with a unique descriptive name for the current session opcontrol save lt name gt The directory var lib oprofile samples name is created and the current sample files are copied to it 43 5 Analyzing the Data Periodically the OProfile daemon oprofiled collects the samples and writes them to the var lib oprofile samples directory Before reading the data make sure all data has been written to this directory by executing the following command as root opcontrol dump Each sample file name is based on the name of the executable with a closing curly bracket re placing each forward slash The file name ends with a hash mark followed by the counter Chapter 43 OProfile 305 number used for that sample file For example the following file includes the sample data for the sbin syslogd executable collected with counter 0 sbin syslogd 0 The following tools are available to profile the sample data once it has been collected op_time oprofpp op_to_source op_merge Use these tools along with the binaries profiled to generate reports that can be further analyzed waming The executable being profiled mus
349. r the anonymous user This option corresponds to anongid To edit an existing NFS share select the share from the list and click the Properties button To delete an existing NFS share select the share from the list and click the Delete button After clicking OK to add edit or delete an NFS share from the list the changes take place immedi ately the server daemon is restarted and the old configuration file is saved as etc exports bak The new configuration is written to etc exports The NFS Server Configuration Tool reads and writes directly to the etc exports configuration file Thus the file can be modified manually after using the tool and the tool can be used after modi fying the file manually provided the file was modified with correct syntax 23 3 1 Command Line Configuration If you prefer editing configuration files using a text editor or if you do not have the X Window System installed you can modify the configuration file directly The etc exports file controls what directories the NFS server exports Its format is as follows directory hostname options The only option that needs to be specified is one of sync or async sync is recommended If sync is specified the server does not reply to requests before the changes made by the request are written to the disk For example misc export speedy example com sync would allow users from speedy example com to mount misc export with the default read only p
350. ra packages not already installed A package group can have both standard and extra package members Standard packages are always available when the package group is installed Select the extra packages to be installed z V Extra Packages redhat config printer gui A GUI frontend for printconf X XFree86 Xvfb A virtual framebuffer X Windows System server for XFree86 4 XFree86 Xnest A nested XFree86 server rhn applet Panel applet for indication that newer Red Hat packages are available Z gdm The GNOME Display Manager Z desktop backgrounds extra Desktop background images redhat config date A graphical interface for modifying system date and time xterm xterm terminal emulator for the X Window System redhat config soundcard A graphical interface for detecting and configuring sounde CZ radhat confia xfron 26 _A_nranbical interface for canfinurina WE raa6 Kl J gt Package Information Full Name None Size None x Close Figure 17 2 Individual Package Selection After selecting package groups and individual packages to install click the Update button on the main window The number of packages to be installed and the amount of disk space required to install the packages as well as any package dependencies is displayed in a summary window If there are package dependencies they will be automatically added to the list of packages to install Click the Show De
351. rating a Key oo eeeeeeteeeeeeeeeeee 207 27 7 Generating a Certificate Request to Send to a CAL eee ee eeeeeeeeeeeeaes 209 27 8 Creating a Self Signed Certificate 00 eee eee escscseeeeeeseeeseeeeeesaeseeeeee 210 27 9 Testing The Certificate 27 AO ACCessing The Serverierenri i a ne a EEEIEE T a E 211 27 11 Additional Resources nas on ideae ae Ee eE r EnaA E 212 28 BIND Configuration 28 1 Adding a Forward Master Zone csscssessssseeeeseeeeeeeeeecseeseseeecneeneneeneeeeneeaee 213 28 2 Adding a Reverse Master Zone ecccssssssscessescseeeceeeeceeeseeecaeeseseeeeeeeaeeeeaeeeee 215 28 3 Adding a Slave Zone 217 29 Authentication Configuration 29 1 User Information 29 2 Authentication 220 29 3 Command Tine Version ses sensiya hr EK YERSE Eai 222 V System Configuration scscssscssssssscccsesssssssscscsssssssesesssssssessesesesessesessssssseesesesessssssesesesesasens 30 Console Access 30 1 Disabling Shutdown Via Ctrl Alt Del ce ececeseeseeceseeeeeeeecneeseeeeneeeeeees 227 30 2 Disabling Console Program Access 30 3 Disabling All Console ACCESS ssis segerrr ssrisosisarrsisoroi sisirain 30 4 Defining the Consoles cco oniinn a iaie aa AAEN EAE EEES 30 5 Making Files Accessible From the Console 30 6 Enabling Console Access for Other Applications 30 7 The floppy Group 31 Date and Time Configuration 31 1 Time and Date Properties
352. re lt version number gt is the version of the kernel installed on this system Additionally we use several different strategies to draw your attention to certain pieces of informa tion In order of how critical the information is to your system these items are marked as note tip important caution or a warning For example Note Remember that Linux is case sensitive In other words a rose is not a ROSE is not a rOsE Orio The directory usr share doc contains additional documentation for packages installed on your system Introduction v Boran If you modify the DHCP configuration file the changes will not take effect until you restart the DHCP daemon O caution Do not perform routine tasks as root use a regular user account unless you need to use the root account for system administration tasks A waming Be careful to remove only the necessary Red Hat Enterprise Linux partitions Removing other parti tions could result in data loss or a corrupted system environment 3 More to Come The Red Hat Enterprise Linux System Administration Guide is part of Red Hat s growing commitment to provide useful and timely support to Red Hat Enterprise Linux users As new tools and applications are released this guide will be expanded to include them 3 1 Send in Your Feedback If you spot a typo in the Red Hat Enterprise Linux System Administration Guide or if you have thought of a way to make this manual better w
353. re 12 4 RAID Array Created 86 Chapter 12 Software RAID Configuration redhat Chapter 13 LVM Configuration LVM can be configured during the graphical installation process or during a kickstart installation You can use the utilities from the 1vm package to create your LVM configuration but these instructions focus on using Disk Druid during installation to complete this task Read Chapter 4 Logical Volume Manager LVM first to learn about LVM An overview of the steps required to configure LVM Create physical volumes from the hard drives Create volume groups from the physical volumes Create logical volumes from the volume groups and assign the logical volumes mount points Note You can only edit LVM volume groups in GUI installation mode In text installation mode you can assign mount points to existing logical volumes To create a logical volume group with logical volumes during installation 1 On the Disk Partitioning Setup screen select Manually partition with Disk Druid 2 Select New 3 Select physical volume LVM from the File System Type pulldown menu as shown in Figure 13 1 Add Partition Mount Point Not Applicable v File System Type physical volume LVM hda 19469 MB Maxtor 52049H3 Allowable Drives CO hdb 19469 MB Maxtor 52049H3 Size MB 30000 Additional Size Options Fixed size O Fill all space up to MB O Fill to maximum allowable size
354. re than one unit mask the hexadecimal values must be combined using a bitwise or operation opcontrol ctrN event lt event name gt ctrN count lt sample rate gt ctrN unit mask lt value gt 43 2 3 Separating Kernel and User space Profiles By default kernel mode and user mode information is gathered for each event To configure OProfile not to count events in kernel mode for a specific counter execute the following command where N is the counter number opcontrol ctrN kernel 0 Execute the following command to start profiling kernel mode for the counter again opcontrol ctrN kernel 1 To configure OProfile not to count events in user mode for a specific counter execute the following command where N is the counter number opcontrol ctrN user 0 Execute the following command to start profiling user mode for the counter again opcontrol ctrN user 1 When the OProfile daemon writes the profile data to sample files it can separate the kernel and library profile data into separate sample files To configure how the daemon writes to sample files execute the following command as root opcontrol separate lt choice gt lt choice gt can be one of the following none do not separate the profiles default library generate per application profiles for libraries kernel generate per application profiles for the kernel and kernel modules all generate per application profiles for libraries a
355. re which hosts are allowed to connect to the PXE boot server For the command line version of this step refer to Section 14 3 1 Command Line Configuration To add hosts click the New button Hostname or IP Address Subnet client example com Operating System thel 3 as z C Serial Console Diskless OS Network OS Install Snapshot name Kickstart File Ethemet ethc S 3 Cancel OK Figure 14 3 Add a Host 94 Chapter 14 PXE Network Installations Enter the following information Hostname or IP Address Subnet Enter the IP address fully qualified hostname or a subnet of systems that should be allowed to connect to the PXE server for installations Operating System Select the operating system identifier to install on this client The list is populated from the network install instances created from the Network Installation Dialog Serial Console Select this option to use a serial console Kickstart File Specify the location of a kickstart file to use such as http server example com kickstart ks cfg This file can be created with the Kickstart Configurator Refer to Chapter 10 Kickstart Configurator for details Ignore the Snapshot name and Ethernet options They are only used for diskless environments 14 3 1 Command Line Configuration If the network server is not running X the pxeboot utility a part of the redhat config netboot package can be used to add hos
356. rectories options for the virtual hosts are the same directives that you set when you clicked the Edit Default Settings button except the options set here are for the individual virtual hosts that you are configuring Refer to Section 26 2 Default Settings for details on these options 26 4 Server Settings The Server tab allows you to configure basic server settings The default settings for these options are appropriate for most situations Main Virtual Hosts Server Performance Tuning Lock File vat lock httpd lock v Browse PID File vat run httpd pid v Browse Core Dump Directory etc httpd w Browse User apache Group apache 2 OK Cancel T Heip Figure 26 10 Server Configuration The Lock File value corresponds to the LockFile directive This directive sets the path to the lockfile used when the server is compiled with either USE_FCNTL_SERIALIZED_ACCEPT or USE_FLOCK_SERIALIZED_ACCEPT It must be stored on the local disk It should be left to the default value unless the logs directory is located on an NFS share If this is the case the default value should be changed to a location on the local disk and to a directory that is readable only by root The PID File value corresponds to the PidFile directive This directive sets the file in which the server records its process ID pid This file should only be readable by r
357. repair the system 11 1 Common Problems You might need to boot into one of these recovery modes for any of the following reasons You are unable to boot normally into Red Hat Enterprise Linux runlevel 3 or 5 You are having hardware or software problems and you want to get a few important files off of your system s hard drive You forgot the root password 11 1 1 Unable to Boot into Red Hat Enterprise Linux This problem is often caused by the installation of another operating system after you have installed Red Hat Enterprise Linux Some other operating systems assume that you have no other operating systems on your computer They overwrite the Master Boot Record MBR that originally contained the GRUB or LILO boot loader If the boot loader is overwritten in this manner you will not be able to boot Red Hat Enterprise Linux unless you can get into rescue mode and reconfigure the boot loader Another common problem occurs when using a partitioning tool to resize a partition or create a new partition from free space after installation and it changes the order of your partitions If the partition number of your partition changes the boot loader might not be able to find it to mount the partition To fix this problem boot in rescue mode and modify boot grub grub conf if you are using GRUB or etc lilo conf if you are using LILO You must also run the sbin 1ilo command anytime you modify the LILO configuration file 11 1 2
358. restart X After GNOME is started a dialog box will appear prompting you for your passphrase s Enter the passphrase requested If you have both DSA and RSA key pairs configured you will be prompted for both From this point on you should not be prompted for a password by ssh scp or sftp 162 Chapter 22 OpenSSH 22 3 4 5 Configuring ssh agent The ssh agent can be used to store your passphrase so that you do not have to enter it each time you make a ssh or scp connection If you are not running the X Window System follow these steps from a shell prompt If you are running GNOME but you do not want to configure it to prompt you for your passphrase when you log in see Section 22 3 4 4 Configuring ssh agent with GNOME this procedure will work in a terminal window such as an XTerm If you are running X but not GNOME this procedure will work in a terminal window However your passphrase will only be remembered for that terminal window it is not a global setting 1 At a shell prompt type the following command exec usr bin ssh agent S SHELL 2 Then type the command ssh add and enter your passphrase s If you have more than one key pair configured you will be prompted for each one 3 When you log out your passphrase s will be forgotten You must execute these two commands each time you log in to a virtual console or open a terminal window 22 4 Additional Resources The OpenSSH and OpenSSL projects are in constant develo
359. rinter Notification Icon Clicking on the printer notification icon starts the GNOME Print Manager to display a list of current print jobs Also located on the Panel is a Print Manager icon To print a file from Nautilus browse to the location of the file and drag and drop it on to the Print Manager icon on the Panel The window shown in Figure 36 16 is displayed Click OK to start printing the file Printer Name Properties State Printer idle f Set as default Type Created by redhat config printer 0 6 x Location Comment HP LaserJet 4Si Foomatic ljet4 Page selection Copies All pages Number of copies 1 Pe M Collate copies C Pages L T Reverse order Enter page numbers and or E 1 X groups of pages to print separated by commas 1 2 5 10 12 17 Options Print All pages j Cancel Figure 36 16 Print Verification Window 264 Chapter 36 Printer Configuration To view the list of print jobs in the print spool from a shell prompt type the command 1pq The last few lines will look similar to the following Rank Owner ID Class Job Files Size Time active user localhost 902 A 902 sample txt 2050 01 20 46 Example 36 1 Example of 1pq output If you want to cancel a print job find the job number of the request with the command 1pq and then use the command lprm job number For example 1prm 902 would cancel the print job in Example 36 1 You must have proper permissions to cancel
360. rmat If the generated file is named gmon out gprof can be used to further analyze the data Refer to the gprof man page for details Other options to further restrict the data are as follows f lt file name gt Use the specified sample file lt file name gt By default the sample file in var lib oprofile samples is used Use this option to specify a sample file from a previous session i lt file name gt Use lt file name gt as the name of the executable for which to retrieve data Demangle C symbol names Demangle C symbol names and simplify STL library demangled names counter lt number gt Gather information from a specific counter The default counter is 0 if not specified Display the line number in the source code for each sample When the executable was compiled GCC s g option should have been used Otherwise this option can not display the line numbers None of the Red Hat Enterprise Linux executables are compiled with this option by default vma samples symbol name linear info 0806cbb0 0 0 _start sysdeps i386 elf start S 47 e lt symbol name gt Exclude the comma separated list of symbols from the output sk Display an additional column containing the shared library This option only produces results if the separate library option to opcont rol is specified when configuring OProfile and if the dump gprof file option is not used in conjunction with this option t lt format gt
361. rnel enter the name and location of the vmlinux file for the kernel to monitor in the Kernel image file text field To configure OProfile not to monitor the kernel select No kernel image Setup Configuration Kemel image file boot vmlinux 2 4 21 1 1931 2 349 2 2 entsmp _ C No kemel image C verbose C Per application kemel samples files Per application shared libs samples files Profiler running 1 hours 44 mins 32 interrupts second total 176226 Elush profiler data Stop profiler Save and quit Figure 43 2 OProfile Configuration If the Verbose option is selected the oprofiled daemon log includes more information If Per application kernel samples files is selected OProfile generates per application profiles for the kernel and kernel modules as discussed in Section 43 2 3 Separating Kernel and User space Profiles This is equivalent to the opcontrol separate kernel command If Per application shared libs samples files is selected OProfile generates per application profiles for libraries This is equiva lent to the opcontrol separate library command 312 Chapter 43 OProfile To force data to be written to samples files as discussed in Section 43 5 Analyzing the Data click the Flush profiler data button This is equivalent to the opcont rol dump command To start OProfile from the graphical interface click Start profiler To stop the profiler click Stop profil
362. rocesses use the command ps aux This list is a static list in other words it is a snapshot of what is running when you invoked the command If you want a constantly updated list of running processes use top as described below The ps output can be long To prevent it from scrolling off the screen you can pipe it through less ps aux less You can use the ps command in combination with the grep command to see if a process is running For example to determine if Emacs is running use the following command ps ax grep emacs The top command displays currently running processes and important information about them in cluding their memory and CPU usage The list is both real time and interactive An example of top s output is provided as follows 19311304 up 7 25 9 users load average 0 00 0 05 0 12 89 processes 88 sleeping 1 running 0 zombie 0 stopped CPU states cpu user nice system irq softirq iowait idle total 6 6 0 0 0 0 0 0 0 0 0 0 192 8 cpu00 6 7 0 0 0 1 0 1 0 0 0 0 92 8 cpu01 0 0 0 0 0 0 0 0 0 0 0 0 100 0 Mem 1028556k av 241972k used 786584k free 0k shrd 37712k buff 162316k active 18076k inactive Swap 1020116k av Ok used 1020116k free 99340k cached PID USER PRI NI SIZE RSS SHARE STAT CPU SMEM TIME CPU COMMAND 1899 root 15 017728 12M 4172 S 6 5 1 2 111 20 0x 6380 root 15 O 1144 1144 884 R Bsa Wst 0 00 0 top 1 root 15 0 488 488 432 S 0 0 0 0 0 05 1 init 2 root RT 0 0 0 0 SW 0 0 0 0 0 00 0
363. rocessor type the events monitored can be changed and counter 0 for the processor is set to a time based event by default If more than one counter exists on the processor 302 Chapter 43 OProfile the counters other than counter 0 are not set to an event by default The default events monitored are shown in Table 43 3 0 Pentium Pro Pentium CPU CLK _UNHALTED The processor s clock is not halted II Pentium II Athlon AMD64 Pentium 4 HT and GLOBAL_POWER_EVENTS The time during which the processor is non ae oe oe a Itanium 2 CPU_ lcpucYcLES o CPU CPU Cycles sd TIMER_INT Sample for each timer interrupt Table 43 3 Default Events The number of events that can be monitored at one time is determined by the number of counters for the processor However it is not a one to one correlation on some processors certain events must be mapped to specific counters To determine the number of counters available execute the following command cat dev oprofile cpu_type The events available vary depending on the processor type To determine the events available for profiling execute the following command as root the list is specific to the system s processor type op_help The events for each counter can be configured via the command line or with a graphical interface If the counter can not be set to a specific event an error message is displayed To set the event for each configurable counter via the command line
364. rrently running When the system is rebooted it is booted in to the runlevel specified in etc inittab 21 2 TCP Wrappers Many UNIX system administrators are accustomed to using TCP wrappers to manage access to certain network services Any network services managed by xinetd as well as any program with built in support for libwrap can use TCP wrappers to manage access xinetd can use the etc hosts allow and etc hosts deny files to configure access to system services As the names imply host s allow contains a list of rules that allow clients to access the network services controlled by xinetd and hosts deny contains rules to deny access The hosts allow file takes precedence over the hosts deny file Permissions to grant or deny access can be based on individual IP address or hostnames or on a pattern of clients Refer to the Red Hat Enterprise Linux Reference Guide and host s_access in section 5 of the man pages man 5 hosts_access for details 21 2 1 xinetd To control access to Internet services use xinetd which is a secure replacement for inetd The xinetd daemon conserves system resources provides access control and logging and can be used to start special purpose servers xinetd can be used to provide access only to particular hosts to deny access to particular hosts to provide access to a service at certain times to limit the rate of incoming connections and or the load created by connections and more xinetdruns constantl
365. rties Tool redhat config users See user configuration and group configuration redhat config xfree86 See X Configuration Tool redhat control network See Network Device Control redhat logviewer See Log Viewer redhat switch mail See Mail Transport Agent Switcher redhat switch mail nox See Mail Transport Agent Switcher rescue mode definition of 80 utilities available 81 resize2fs 2 resolution 237 RHN See Red Hat Network rmmod 286 RPM 103 additional resources 112 book about 112 checking package signatures 109 dependencies 106 design goals 103 determining file ownership with 110 documentation with 111 file conflicts resolving 105 finding deleted files with 110 freshen 107 freshening packages 107 GnuPG 109 graphical interface 113 installing 104 with Package Management Tool 114 mdS5sum 109 preserving configuration files 107 querying 108 querying for file list 111 querying uninstalled packages 111 tips 110 uninstalling 106 with Package Management Tool 115 upgrading 107 using 104 verifying 108 website 112 RSA keys generating 159 RSA Version keys generating 161 runlevel 1 81 runlevels 151 S Samba 171 additional resources 178 configuration 171 174 default 171 smb conf 171 encrypted passwords 175 findsmb 178 graphical configuration 171 adding a share 174 configuring server settings 172 managing Samba users 173 list of active connections 177 pam_sm
366. ructions This is an important advantage for several rea sons For instance if a new version of a program comes out you do not necessarily have to start from scratch to get it to compile You can look at the patch to see what you might need to do All the compiled in defaults and all of the changes that were made to get the software to build properly are easily visible using this technique The goal of keeping sources pristine may only seem important for developers but it results in higher quality software for end users too We would like to thank the folks from the BOGUS distribution for originating the pristine source concept 16 2 Using RPM RPM has five basic modes of operation not counting package building installing uninstalling up grading querying and verifying This section contains an overview of each mode For complete de tails and options try rpm help or turn to Section 16 5 Additional Resources for more information on RPM 16 2 1 Finding RPM Packages Before using an RPM you must know where to find them An Internet search returns many RPM repositories but if you are looking for RPM packages built by Red Hat they can be found at the following locations The Red Hat Enterprise Linux CD ROMs The Red Hat Errata Page available at http www redhat com apps support errata A Red Hat FTP Mirror Site available at http www redhat com download mirror htm Red Hat Network Refer to Chapter 18 Red Hat Netw
367. rusted third party authentication system which is commonly used in medium to large networks 7 Enable Kerberos Support Configure Kerberos SMB Authentication SMB authentication verifies user passwords by attempting to connect to a server which uses the SMB system message block protocol suite C Enable SMB Support Configure SMB amp Cancel Pox Figure 29 2 Authentication The following explains what each option configures Use Shadow Passwords Select this option to store passwords in shadow password format in the etc shadow file instead of et c passwd Shadow passwords are enabled by default during installation and are highly recommended to increase the security of the system The shadow utils package must be installed for this option to work For more information about shadow passwords refer to the Users and Groups chapter in the Red Hat Enterprise Linux Reference Guide Use MD5 Passwords Select this option to enable MDS passwords which allows passwords to be up to 256 characters instead of eight characters or less It is selected by default during installation and is highly recommended for increased security Enable LDAP Support Select this option to have standard PAM enabled applications use LDAP for authentication Click the Configure LDAP button to specify the following Use TLS to encrypt connections Use Transport Layer S
368. ry The directory to share via Samba The directory must exist Descriptions A brief description of the share Basic Permissions Whether users should only be able to read the files in the shared directory or whether they should be able to read and write to the shared directory On the Access tab select whether to allow only specified users to access the share or whether to allow all Samba users to access the share If you select to allow access to specific users select the users from the list of available Samba users The share is added immediately after clicking OK 24 2 2 Command Line Configuration Samba uses etc samba smb conf as its configuration file If you change this configuration file the changes do not take effect until you restart the Samba daemon with the command service smb restart Chapter 24 Samba 175 To specify the Windows workgroup and a brief description of the Samba server edit the following lines in your smb conf file workgroup WORKGROUPNAME server string BRIEF COMMENT ABOUT SERVER Replace WORKGROUPNAME with the name of the Windows workgroup to which this machine should belong The BRIEF COMMENT ABOUT SERVER is optional and is used as the Windows comment about the Samba system To create a Samba share directory on your Linux system add the following section to your smb conf file after modifying it to reflect your needs and your system sharename comment Insert a comment here
369. s to which to share the directory Refer to Section 23 3 2 Hostname Formats for an explanation of possible formats Basic permissions Specify whether the directory should have read only or read write permis sions Basic General Options User Access Directory tmp Browse Host s example com Basic permissions Read only Read Write 38 Cancel OK Figure 23 2 Add Share The General Options tab allows the following options to be configured Allow connections from port 1024 and higher Services started on port numbers less than 1024 must be started as root Select this option to allow the NFS service to be started by a user other than root This option corresponds to insecure Allow insecure file locking Do not require a lock request This option corresponds to insecure_locks Disable subtree checking If a subdirectory of a file system is exported but the entire file system is not exported the server checks to see if the requested file is in the subdirectory exported This check is called subtree checking Select this option to disable subtree checking If the entire file system is exported selecting to disable subtree checking can increase the transfer rate This option corresponds to no_subt ree_check Sync write operations on request Enabled by default this option does not allow the server to reply to requests be
370. s file The iptables service is also started so that the firewall is activated immediately after saving the selected options If Disable firewall was selected the etc sysconfig iptables file is removed and the iptables service is stop immediately The options selected are also written to the etc sysconfig redhat config securitylevel file so that the setting can be restored the next time the application is started Do not edit this file by hand Even though the firewall is activated immediately the iptables service is not configured to start automatically at boot time refer to Section 20 2 Activating the iptables Service for details 20 2 Activating the iptables Service The firewall rules are only active if the iptables service is running To manually start the service use the command sbin service iptables restart To ensure that it is started when the system is booted issue the command sbin chkconfig level 345 iptables on The ipchains service is not included in Red Hat Enterprise Linux However if ipchains is in stalled for example an upgrade was performed and the system had ipchains previously installed the ipchains service should not be activated along with the iptables service To make sure the ipchains service is disabled and configured not to start at boot time execute the following two commands sbin service ipchains stop sbin chkconfig level 345 ipchains off The Services Configuration Tool can be used to en
371. s in the IP address field To specify more than one IP address separate each IP address with spaces To specify a port use the syntax IP Address Port Use to configure all ports for the IP address Specify the host name for the virtual host in the Server Host Name field In the Aliases section click Add to add a host name alias Adding an alias here adds a ServerAlias directive within the NameVirtualHost directive 26 3 1 2 SSL Note You can not use name based virtual hosts with SSL because the SSL handshake when the browser accepts the secure Web server s certificate occurs before the HTTP request which identifies the appropriate name based virtual host If you want to use name based virtual hosts they will only work with your non secure Web server General Options E Enable SSL support Site Configuration Ruane aay Logging Certificate File etc httpd conf ssl crt server crt Environment Variables Directories Certificate Key File fetc httpd conf ssl key server key Certificate Chain File etc httpd conf ssl crt ca crt Certificate Authority File etc httpd conf ssl crt ca bundle crt SSL Log File logs ssl_engine_log SSL Log Level Info sst Options O FakeBasicAuth L ExportCertData CompatEnvVars StrictRequire L OptRenegotiate T Help 2 OK 3 Cancel Figure 26 9 SSL Support If an Apache HTTP Server is not conf
372. s not chosen FollowSymLinks Allow symbolic links to be followed Includes Allow server side includes IncludesNOEXEC Allow server side includes but disable the exec and include com mands in CGI scripts Indexes Display a formatted list of the directory s contents if no DirectoryIndex such as index htm1 exists in the requested directory Multiview Support content negotiated multiviews this option is disabled by default SymLinksIfOwnerMatch Only follow symbolic links if the target file or directory has the same owner as the link To specify options for specific directories click the Add button beside the Directory list box The window shown in Figure 26 7 appears Enter the directory to configure in the Directory text field at the bottom of the window Select the options in the right hand list and configure the Order directive with the left hand side options The Order directive controls the order in which allow and deny directives are evaluated In the Allow hosts from and Deny hosts from text field you can specify one of the following 196 Chapter 26 Apache HTTP Server Configuration Allow all hosts Type a11 to allow access to all hosts Partial domain name Allow all hosts whose names match or end with the specified string e Full IP address Allow access to a specific IP address A subnet Such as 192 168 1 0 255 255 255 0 A network CIDR specification such
373. s resources on the network To include a post installation script type it in the text area O eaution Do not include the spost command It will be added for you For example to change the message of the day for the newly installed system add the following command to the bpost section echo Hackers will be punished gt etc motd Qr More examples can be found in Section 9 7 1 Examples 78 Chapter 10 Kickstart Configurator 10 11 1 Chroot Environment To run the post installation script outside of the chroot environment click the checkbox next to this option on the top of the Post Installation window This is equivalent to the using the nochroot option in the post section To make any changes to the newly installed file system in the post installation section outside of the chroot environment you must prepend the directory name with mnt sysimage For example if you select Run outside of the chroot environment the previous example needs to be changed to the following echo Hackers will be punished gt mnt sysimage etc motd 10 11 2 Use an Interpreter To specify a scripting language to use to execute the script select the Use an interpreter option and enter the interpreter in the text box beside it For example usr bin python2 2 can be specified for a Python script This option corresponds to using post interpreter usr bin python2 2 in your kickstart file 10 12 Saving the File To review the cont
374. s used 26 2 1 Site Configuration The default values for the Directory Page Search List and Error Pages will work for most servers If you are unsure of these settings do not modify them Directory Page Search List Logging Environment Variables index htm Directories index shtml Edit Delete List of files to search for when a directory is requested Eg index html index shtml etc Error Pages Error Code Behavior Location LM Edit Bad Request default 2 Authorization Required default Forbidden default Not Found default Method Not Allowed default x Error Code 400 Bad Request Default Error Page Footer Show footer with email address Help 2 OK Figure 26 3 Site Configuration The entries listed in the Directory Page Search List define the DirectoryIndex directive The DirectoryIndex is the default page served by the server when a user requests an index of a directory by specifying a forward slash at the end of the directory name For example when a user requests the page http www example com this_directory they are going to get either the Direct oryIndex page if it exists or a server generated directory list The 192 Chapter 26 Apache HTTP Server Configuration server will try to find one of the files listed in the Di rect oryIndex directive and will return the first one it finds If it does not find
375. s you add refer to the appropriate device For example you could add the following line lt scanner gt dev scanner dev usb scanner Of course make sure that dev scanner is really your scanner and not say your hard drive That is the first step The second step is to define what is done with those files Look in the last section of etc security console perms for lines similar to lt console gt 0660 lt floppy gt 0660 root floppy lt console gt 0600 lt sound gt 0640 root lt console gt 0600 lt cdrom gt 0600 root disk and add a line like lt console gt 0600 lt scanner gt 0600 root Then when you log in at the console you are given ownership of the dev scanner device with the permissions of 0600 readable and writable by you only When you log out the device is owned by root and still has the permissions 0600 now readable and writable by root only 30 6 Enabling Console Access for Other Applications To make other applications accessible to console users a bit more work is required First of all console access only works for applications which reside in sbin or usr sbin so the application that you wish to run must be there After verifying that do the following steps 1 Create a link from the name of your application such as our sample foo program to the usr bin consolehelper application cd usr bin ln s consolehelper foo 2 Create the file etc security console apps foo touch etc security
376. sbin new kernel pkg script that builds a new initrd image and adds new entries to the boot loader configuration file If the system has a SCSI adapter and the SCSI driver was compiled as a module or if the kernel was built with ext3 support as a module the default in Red Hat Enterprise Linux the initrd image is required 12 Even though the initrd image and boot loader modifications are made verify that they were done correctly and be sure to use the custom kernel version instead of 2 4 21 1 1931 2 399 ent Refer to Section 39 5 Verifying the Initial RAM Disk Image and Section 39 6 Verifying the Boot Loader for instructions on verifying these modifications A 3 Additional Resources For more information on the Linux kernel refer to the following resources A 3 1 Installed Documentation e usr src linux 2 4 Documentation This directory contains advanced documentation on the Linux kernel and its modules These documents are written for people interested in con tributing to the kernel source code and understanding how the kernel works A 3 2 Useful Websites http www redhat com mirrors LDP HOWTO Kernel HOWTO html The Linux Kernel HOWTO from the Linux Documentation Project http www kernel org pub linux docs lkml The linux kernel mailing list 318 Appendix A Building a Custom Kernel Index Symbols dev profile 309 dev shm 296 etc auto master 164 etc cups 249 etc exports 167 etc fstab 2
377. se UTC select the System clock uses UTC option UTC stands for the Universal Time Coordinated also known as Greenwich mean time GMT Other time zones are determined by adding or subtracting from the UTC time O redhat Chapter 32 Keyboard Configuration The installation program allows users to configure a keyboard layout for their systems To configure a different keyboard layout after installation use the Keyboard Configuration Tool To start the Keyboard Configuration Tool select the Main Menu button on the panel gt System Settings gt Keyboard or type the command redhat config keyboard at a shell prompt a Select the appropriate keyboard for the system 5p earup Wapropy Swedish Swiss French Swiss French latin1 Swiss German Swiss German latin1 Turkish Ukrainian United Kingdom U S International OK Figure 32 1 Keyboard Configuration Tool Select a keyboard layout from the list for example U S English and click OK For changes to take effect you should log out of your graphical desktop session and log back in 234 Chapter 32 Keyboard Configuration redhat Chapter 33 Mouse Configuration The installation program allows users to select the type of mouse connected to the system To configure a different mouse type for the system use the Mouse Configuration Tool To start the Mouse Configuration Tool select Main Menu Button on the Panel
378. se the tool To start the application from the desktop go to the Main Menu Button gt System Settings gt Date amp Time or type the command redhat config date ata shell prompt for example in an XTerm or a GNOME terminal 31 1 Time and Date Properties As shown in Figure 31 1 the first tabbed window that appears is for configuring the system date and time and the NTP daemon ntpd 4 May gt 4 2003 gt f Sun Mon Tue Wed Thu Fri sat 3 Houi 1 2 B M 5l 17 ve 18 19 20 21 Network Time Protocol Your computer can synchronize its clock with a remote time server using the Network Time Protocol Z Enable Network Time Protocol Serer clock redhat com v G hep 38 Cancel 2 OK Figure 31 1 Time and Date Properties To change the date use the arrows to the left and right of the month to change the month use the arrows to the left and right of the year to change the year and click on the day of the week to change the day of the week Changes take place after the OK button is clicked To change the time use the up and down arrow buttons beside the Hour Minute and Second in the Time section Changes take place until after the OK button is clicked The Network Time Protocol NTP daemon synchronizes the system clock with a remote time server or time source such as a satellite The application allows you to configure an NTP daemon to syn chronize your system clock with a remote s
379. secO ipsect TIN L mi Internet gateway0 gateway1 Bul 192 168 1 0 24 192 168 2 0 24 Figure 19 23 Network to Network IPsec Alternate network configurations options include a firewall between each IP router and the Internet and an Intranet firewall between each IPsec router and subnet gateway The IPsec router and the gateway for the subnet can be one system with two Ethernet devices one with a public IP address that acts as the IPsec router and one with a private IP address that acts as the gateway for the private subnet Each IPsec router can use the gateway for its private network or a public gateway to send the packets to the other IPsec router To configure a network to network IPsec connection use the following steps 1 Start the Network Administration Tool 2 From the IPsec tab select New 3 Click Forward to start configuring a network to network IPsec connection 4 Provide a one word nickname such as ipsecoO for the connection and select whether the con nection should be automatically activated when the computer starts Click Forward 5 Select Network to Network encryption VPN and click Forward 6 Select the type of encryption to use manual or automatic If manual is selected an encryption key must be provided later in the process If automatic is selected the racoon daemon is used to manage the encryption key If racoon is used the ipsec tools package must be instal
380. secure server a valid DNS name and not any aliases which the server may have The Email Address should be the email address for the webmaster or system administrator e Avoid any special characters like amp etc Some CAs reject a certificate request which contains a special character So if your company name includes an ampersand amp spell it out as and instead of amp e Do not use either of the extra attributes A challenge password and An optional company name To continue without entering these fields just press Enter to accept the blank default for both inputs The file etc httpd conf ssl csr server csr is created when you have finished entering your information This file is your certificate request ready to send to your CA After you have decided on a CA follow the instructions they provide on their website Their instruc tions tell you how to send your certificate request any other documentation that they require and your payment to them After you have fulfilled the CA s requirements they send a certificate to you usually by email Save or cut and paste the certificate that they send you as etc httpd conf ssl crt server crt Be sure to keep a backup of this file 27 8 Creating a Self Signed Certificate You can create your own self signed certificate Note that a self signed certificate does not provide the security guarantees of a CA signed certificate See Section 27 5 Types of Certific
381. sedn If you specified either enableldap or enableldapauth use this option to specify the DN distinguished name in your LDAP directory tree under which user information is stored This option is set in the etc 1dap conf file enableldaptls Use TLS Transport Layer Security lookups This option allows LDAP to send encrypted usernames and passwords to an LDAP server before authentication enablekrb5 Use Kerberos 5 for authenticating users Kerberos itself does not know about home directories UIDs or shells So if you enable Kerberos you will need to make users accounts known to this workstation by enabling LDAP NIS or Hesiod or by using the usr sbin useradd command to make their accounts known to this workstation If you use this option you must have the pam_krb5 package installed krb5realm The Kerberos 5 realm to which your workstation belongs krb5kdc The KDC or KDCs that serve requests for the realm If you have multiple KDCs in your realm separate their names with commas Chapter 9 Kickstart Installations krb5adminserver The KDC in your realm that is also running kadmind This server handles password chang ing and other administrative requests This server must be run on the master KDC if you have more than one KDC enablehesiod Enable Hesiod support for looking up user home directories UIDs and shells More information on setting up and using Hesiod on your network is in
382. selected uncheck the eth0 device and check the eth0_office device For example Figure 19 19 shows a profile called Office with the logical device eth0_office It is configured to activate the first Ethernet card using DHCP File Profile Help sf B New Edit Copy Di Deactivate Devices Hardware DNS Hosts You may configure network devices associated with 3 physical hardware here Multiple logical devices can be g associated with a single piece of hardware Profte status Device Nickname Type amp Active E etho etho Ethernet v Active ethO eth0_office erne amp Active fetho etho_home Ethemet Active Profile Office modified Figure 19 19 Office Profile Notice that the Home profile as shown in Figure 19 20 activates the eth0_home logical device which is associated with eth0 Chapter 19 Network Configuration 139 Eile Profile Help B New Edit Copy 2 x Activate Deactivate Devices Hardware DNS Hosts O You may configure network devices associated with physical hardware here Multiple logical devices can be associated with a single piece of hardware Profite Status Device Nickname Jive amp Active Ef etho etho Ethernet Q Active ethO ethO_office Ethernet Active ethO eth0_home eme Active Profile Home modified
383. seste 98 15 4 Finish Configuring the Diskless Environment 0 0 0 ccceseecseeeeeeesesenseeeeeee 98 15 5 Adding Hosts oe 15 0 BOOUNg the HOStS esses sexed saseccssctcben ier esra NeT eN EREE TEEN ESETERE P ATIO E ETSI Psi 99 TIL Package Management scsssssssssscssssssssssssesssssessesesssssssessesesesessesesssesesessesasesesesseseseseseosene 101 16 Package Management With RPM eissis cece eseececseeeeeeecaesesceeeeseeseseseeenessessseeseanseaees 103 16 1 RPM Design Goals 103 16 2 Using RPM 16 3 Checking a Package s Signature 16 4 Impressing Your Friends with RPM 16 5 Additional Resources 17 Package Management Tool 0 ccc ecceeececseseeceeeescscseecesseseseseseeesscseeeseneeaeas 171 Installing Packages nines rees ne aii ccaneeieuacsdiadevsansaveanteitaecrs 17 2 Removing Packages 18 Red Hat NetWork neonne eaa E E A E A s IV Network Related Configuration eseeseseesesreseosesrosesreseseosroreseosesroreseoseoroseseeeroreoroseeresesroseseese 19 Network Configuration eanna a teachin EV sadist RA SER 19 1 Overview 19 2 Establishing an Ethernet Connection cccssecsseseseeseeseseeeeeeeseceseeeeeeeeeaeeas 124 19 3 Establishing an ISDN Connection sssssssssssssesssssressstesssrestssrsreseseesererntsrestees 125 19 4 Establishing a Modem Connection 19 5 Establishing an xDSL Connection 19 6 Establishing a Token Ring Co
384. setting 4 Select which physical volumes to use for the volume group 5 Create logical volumes with mount points such as home Remember that boot can not be a logical volume To add a logical volume click the Add button in the Logical Volumes section A dialog window as shown in Figure 13 3 will appear Mount Point Eile System Type Logical Volume Name Size MB Make Logical Volume home Iv ext3 ti LogVoloo 2048 Max size is 4080 MB X Cancel OK Figure 13 3 Creating a Logical Volume Repeat these steps for each volume group you want to create Ox You may want to leave some free space in the logical volume group so you can expand the logical volumes later Onine Heip Disk Setup Choose where you would like Red Hat Linux to be installed Ifyou do not know how to partition your system or if you need help with using the manual partitioning tools refer to the Red Hat Linux Installation Guide Ifyou used automatic partitioning you can either accept the current partition settings click Next or modify the setup using the manual partitioning tool If you are manually partitioning your system you will see your current hard drive s and partitions displayed below Use the partitioning tool to add edit Brosso nase note Paritioning Drive idewnda Geom 2482 258 63 Model Maxtor 5204043 redhat Pes tomoa Drive idevhdb Geom 248225516
385. space Show Details 3 Cancel Continue Figure 17 4 Package Removal Summary Click Continue to start the removal process When it is finished an Update Complete message will appear Orio You can combine the installation and removal of packages by selecting package groups packages to be installed removed and then clicking Update The Completed System Preparation window will display the number of packages to be installed and removed 116 Chapter 17 Package Management Tool redhat Chapter 18 Red Hat Network Red Hat Network is an Internet solution for managing one or more Red Hat Enterprise Linux systems All Security Alerts Bug Fix Alerts and Enhancement Alerts collectively known as Errata Alerts can be downloaded directly from Red Hat using the Red Hat Update Agent standalone application or through the RHN website available at https rhn redhat com redhat a NETWORK eme Era Sare Sree uen tammyfox Sign Out Systems Q search No systems selected Manage Clear Your RHN Your Account Your Preferences Buy Now Total systems 5 No recent actions Out of date systems 5 Unentitled systems 2 Ungrouped systems 5 Inactive systems 2 secu vant Errata View All Updated Fetchmail packages fix security vulnerabil 2 W bore Updated Fetchmail packages fix security vulnerability 4 Enhancement Updated Net SNMP packages
386. ss does not work if the user logs in using the SSH protocol 1 Lock the user s password If the user does not exist use the useradd command to create the user account but do not give it a password so that it remains locked If the password is already enabled lock it with the command usermod L username 2 Force immediate password expiration Type the following command chage d 0 username This command sets the value for the date the password was last changed to the epoch January 1 1970 This value forces immediate password expiration no matter what password aging policy if any is in place Chapter 35 User and Group Configuration 245 3 Unlock the account There are two common approaches to this step The administrator can assign an initial password or assign a null password Aawaming Do not use the passwd command to set the password as it disables the immediate password expiration just configured To assign an initial password use the following steps Start the command line Python interpreter with the python command It displays the follow ing Python 2 2 2 1 Dec 10 2002 09 57 09 GCC 3 2 1 20021207 Red Hat Enterprise Linux 3 3 2 1 2 on linux2 Type help copyright credits or license for more information gt gt gt At the prompt type the following replacing password with the password to encrypt and salt with a combination of exactly 2 upper or lower case alphabetic characters dig
387. ssssssssssecssssessesesesssssessesesssessasaseseees Printer Configuration cccsssssssssssssssssssecesssssssssssesssessesessscssssesscsssnsessesesesesssessesesessseesessees Automated Tasks csccscssssssccsccsssssssssesssssssessssssessssssssssssessssssasesssesessssasessesesesesesesessesessseseeseees LOG Wiles isissccccsscenssscnssnsscougessuensen E E A E Upgrading the Kernel iniiis cneasa Sasco r iiaaaeaoe tit as doeet iiias eeen Kernel Modules ssssscsssssssssscsssssssssessssesssesessssessssssscssesesssessasscssesessssesossessevasesessseesessssseseees Mail Transport Agent MTA Configuration csssssssscsssssssssssssssssessssssesessssseseesesssseeene 289 E redhat Chapter 30 Console Access When normal non root users log into a computer locally they are given two types of special permis sions 1 They can run certain programs that they would not otherwise be able to run 2 They can access certain files normally special device files used to access diskettes CD ROMs and so on that they would not otherwise be able to access Since there are multiple consoles on a single computer and multiple users can be logged into the computer locally at the same time one of the users has to win the race to access the files The first user to log in at the console owns those files Once the first user logs out the next user who logs in owns the files In contrast every user who logs in at the console is all
388. stalled with the specified language set to the default logvol optional Create a logical volume for Logical Volume Management LVM with the syntax logvol lt mntpoint gt vgname lt name gt size lt size gt name lt name gt lt options gt The options are as follows noformat Use an existing logical volume and do not format it useexisting Use an existing logical volume and reformat it Create the partition first create the logical volume group and then create the logical volume For example part pv 01 size 3000 volgroup myvg pv 01 logvol vgname myvg size 2000 name rootvol mouse required Configures the mouse for the system both in GUI and text modes Options are device Device the mouse is on such as device ttyS0 emulthree If present simultaneous clicks on the left and right mouse buttons will be recognized as the middle mouse button by the X Window System This option should be used if you have a two button mouse After options the mouse type may be specified as one of the following alpsps 2 ascii asciips 2 atibm generic generic3 genericps 2 generic3ps 2 genericwheelps 2 genericusb generic3usb genericwheelusb geniusnm geniusnmps 2 geniusprops 2 geniusscrollps 2 geniusscrollps 2 thinking thinkingps 2 logitech logitechcc logibm logimman logimmanps 2 logimman logimmantps 2 logimmusb microsoft msnew msintelli msintellips 2 msintelli
389. start or restart to start or restart the service 21 6 Additional Resources For more information refer to the following resources 21 6 1 Installed Documentation The man pages for ntsysv chkconfig xinetd and xinetd conf man 5 hosts_access The man page for the format of host access control files in section 5 of the man pages 156 Chapter 21 Controlling Access to Services 21 6 2 Useful Websites http Awww xinetd org The xinetd webpage It contains a more detailed list of features and sample configuration files 21 6 3 Related Books Red Hat Enterprise Linux Reference Guide Red Hat Inc This companion manual contains detailed information about how TCP wrappers and xinetd allow or deny access as well as how to configure network access using them It also provides instructions for creating iptables firewall rules Red Hat Enterprise Linux Security Guide Red Hat Inc This manual discusses securing services with TCP wrappers and xinetd such as logging denied connection attempts redhat Chapter 22 OpenSSH OpenSSH is a free open source implementation of the SSH Secure SHell protocols It replaces telnet ftp rlogin rsh and rcp with secure encrypted network connectivity tools OpenSSH supports versions 1 3 1 5 and 2 of the SSH protocol Since OpenSSH version 2 9 the default protocol is version 2 which uses RSA keys as the default 22 1 Why Use OpenSSH If you use OpenSSH to
390. stem similar to the Firewall Configuration screen in the installation program Refer to Chapter 20 Basic Firewall Configuration for more information If you need more specific firewall rules refer to the iptables chapter in the Red Hat Enterprise Linux Reference Guide 21 1 Runlevels Before you can configure access to services you must understand Linux runlevels A runlevel is a state or mode that is defined by the services listed in the directory etc rc d rc lt x gt d where lt x gt is the number of the runlevel The following runlevels exist 152 Chapter 21 Controlling Access to Services 0 Halt 1 Single user mode 2 Not used user definable 3 Full multi user mode 4 Not used user definable e 5 Full multi user mode with an X based login screen e 6 Reboot If you use a text login screen you are operating in runlevel 3 If you use a graphical login screen you are operating in runlevel 5 The default runlevel can be changed by modifying the etc inittab file which contains a line near the top of the file similar to the following id 5 initdefault Change the number in this line to the desired runlevel The change do not take effect until you reboot the system To change the runlevel immediately use the command telinit followed by the runlevel number You must be root to use this command The telinit command does not change the etc inittab file it only changes the runlevel cu
391. stem It also creates three swap partitions one on each drive part raid 01 size 60 ondisk sda part raid 02 size 60 ondisk sdb part raid 03 size 60 ondisk sdc part swap size 128 ondisk sda part swap size 128 ondisk sdb part swap size 128 ondisk sdc part raid 11 size 1 grow ondisk sda part raid 12 size 1 grow ondisk sdb part raid 13 size 1 grow ondisk sdc raid level 1 device md0 raid 01 raid 02 raid 03 raid usr level 5 device md1 raid 11 raid 12 raid 13 reboot optional Reboot after the installation is complete no arguments Normally kickstart displays a message and waits for the user to press a key before rebooting root pw required Sets the system s root password to the lt password gt argument rootpw iscrypted lt password gt Chapter 9 Kickstart Installations 53 iscrypted If this is present the password argument is assumed to already be encrypted skipx optional If present X is not configured on the installed system text optional Perform the kickstart installation in text mode Kickstart installations are performed in graphical mode by default timezone required Sets the system time zone to lt timezone gt which may be any of the time zones listed by timeconfig timezone utc lt timezone gt utc If present the system assumes the hardware clock is set to UTC Greenwich Mean time upgrade optional
392. t Office Productivity Sound and Video Graphics Games and Entertainment Authoring and Publishing Server Configuration Tools Web Server Mail Server Windows File Server Automatically Resolve Dependencies Figure 10 14 Package Selection The Package Selection window allows you to choose which package groups to install There are also options available to resolve and ignore package dependencies automatically Currently Kickstart Configurator does not allow you to select individual packages To install indi vidual packages modify the packages section of the kickstart file after you save it Refer to Section 9 5 Package Selection for details 76 Chapter 10 Kickstart Configurator 10 10 Pre Installation Script File Help Basic Configuration Pre Installation Script Installation Method Warming An error in this script might cause your kickstart installation to fail Do not include the pre command at the beginning Boot Loader Options Partition Information Use an interpreter Network Configuration Authentication Type your pre script below Firewall Configuration X Configuration Package Selection Pre Installation Script Post installation Script Figure 10 15 Pre Installation Script You can add commands to run on the system immediately after the kickstart file has been parse
393. t be used with these tools to analyze the data If it must change after the data is collected backup the executable used to create the samples as well as the sample files Samples for each executable are written to a single sample file Samples from each dynamically linked library are also written to a single sample file While OProfile is running if the executable being monitored changes and a sample file for the executable exists the existing sample file is automatically deleted Thus if the existing sample file is needed it must be backed up along with the executable used to create it before replacing the executable with a new version Refer to Section 43 4 Saving Data for details on how to backup the sample file 43 5 1 Using op_time The op_time tool provides an overview of all the executables being profiled The following is part of an example output 581 0 2949 0 0000 usr bin oprofiled 966 0 4904 0 0000 usr sbin cupsd 1028 0 5218 0 0000 usr sbin irqbalance 1187 0 6026 0 0000 bin bash 1480 0 7513 0 0000 usr bin slocate 2039 1 0351 0 0000 usr lib rpm rpmq 6249 3 1722 0 0000 usr X11R6 bin XFree86 8842 4 4885 0 0000 bin sed 31342 15 9103 0 0000 usr bin gdmgreeter 58283 29 5865 0 0000 no vmlinux 82853 42 0591 0 0000 usr bin perl Each executable is listed on its own line The first column is the number of samples recorded for the executable The second column is the percentage of samples relative to the total number of s
394. t can be exceeded for a certain amount of time That time is known as the grace period The grace period can be expressed in seconds minutes hours days weeks or months If any of the values are set to 0 that limit is not set In the text editor change the desired limits For example Disk quotas for user testuser uid 501 Filesystem blocks soft hard inodes soft hard dev hda3 440436 500000 550000 37418 0 0 To verify that the quota for the user has been set use the command quota testuser 6 1 5 Assigning Quotas per Group Quotas can also be assigned on a per group basis For example to set a group quota for the devel group use the command the group must exist prior to setting the group quota edquota g devel This command displays the existing quota for the group in the text editor Disk quotas for group devel gid 505 Filesystem blocks soft hard inodes soft hard dev hda3 440400 0 0 37418 0 0 Modify the limits save the file and then configure the quota To verify that the group quota has been set use the command quota g devel 6 1 6 Assigning Quotas per File System To assign quotas based on each file system enabled for quotas use the command edquota t 24 Chapter 6 Implementing Disk Quotas Like the other edquota commands this one opens the current quotas for the file system in the text editor Grace period before enforcing soft limits for users Time units may be days hours minutes or s
395. t installed if the kernel smp or kerne1 hugemem package was installed as well a section will exist for it as well Note that you do not have to rerun grub after making changes to this file NOTICE You have a boot partition This means that all kernel and initrd paths are relative to boot eg root hd0 0 kernel vmlinuz version ro root dev hda2 initrd initrd version img boot dev hda default 1 timeout 10 splashimage hd0 0 grub splash xpm gz title Red Hat Enterprise Linux 2 4 21 1 1931 2 399 ent root hd0 0 kernel vmlinuz 2 4 21 1 1931 2 399 ent ro root LABEL initrd initrd 2 4 21 1 1931 2 399 ent img title Red Hat Enterprise Linux 2 4 20 2 30 ent root hd0 0 kernel vmlinuz 2 4 20 2 30 ent ro root LABEL initrd initrd 2 4 20 2 30 ent img If a separate boot partition was created the paths to the kernel and initrd image are relative to boot Notice that the default is not set to the new kernel To configure GRUB to boot the new kernel by default change the value of the default variable to the title section number for the title section that contains the new kernel The count starts with 0 For example if the new kernel is the first title section set default to 0 Begin testing the new kernel by rebooting the computer and watching the messages to ensure that the hardware is detected properly 39 6 1 2 LILO If LILO is used as the boot loader confirm that the file etc 1lilo conf contai
396. t number If you want to specify more than one IP address with the same port number create an entry for each IP address If at all possible use an IP address instead of a domain name to prevent a DNS lookup failure Refer to http httpd apache org docs 2 0 dns caveats html for more information about Issues Regarding DNS and Apache Entering an asterisk in the Address field is the same as choosing Listen to all addresses Clicking the Edit button in the Available Addresses frame shows the same window as the Add button except with the fields populated for the selected entry To delete an entry select it and click the Delete button Qr If you set the server to listen to a port under 1024 you must be root to start it For port 1024 and above httpd can be started as a regular user Chapter 26 Apache HTTP Server Configuration 191 Listen to all addresses Q Address 192 168 1 4 4 l Port 80 Figure 26 2 Available Addresses 26 2 Default Settings After defining the Server Name Webmaster email address and Available Addresses click the Virtual Hosts tab and click the Edit Default Settings button The window shown in Figure 26 3 will appear Configure the default settings for your Web server in this window If you add a virtual host the settings you configure for the virtual host take precedence for that virtual host For a directive not defined within the virtual host settings the default value i
397. t specify the full path of the file for example usr bin 1s p lt packagefile gt queries the package lt packagefile gt There are a number of ways to specify what information to display about queried packages The following options are used to select the type of information for which you are searching These are called Information Selection Options i displays package information including name description release size build date install date vendor and other miscellaneous information 1 displays the list of files that the package contains s displays the state of all the files in the package d displays a list of files marked as documentation man pages info pages READMEs etc c displays a list of files marked as configuration files These are the files you change after in stallation to adapt the package to your system for example sendmail cf passwd inittab etc For the options that display lists of files you can add v to the command to display the lists in a familiar 1s 1 format 16 2 7 Verifying Verifying a package compares information about files installed from a package with the same in formation from the original package Among other things verifying compares the size MD5 sum permissions type owner and group of each file The command rpm v verifies a package You can use any of the Package Selection Options listed for querying to specify the packages you wish to verify A sim
398. t the application select Main Menu Button on the Panel gt System Settings gt Security Level or type the command redhat config securitylevel from a shell prompt for example in an XTerm or a GNOME terminal Gig ee Please choose the security level for the system Security level Enable firewall WWW HTTP FTP Trusted services SSH LI Telnet Mail SMTP etho Trusted devices Cancel 2 OK Figure 20 1 Security Level Configuration Tool f Note The Security Level Configuration Tool only configures a basic firewall If the system needs to allow or deny access to specific ports or if the system needs more complex rules refer to the Red Hat Enterprise Linux Reference Guide for details on configuring specific iptables rules Select one of the following options 148 Chapter 20 Basic Firewall Configuration Disable firewall Disabling the firewall provides complete access to your system and does no security checking Security checking is the disabling of access to certain services This should only be selected if you are running on a trusted network not the Internet or plan to do more firewall configuration later waming If you have a firewall configured or any customized firewall rules in the etc sysconfig iptables file the file will be deleted if you select Disable firewall and click OK to save the changes Enable firewall This o
399. t up and shut down multiple times Thus samples from multiple runs accumulate Use the command opcont rol reset to clear out the samples from previous runs Non CPU limited performance problems OProfile is oriented to finding problems with CPU limited processes OProfile does not identify processes that are asleep because they are waiting on locks or for some other event to occur for example an I O device to finish an operation In Red Hat Enterprise Linux only the multi processor SMP kernels have OProfile support enabled To determine which kernel is running issue the following command uname r 300 Chapter 43 OProfile If the kernel version returned ends in entsmp the multi processor kernel is running If it is not install it via Red Hat Network or from the distribution CDs even if the system is not a multi processor system The multi processor kernel can run an a single processor system 43 1 Overview of Tools Table 43 1 provides a brief overview of the tools provided with the oprofile package opcontrol Configures what data is collected Refer to Section 43 2 Configuring OProfile for details op_help Displays available events for the system s processor along with a brief description of each op_merge Merges multiple samples from the same executable Refer to Section 43 5 4 Using op_merge for details op_time Gives an overview of all profiled executables Refer to Section 43 5 1 Using op_time for details o
400. t3 1 4 Reverting to an ext2 File System Because ext3 is relatively new some disk utilities do not yet support it For example you may need to shrink a partition with resize2fs which does not yet support ext3 In this situation it may be necessary to temporarily revert a file system to ext2 To revert a partition you must first unmount the partition by logging in as root and typing umount dev hdbX In the above command replace dev hdb with the device name and X with the partition number For the remainder of this section the sample commands will use hdb1 for these values Next change the file system type to ext2 by typing the following command as root sbin tune2fs O has_journal dev hdb1 Check the partition for errors by typing the following command as root sbin e2fsck y dev hdb1 Chapter 1 The ext3 File System 3 Then mount the partition again as ext2 file system by typing mount t ext2 dev hdb1 mount point In the above command replace mount point with the mount point of the partition Next remove the journal file at the root level of the partition by changing to the directory where it is mounted and typing rm f journal You now have an ext2 partition If you permanently change the partition to ext2 remember to update the etc fstab file Chapter 1 The ext3 File System redhat Chapter 2 Swap Space 2 1 What is Swap Space Swap space in Linux is used when the amount of physical me
401. tails button to view the complete list of packages to be installed Completed System Preparation 1 packages are queued for installation Q This will take 1 120 Kilobytes of diskspace Show Details 38 Cancel Continue Figure 17 3 Package Installation Summary Click Continue to start the installation process When it is finished an Update Complete message will appear Chapter 17 Package Management Tool 115 Om If you use Nautilus to browse the files and directories on your computer you can also use it to install packages In Nautilus go to the directory that contains an RPM package they usually end in rpm and double click on the RPM icon 17 2 Removing Packages To remove all the package installed within a package group uncheck the checkbox beside it To remove individual packages click the Details button beside the package group and uncheck the indi vidual packages When you are finished selecting packages to remove click the Update button in the main window The application computes the amount of disk space that will be freed as well as the software package dependencies If other packages depend on the packages you selected to remove they will be auto matically added to the list of packages to be removed Click the Show Details button to view the list of packages to be removed Completed System Preparation 1 packages are queued for removal Q This will free up 1 046 Kilobytes of disk
402. ted You must be root to modify the etc fstab file The general syntax for the line in etc fstab is as follows server usr local pub pub nfs rsize 8192 wsize 8192 timeo 14 intr The mount point pub must exist on the client machine After adding this line to etc fstab on the client system type the command mount pub at a shell prompt and the mount point pub will be mounted from the server 164 Chapter 23 Network File System NFS 23 2 2 Mounting NFS File Systems using autofs A third option for mounting an NFS share is the use of autofs Autofs uses the automount daemon to manage your mount points by only mounting them dynamically when they are accessed Autofs consults the master map configuration file etc auto master to determine which mount points are defined It then starts an automount process with the appropriate parameters for each mount point Each line in the master map defines a mount point and a separate map file that defines the file systems to be mounted under this mount point For example the etc auto misc file might define mount points in the misc directory this relationship would be defined in the etc auto master file Each entry in auto master has three fields The first field is the mount point The second field is the location of the map file and the third field is optional The third field can contain information such as a timeout value For example to mount the directory proj52 on the remote machine pe
403. ter error 404 htm1 as the Location From the Default Error Page Footer menu you can choose one of the following options Show footer with email address Display the default footer at the bottom of all error pages along with the email address of the website maintainer specified by the ServerAdmin directive Refer to Section 26 3 1 1 General Options for information about configuring the ServerAdmin directive Show footer Display just the default footer at the bottom of error pages No footer Do not display a footer at the bottom of error pages 26 2 2 Logging By default the server writes the transfer log to the file var log httpd access_log and the error log to the var log httpd error_log file The transfer log contains a list of all attempts to access the Web server It records the IP address of the client that is attempting to connect the date and time of the attempt and the file on the Web server that it is trying to retrieve Enter the name of the path and file in which to store this information If the path and filename does not start with a slash the path is relative to the server root directory as configured This option corresponds to the TransferLog directive Chapter 26 Apache HTTP Server Configuration 193 Site Configuration Transfer Log E 109 to File logsfaccess Jog Environment Variables Directories Log to Program Use System Log Use custom logging facilities C
404. th a letter The printer name may contain letters numbers dashes and underscores _ Optionally enter a short description for the printer which can contain spaces Chapter 36 Printer Configuration 253 Select Networked UNIX LPD from the Select a queue type menu and click Forward Select a queue type Networked UNIX LPD z Server Queue servername example com pl is Help Cancel J Back gt Forward Figure 36 6 Adding a Remote LPD Printer Text fields for the following options appear Server The hostname or IP address of the remote machine to which the printer is attached Queue The remote printer queue The default printer queue is usually 1p Click Forward to continue Next select the printer type Refer to Section 36 7 Selecting the Printer Model and Finishing for details Boren The remote print server must accept print jobs from the local system 36 4 Adding a Samba SMB Printer To add a printer which is accessed using the SMB protocol such as a printer attached to a Microsoft Windows system click the New button in the main Printer Configuration Tool window The win dow shown in Figure 36 2 will appear Click Forward to proceed In the window shown in Figure 36 3 enter a unique name for the printer in the Name text field The printer name cannot contain spaces and must begin with a letter The printer name may contain letters numb
405. th today s fast CPUs Software RAID performance can excel against Hardware RAID The MD driver in the Linux kernel is an example of a RAID solution that is completely hardware independent The performance of a software based array is dependent on the server CPU performance and load For information on configuring Software RAID during installation refer to the Chapter 12 Software RAID Configuration For those interested in learning more about what Software RAID has to offer here is a brief list of the most important features Threaded rebuild process Kernel based configuration Portability of arrays between Linux machines without reconstruction Backgrounded array reconstruction using idle system resources Hot swappable drive support Automatic CPU detection to take advantage of certain CPU optimizations 3 4 RAID Levels and Linear Support RAID supports various configurations including levels 0 1 4 5 and linear These RAID types are defined as follows Level 0 RAID level 0 often called striping is a performance oriented striped data mapping technique This means the data being written to the array is broken down into strips and written across the member disks of the array allowing high I O performance at low inherent cost but pro vides no redundancy The storage capacity of a level 0 array is equal to the total capacity of the member disks in a Hardware RAID or the total capacity of member partitions in a S
406. the main Printer Configuration Tool window The window shown in Figure 36 1 will appear Click Forward to proceed In the window shown in Figure 36 3 enter a unique name for the printer in the Name text field The printer name cannot contain spaces and must begin with a letter The printer name may contain letters numbers dashes and underscores _ Optionally enter a short description for the printer which can contain spaces Select Networked Novell NCP from the Select a queue type menu Select a queue type Networked Novell NCP z Server User servername example com username Queue Password queuename fret is Help 3 Cancel gq Back p gt Eorward Figure 36 8 Adding an NCP Printer Text fields for the following options appear Server The hostname or IP address of the NCP system to which the printer is attached Queue The remote queue for the printer on the NCP system User The name of the user you must log in as to access the printer Password The password for the user specified in the User field above Next select the printer type Refer to Section 36 7 Selecting the Printer Model and Finishing for details waming If you require a username and password they are stored unencrypted in files only readable by root and Ipd Thus it is possible for others to learn the username and password if they have root access To avoid this
407. the minimum number of days between which the user must change passwords If the value is 0 the password does not expire M days Specify the maximum number of days for which the password is valid When the number of days specified by this option plus the number of days specified with the a option is less than the current day the user must change passwords before using the account d days Specify the number of days since January 1 1970 the password was changed I days Specify the number of inactive days after the password expiration before locking the account If the value is 0 the account is not locked after the password expires E date Specify the date on which the account is locked in the format YYYY MM DD Instead of the date the number of days since January 1 1970 can also be used W days Specify the number of days before the password expiration date to warn the user Table 35 3 chage Command Line Options OM If the chage command is followed directly by a username with no options it displays the current password aging values and allows them to be changed If a system administrator wants a user to set a password the first time the user log in the user s initial or null password can be set to expire immediately forcing the user to change it immediately after logging in for the first time To force a user to configure a password the first time the user logs in at the console follow these steps Note this proce
408. the request the username of the person who sent the request the hostname of the system that sent the request the job number and more If you are running a graphical desktop environment click the Printer Manager icon on the panel to start the GNOME Print Manager as shown in Figure 36 13 Printer Edit View Help 3 1 Printer 4 Figure 36 13 GNOME Print Manager It can also be started by selecting Main Menu Button on the Panel gt System Tools gt Print Manager To change the printer settings right click on the icon for the printer and select Properties The Printer Configuration Tool is then started Double click on a configured printer to view the print spool queue as shown in Figure 36 14 Chapter 36 Printer Configuration 263 Printer Edit View Help Document Owner Job Number Size Time Submitted anaconda ks cfg root 2048 bytes Wed 18 Dec 2002 01 23 58 AM EST 1 job in queue printer Figure 36 14 List of Print Jobs To cancel a specific print job listed in the GNOME Print Manager select it from the list and select Edit gt Cancel Documents from the pulldown menu If there are active print jobs in the print spool a printer notification icon might appears in the Panel Notification Area of the desktop panel as shown in Figure 36 15 Because it probes for active print jobs every five seconds the icon might not be displayed for short print jobs SOSQS SORE os ch Figure 36 15 P
409. the system uses NIS type the following command ypcat passwd mksmbpasswd sh gt etc samba smbpasswd The mksmbpasswd sh script is installed in your usr bin directory with the samba package 2 Change the permissions of the Samba password file so that only root has read and write permis sions chmod 600 etc samba smbpasswd 3 The script does not copy user passwords to the new file and a Samba user account is not active until a password is set for it For higher security it is recommended that the user s Samba password be different from the user s system password To set each Samba user s password use the following command replace username with each user s username smbpasswd username 176 Chapter 24 Samba 4 Encrypted passwords must be enabled Since they are enabled by default they do not have to be specifically enabled in the configuration file However they can not be disabled in the configuration file either In the file etc samba smb conf verify that the following line does not exist encrypt passwords no If it does exist but is commented out with a semi colon at the beginning of the line then the line is ignored and encrypted passwords are enabled If this line exist but is not commented out either remove it or comment it out To specifically enable encrypted passwords in the configuration file add the following lines to etc samba smb conf encrypt passwords yes smb passwd file etc samba smb
410. tically set IP addresses Manual IP Address Settings Address Subnet Mask Default Gateway Address 3 Cancel Back D Foward Figure 19 2 Ethernet Settings After configuring the Ethernet device it appears in the device list as shown in Figure 19 3 File Profile Help Br B 7 x New Edit Copy Delete Activate Deactivate Devices Hardware IPsec DNS Hosts 7 You may configure network devices associated with a iz physical hardware here Multiple logical devices can be i associated with a single piece of hardware Profile Status Device Nickname Type e ethO eth0 Figure 19 3 Ethernet Device Be sure to select File gt Save to save the changes After adding the Ethernet device you can edit its configuration by selecting the device from the device list and clicking Edit For example when the device is added it is configured to start at boot time by default To change this setting select to edit the device modify the Activate device when computer starts value and save the changes When the device is added it is not activated immediately as seen by its Inactive status To activate the device select it from the device list and click the Activate button If the system is configured to activate the device when the computer starts the default this step does not have to be performed again
411. tificates are issued for a particular IP address and domain name pair You must get a new certificate if you are changing your IP address or domain name If you have a certificate from VeriSign and you are changing your server software VeriSign is a widely used CA If you already have a VeriSign certificate for another purpose you may have been considering using your existing VeriSign certificate with your new secure server However you are not be allowed to because VeriSign issues certificates for one specific server software and IP address domain name combination If you change either of those parameters for example if you previously used a different secure server product the VeriSign certificate you obtained to use with the previous configuration will not work with the new configuration You must obtain a new certificate If you have an existing key and certificate that you can use you do not have to generate a new key and obtain a new certificate However you may need to move and rename the files which contain your key and certificate Move your existing key file to etc httpd conf ssl key server key Move your existing certificate file to etc httpd conf ssl crt server crt After you have moved your key and certificate skip to Section 27 9 Testing The Certificate If you are upgrading from the Red Hat Secure Web Server your old key htt psd key and certificate httpsd crt are located in etc httpd conf Move and rename
412. tion file If the imported configuration file has a print queue with the same name as an existing print queue on the system the print queue from the imported file will override the existing printer After importing the configuration file with or without the merge command you must restart the printer daemon Issue the command sbin service cups restart Chapter 36 Printer Configuration 261 36 11 Command Line Configuration If you do not have X installed and you do not want to use the text based version you can add a printer via the command line This method is useful if you want to add a printer from a script or in the post section of a kickstart installation 36 11 1 Adding a Local Printer To add a printer redhat config printer tui Xadd local options Options device node Required The device node to use For example dev 1p0 make make Required The IEEE 1284 MANUFACTURER string or the printer manufacturer s name as in the foomatic database if the manufacturer string is not available model mode1 Required The IEEE 1284 MODEL string or the printer model listed in the foomatic database if the model string is not available name name Optional The name to be given to the new queue If one is not given a name based on the device node such as lp0 will be used as default Optional Set this as the default queue After adding the printer use the following command to start restart the
413. tions from For example the following clears the parti tions on the first two drives on the primary IDE controller clearpart drives hda hdb initlabel Initializes the disk label to the default for your architecture for example msdos for x86 and gpt for Itanium It is useful so that the installation program does not ask if it should initialize the disk label if installing to a brand new hard drive linux Erases all Linux partitions none default Do not remove any partitions cmdline optional Perform the installation in a completely non interactive command line mode Any prompts for interaction will halt the install This mode is useful on S 390 systems with the x3270 console device optional On most PCI systems the installation program will autoprobe for Ethernet and SCSI cards prop erly On older systems and some PCI systems however kickstart needs a hint to find the proper devices The device command which tells the installation program to install extra modules is in this format device lt type gt lt moduleName gt opts lt options gt lt type gt Replace with either scsi or eth lt moduleName gt Replace with the name of the kernel module which should be installed Chapter 9 Kickstart Installations 45 opts Options to pass to the kernel module Note that multiple options may be passed if they are put in quotes For example opts aic152x 0x340 io 11 driverdisk optional Dr
414. tivate Devices Hardware IPsec DNS Hosts jec You may configure network devices associated with 3 o physical hardware here Multiple logical devices can be 9 associated with a single piece of hardware X Inactive tO trO Token Ring Figure 19 11 Token Ring Device Be sure to select File gt Save to save the changes After adding the device you can edit its configuration by selecting the device from the device list and clicking Edit For example you can configure whether the device is started at boot time When the device is added it is not activated immediately as seen by its Inactive status To activate the device select it from the device list and click the Activate button If the system is configured to activate the device when the computer starts the default this step does not have to be performed again 132 Chapter 19 Network Configuration 19 7 Establishing a CIPE Connection CIPE stands for Crypto IP Encapsulation It is used to configure an IP tunneling device For example CIPE can be used to grant access from the outside world into a Virtual Private Network VPN If you need to setup a CIPE device contact your system administrator for the correct values To configure a CIPE connection follow these steps 1 Click the Devices tab 2 Click the New button on the toolbar 3 Select CIPE VPN connection from the Device Type list and click Forward
415. tivated at the same time Refer to Section 19 13 Device Aliases for details about creating device aliases Profiles can be used to create multiple configuration sets for different networks A configuration set can include logical devices as well as hosts and DNS settings After configuring the profiles you can use the Network Administration Tool to switch back and forth between them 138 Chapter 19 Network Configuration By default there is one profile called Common To create a new profile select Profile gt New from the pull down menu and enter a unique name for the profile You are now modifying the new profile as indicated by the status bar at the bottom of the main window Click on an existing device already in the list and click the Copy button to copy the existing device to a logical network device If you use the New button a network alias will be created which is incorrect To change the properties of the logical device select it from the list and click Edit For example the nickname can be changed to a more descriptive name such as ethO_office so that it can be recognized more easily In the list of devices there is a column of checkboxes labeled Profile For each profile you can check or uncheck devices Only the checked devices are included for the currently selected profile For example if you create a logical device named ethO_office in a profile called Office and want to activate the logical device if the profile is
416. tives for this module Site Configuration Set for CGI Scripts Logging Environment Variable Value Add Environment Variables Directories Edit Delete Pass to CGI Scripts Add Edit Delete Unset for CGI Scripts Add Edi Delete E Help OK Cancel Figure 26 5 Environment Variables Use the Set for CGI Scripts section to set an environment variable that is passed to CGI scripts and SSI pages For example to set the environment variable MAXNUM to 50 click the Add button inside the Set for CGI Script section as shown in Figure 26 5 and type MAXNUM in the Environment Variable text field and 50 in the Value to set text field Click OK to add it to the list The Set for CGI Scripts section configures the Set Env directive Use the Pass to CGI Scripts section to pass the value of an environment variable when the server was first started to CGI scripts To see this environment variable type the command env at a shell prompt Click the Add button inside the Pass to CGI Scripts section and enter the name of the environment variable in the resulting dialog box Click OK to add it to the list The Pass to CGI Scripts section configures the PassEnv directive If you want to remove an environment variable so that the value is not passed to CGI scripts and SSI pages use the Unset for CGI Scripts section Click Add in the Unset for CGI Scri
417. to create a larger virtual drive In linear RAID the chunks are allocated sequentially from one member drive going to the next drive only when the first is completely filled This grouping provides no performance benefit as it is unlikely that any I O operations will be split between member drives Linear RAID also offers no redundancy and in fact decreases reliability if any one member drive fails the entire array cannot be used The capacity is the total of all member disks 3 Parity information is calculated based on the contents of the rest of the member disks in the array This information can then be used to reconstruct data when one disk in the array fails The reconstructed data can then be used to satisfy I O requests to the failed disk before it is replaced and to repopulate the failed disk after it has been replaced 4 RAID level 4 takes up the same amount of space as RAID level 5 but level 5 has more advantages For this reason level 4 is not supported 12 Chapter 3 Redundant Array of Independent Disks RAID redhat Chapter 4 Logical Volume Manager LVM 4 1 What is LVM LVM is a method of allocating hard drive space into logical volumes that can be easily resized instead of partitions With LVM the hard drive or set of hard drives is allocated to one or more physical volumes A physical volume can not span over more than one drive The physical volumes are combined into logical volume groups with the
418. to network 142 ISDN connection 126 activating 126 logical network devices 137 managing etc hosts 136 managing DNS Settings 135 managing hosts 136 modem connection 127 activating 128 overview 124 PPPoE connection 128 profiles 137 activating 139 restoring from file 145 saving to file 145 static IP 124 token ring connection 130 activating 131 wireless connection 133 activating 135 xDSL connection 128 activating 130 Network Device Control 137 139 Network File System See NFS Network Time Protocol See NTP 324 NFS etc fstab 163 additional resources 169 autofs See autofs command line configuration 167 configuration 163 diskless environment configuring for 98 exporting 165 hostname formats 168 mounting 163 over TCP 165 starting the server 168 status of the server 168 stopping the server 168 NFS Server Configuration Tool 165 NIS 220 NTP configuring 231 ntpd 231 ntpd 231 ntsysv 154 0 O Reilly amp Associates Inc 169 202 opcontrol See OProfile OpenLDAP 220 221 openldap clients 220 OpenSSH 157 additional resources 162 client 158 scp 158 sftp 159 ssh 158 DSA keys generating 160 generating key pairs 159 RSA keys generating 159 RSA Version 1 keys generating 161 server 157 etc ssh sshd_config 157 starting and stopping 157 ssh add 162 ssh agent 162 with GNOME 161 ssh keygen DSA 160 RSA 159 RSA Version 1 161 OpenSSL addition
419. to the following is displayed Device name incorrectly detected for symlink dev work The device dev hdb1 is now dev hddl The symlink dev work will now point to the new device name If a disk with the UUID is not found for example the disk was removed the following is displayed The device dev hdb1 no longer seems to exist Because of this the symlink dev work gt dev hdb1 will not be available The reference to this symlink in etc sysconfig devlabel will be ignored The entry for the device is not removed from the configuration file it is just ignored for this instance 1 Kudzu is a hardware probing tool run at system boot time to determine what hardware has been added or removed from the system 30 Chapter 7 User Defined Device Names 7 3 Additional Resources For more information concerning devlabel refer to these resources 7 3 1 Installed Documentation man devlabel The man page for devlabel discusses all of the options and includes a brief description of how it works man updfstab The man page for the updfstab program which is called by hotplug when a USB device is inserted man hotplug the man page for hotplug 7 3 2 Useful Websites http www dell com us en esg topics power_ps1q03 lerhaupt htm In Resolving Device Renam ing Issues in Linux the developer who wrote the devlabe1 program explains how it works http www lerhaupt com devlabel devlabel html The devel
420. top or restart a service immediately select the service from the list and click the appropriate button on the toolbar or choose the action from the Actions pulldown menu If the service is an xinetd service the action buttons are disabled because they can not be started or stopped individually If you enable disable an xinetd service by checking or unchecking the checkbox next to the service name you must select File gt Save Changes from the pulldown menu to restart xinetd and imme diately enable disable the xinetd service that you changed xinetd is also configured to remember the setting You can enable disable multiple xinetd services at a time and save the changes when you are finished 154 Chapter 21 Controlling Access to Services For example assume you check rsync to enable it in runlevel 3 and then save the changes The rsync service is immediately enabled The next time xinetd is started rsync is still enabled Mimin When you save changes to xinetd services xinetd is restarted and the changes take place imme diately When you save changes to other services the runlevel is reconfigured but the changes do not take effect immediately To enable a non xinetd service to start at boot time for the currently selected runlevel check the checkbox beside the name of the service in the list After configuring the runlevel apply the changes by selecting File gt Save Changes from the pulldown menu The runlevel configuration is c
421. tpd conf d ss1 conf For this file to be loaded and hence for mod_ss1 to work you must have the statement Include conf d conf in etc httpd conf httpd conf This statement is included by default in the default Apache HTTP Server configuration file 27 2 An Overview of Security Related Packages To enable the secure server you need to have the following packages installed at a minimum httpd The httpd package contains the httpd daemon and related utilities configuration files icons Apache HTTP Server modules man pages and other files used by the Apache HTTP Server mod_ssl The mod_ss1 package includes the mod_ss1 module which provides strong cryptography for the Apache HTTP Server via the Secure Sockets Layer SSL and Transport Layer Security TLS protocols openssl The openss1 package contains the OpenSSL toolkit The OpenSSL toolkit implements the SSL and TLS protocols and also includes a general purpose cryptography library Additionally other software packages provide certain security functionalities but are not required by the secure server to function 204 Chapter 27 Apache HTTP Secure Server Configuration httpd devel The httpd devel package contains the Apache HTTP Server include files header files and the APXS utility You need all of these if you intend to load any extra modules other than the modules provided with this product See the Red Hat Enterprise Linux Reference Guide for more information on loading
422. ts which are allowed to connect to the PXE server pxeboot a O lt os identifier gt r lt value gt lt host gt The following list describes the options e a Specifies that a host is to be added e o lt os identifier gt Replace lt os identifier gt with the operating system identifier as defined in Section 14 2 PXE Boot Configuration e r lt value gt W Replace lt value gt with the ram disk size e lt host gt Replace lt host gt with the IP address or hostname of the host to add 14 4 Starting the tftp Server On the DHCP server verify that the t ftp server package is installed with the command rpm q tftp server If it is not installed install it via Red Hat Network or the Red Hat Enterprise Linux CD ROMs For more information on installing RPM packages refer to Part IN Package Management tftp is an xinetd based service start it with the following commands sbin chkconfig level 345 xinetd on sbin chkconfig level 345 tftp on This command configures the t ftp and xinetd services to immediately turned on and also configures them to start at boot time in runlevels 3 4 and 5 14 5 Configuring the DHCP Server If a DHCP server does not already exist on the network configure one Refer to Chapter 25 Dy namic Host Configuration Protocol DHCP for details Make sure the configuration file contains the following so PXE booting is enabled for systems that support it allow booting allow
423. uding IP address gateway and DNS servers 25 1 Why Use DHCP DHCP is useful for fast delivery of client network configuration When configuring the client system the administrator can choose DHCP and not have to enter an IP address netmask gateway or DNS servers The client retrieves this information from the DHCP server DHCP is also useful if an admin istrator wants to change the IP addresses of a large number of systems Instead of reconfiguring all the systems he can just edit one DHCP configuration file on the server for the new set of IP addresses If the DNS servers for an organization changes the changes are made on the DHCP server not on the DHCP clients Once the network is restarted on the clients or the clients are rebooted the changes take effect Furthermore if a laptop or any type of mobile computer is configured for DHCP it can be moved from office to office without being reconfigured as long as each office has a DHCP server that allows it to connect to the network 25 2 Configuring a DHCP Server To configure a DHCP server modify the configuration file etc dhcpd conf DHCP also uses the file var 1ib dhcp dhcpd leases to store the client lease database Refer to Section 25 2 2 Lease Database for more information 25 2 1 Configuration File The first step in configuring a DHCP server is to create the configuration file that stores the network information for the clients Global options can be declared for
424. ue to Section 27 8 Creating a Self Signed Certificate 27 7 Generating a Certificate Request to Send toa CA Once you have created a key the next step is to generate a certificate request which you need to send to the CA of your choice Make sure you are in the usr share ssl certs directory and type in the following command make certreq Your system displays the following output and asks you for your passphrase unless you disabled the passphrase option umask 77 usr bin openssl req new key etc httpd conf ssl key server key out etc httpd conf ssl csr server csr Using configuration from usr share ssl openssl cnf Enter pass phrase Type in the passphrase that you chose when you were generating your key Your system displays some instructions and then ask for a series of responses from you Your inputs are incorporated into the certificate request The display with example responses looks similar to the following You are about to be asked to enter information that will be incorporated into your certificate request What you are about to enter is what is called a Distinguished Name or a DN There are quite a few fields but you can leave some blank For some fields there will be a default value If you enter the field will be left blank Country Name 2 letter code GB US State or Province Name full name Berkshire North Carolina Locality Name eg city Newbury Raleigh Organization Name eg comp
425. ult gateway as an IP address nameserver Primary nameserver as an IP address 50 Chapter 9 Kickstart Installations nodns Do not configure any DNS server netmask Netmask for the installed system hostname Hostname for the installed system part or partition required for installs ignored for upgrades Creates a partition on the system If more than one Red Hat Enterprise Linux installation exists on the system on different parti tions the installation program prompts the user and asks which installation to upgrade A waming All partitions created will be formatted as part of the installation process unless noformat and onpart are used lt mntpoint gt The lt mntpoint gt is where the partition will be mounted and must be of one of the fol lowing forms e lt path gt For example usr home swap The partition will be used as swap space To determine the size of the swap partition automatically use the recommended op tion swap recommended The minimum size of the automatically generated swap partition will be no smaller than the amount of RAM in the system and no bigger than twice the amount of RAM in the system e raid lt id gt The partition will be used for software RAID refer to raid pv lt id gt The partition will be used for LVM refer to Logvol size The minimum partition size in megabytes Specify an integer value here such as 500
426. up2date from a shell prompt Step 3 Register a System Profile Packages RPM information is important to determine what updated software packages are relevant to this system Z Include RPM packages installed on this system in my System Profile Below is a list of packages present on your system that RPM knows about Package Name version Release M 4Suite 0 11 1 14 Z GConf 1 0 9 12 GConf2 2 2 1 1 V Glide3 2001052 25 MAKEDEV 3 3 6 1 V ORBit 0 5 17 104 M ORBit2 26 2 1 By default all packages that RPM knows about will be included in your System Profile Uncheck any packages which you do not want to be included 3 Cancel lt q Back D gt Forward Figure 18 3 Registering with RHN After registering use one of the following methods to start receiving updates Select Main Menu Button gt System Tools gt Red Hat Network on your desktop Execute the command up2date from a shell prompt Use the RHN website at https rhn redhat com For more detailed instructions refer to the documentation available at http www redhat com docs manuals RHNetwork 0 Red Hat Enterprise Linux includes the Red Hat Network Alert Notification Tool a convenient panel icon that displays visible alerts when there is an update for your Red Hat Enterprise Linux system 120 Chapter 18 Red Hat Network IV Net
427. ups are always selected by default so it is not necessary to specify them in the packages Section Here is an example packages selection P g Spackages X Window System GNOME Desktop Environment Graphical Internet Sound and Video dhcp As you can see groups are specified one to a line starting with an symbol a space and then the full group name as given in the comps xml file Groups can also be specified using the id for the group such as gnome desktop Specify individual packages with no additional characters the dhcp line in the example above is an individual package You can also specify which packages not to install from the default package list autofs The following options are available for the packages option resolvedeps Install the listed packages and automatically resolve package dependencies If this option is not specified and there are package dependencies the automated installation will pause and prompt the user For example Spackages resolvedeps ignoredeps Ignore the unresolved dependencies and install the listed packages without the dependencies For example Spackages ignoredeps 56 Chapter 9 Kickstart Installations ignoremissing Ignore the missing packages and groups instead of halting the installation to ask if the installation should be aborted or continued For example Spackages ignoremissing 9 6 Pre installation Script You can add commands to ru
428. uration options that are not available in HTTP Configuration Tool you cannot use this tool The general steps for configuring the Apache HTTP Server using the HTTP Configuration Tool are as following Configure the basic settings under the Main tab Click on the Virtual Hosts tab and configure the default settings Under the Virtual Hosts tab configure the Default Virtual Host If you want to serve more than one URL or virtual host add the additional virtual hosts Configure the connections settings under the Performance Tuning tab 1 2 3 4 5 Configure the server settings under the Server tab 6 7 Copy all necessary files to the DocumentRoot and cgi bin directories 8 Exit the application and select to save your settings 190 Chapter 26 Apache HTTP Server Configuration 26 1 Basic Settings Use the Main tab to configure the basic server settings Main Virtual Hosts Server Performance Tuning Basic Setup Server Name Webmaster email address root localhost Available Addresses All available addresses on port 80 Add Edit Delete Set addresses for Apache to listen for requests on OK 38 Cancel T Heip Figure 26 1 Basic Settings Enter a fully qualified domain name that you have the right to use in the Server Name text area This option corresponds to the ServerName directive in httpd conf The ServerName d
429. usb msbm mousesystems mmseries mmhittab sun none This list can also be found in the usr lib python2 2 site packages rhpl mouse py file which is part of the rhp1 package If the mouse command is given without any arguments or it is omitted the installation program will attempt to auto detect the mouse This procedure works for most modern mice Chapter 9 Kickstart Installations 49 network optional Configures network information for the system If the kickstart installation does not require net working in other words it is not installed over NFS HTTP or FTP networking is not config ured for the system If the installation does require networking and network information is not provided in the kickstart file the installation program assumes that the installation should be done over eth0 via a dynamic IP address BOOTP DHCP and configures the final installed system to determine its IP address dynamically The network option configures networking information for kickstart installations via a network as well as for the installed system bootproto One of dhcp bootp or static It default to dhcp bootp and dhcp are treated the same The DHCP method uses a DHCP server system to obtain its networking configuration As you might guess the BOOTP method is similar requiring a BOOTP server to supply the networking configuration To direct a system to use DHCP network bootproto dhcp To direct a machine to use BOOTP t
430. use opcont rol opcontrol ctrlN event lt event name gt Replace N with the counter number starting with 0 and replace lt event name gt with the exact name of the event from op_help 43 2 2 1 Sampling Rate By default a time based event set is selected It creates approximately 2000 samples per second per processor If the timer interrupt is used the timer is set to whatever the jiffy rate is and is not user settable If the cpu_type is not timer each event can have a sampling rate set for it The sampling rate is the number of events between each sample snapshot When setting the event for the counter a sample rate can also be specified opcontrol ctrN event lt event name gt ctrN count lt sample rate gt Replace lt sample rate gt with the number of events to wait before sampling again The smaller the count the more frequent the samples For events that do not happen frequently a lower count may be needed to capture the event instances Chapter 43 OProfile 303 QO caution Be extremely careful when setting sampling rates Sampling too frequently can overload the system causing the system to appear as if it is frozen or causing the system to actually freeze 43 2 2 2 Unit Masks If the cpu_type is not timer unit masks may also be required to further define the event Unit masks for each event are listed with the op_help command The values for each unit mask are listed in hexadecimal format To specify mo
431. user process on x86 systems kernel BOOT used during installation only kernel pcmcia cs contains support for PCMCIA cards e kernel smp contains the kernel for multi processor systems The following are the key fea tures Multi processor support Support for more than 4 GB of RAM up to 64 GB for x86 278 Chapter 39 Upgrading the Kernel PAE Physical Address Extension or 3 level paging on x86 processors that support PAE kernel source Contains the source code files for the Linux kernel kernel utils Contains utilities that can be used to control the kernel or system hardware e kernel unsupported exists for some architectures Because it is not possible for Red Hat Enterprise Linux to contain support for every piece of hard ware available this package contains modules that are not supported by Red Hat Inc during instal lation or after installation The package is not installed during the installation process it must be installed after installation Drivers in the unsupported package are provided on a best effort basis updates and fixes may or may not be incorporated over time 39 2 Preparing to Upgrade Before upgrading the kernel take a few precautionary steps If the system has a diskette drive the first step is to make sure a working boot diskette exists for the system in case a problem occurs If the boot loader is not configured properly to boot the new kernel the system cannot be b
432. usr share doc glibc 2 x x README hesiod which is included in the glibc package Hesiod is an extension of DNS that uses DNS records to store information about users groups and various other items hesiodlhs The Hesiod LHS left hand side option set in etc hesiod conf This option is used by the Hesiod library to determine the name to search DNS for when looking up informa tion similar to LDAP s use of a base DN hesiodrhs The Hesiod RHS right hand side option set in etc hesiod conf This option is used by the Hesiod library to determine the name to search DNS for when looking up information similar to LDAP s use of a base DN To look up user information for jim the Hesiod library looks up jim passwd lt LHS gt lt RHS gt which should resolve to a TXT record that looks like what his passwd entry would look like jim 501 501 Jungle Jim home jim bin bash For groups the situation is identical except jim group lt LHS gt lt RHS gt would be used Looking up users and groups by number is handled by making 501 uid a CNAME for jim passwd and 501 gid a CNAME for jim group Note that the LHS and RHS do not have periods put in front of them when the library determines the name for which to search so the LHS and RHS usually begin with periods enablesmbauth Enables authentication of users against an SMB server typically a Samba or Windows server SMB authentication support does not know
433. ustom Log String Error Log Log to File logs error_log Log to Program Use System Log Log Level Error x Reverse DNS Lookup Reverse Lookup z T Heip 2 OK 3 Cancel Figure 26 4 Logging You can configure a custom log format by checking Use custom logging facilities and entering a custom log string in the Custom Log String field This configures the LogFormat directive Refer to http httpd apache org docs 2 0 mod mod_log_config html formats for details on the format of this directive The error log contains a list of any server errors that occur Enter the name of the path and file in which to store this information If the path and filename does not start with a slash the path is relative to the server root directory as configured This option corresponds to the ErrorLog directive Use the Log Level menu to set how verbose the error messages in the error logs will be It can be set from least verbose to most verbose to emerg alert crit error warn notice info or debug This option corresponds to the LogLevel directive The value chosen with the Reverse DNS Lookup menu defines the HostnameLookups directive Choosing No Reverse Lookup sets the value to off Choosing Reverse Lookup sets the value to on Choosing Double Reverse Lookup sets the value to double If you choose Reverse Lookup your server will automatically resolve the IP address for each con nection
434. ut printing in Linux http www cups org Documentation FAQs and newsgroups about CUPS redhat Chapter 37 Automated Tasks In Linux tasks can be configured to run automatically within a specified period of time on a specified date or when the system load average is below a specified number Red Hat Enterprise Linux comes pre configured to run important system tasks to keep the system updated For example the slocate database used by the 1ocate command is updated daily A system administrator can use automated tasks to perform periodic backups monitor the system run custom scripts and more Red Hat Enterprise Linux comes with several automated tasks utilities cron at and batch 37 1 Cron Cron is a daemon that can be used to schedule the execution of recurring tasks according to a combi nation of the time day of the month month day of the week and week Cron assumes that the system is on continuously If the system is not on when a task is scheduled it is not executed To schedule one time tasks refer to Section 37 2 At and Batch To use the cron service the vixie cron RPM package must be installed and the crond service must be running To determine if the package is installed use the rpm q vixie cron command To determine if the service is running use the command sbin service crond status 37 1 1 Configuring Cron Tasks The main configuration file for cron etc crontab contains the following lin
435. uthentication Configuration User Information Authentication Cache User Information NIS NIS is the Name Information Service Itis commonly used on small to medium networks Enable NIS Support Configure NIS LDAP The Lightweight Directory Access Protocol is a standard way of searching a directory which can hold arbitrary data in a structured hierarchy LDAP is increasingly being used in small to large networks C Enable LDAP Support Configure LDAP Hesiod Hesiod allows a system administrator to publish user and group information in DNS Itis sometimes used in very large networks C Enable Hesiod Support Configure Hesiod amp Cancel Box Figure 29 1 User Information The following list explains what each option configures Cache User Information Select this option to enable the name service cache daemon nscd and configure it to start at boot time The nscd package must be installed for this option to work Enable NIS Support Select this option to configure the system as an NIS client which connects to an NIS server for user and password authentication Click the Configure NIS button to specify the NIS domain and NIS server If the NIS server is not specified the daemon attempts to find it via broadcast The ypbind package must be installed for this option to work If NIS support is enabled
436. ving ACLs To determine the existing ACLs for a file or directory use the get facl command getfacl lt filename gt It returns output similar to the following file file owner tfox group tfox user irw user smoore r group r mask r other r If a directory is specified and it has a default ACL the default ACL is also displayed such as file file owner tfox group tfox user irw user smoore r group r mask r other r default user rwx default user tfox rwx default group r x default mask rwx default other r x 8 5 Archiving File Systems With ACLs A waming The tar and dump commands do not backup ACLs The star utility is similar to the tar utility in that it can be used to generate archives of files however some of its options are different Refer to Table 8 1 for a listing of more commonly used options For all available options refer to the star man page The star package is required to use this utility foption Deseription i O Creates an archive file n Do not extract the files use in conjunction with x to show what extracting the files does r Replaces files in the archive The files are written to the end of the archive file replacing any files with the same path and file name Displays the contents of the archive file 34 Chapter 8 Access Control Lists Updates the archive file The files are written to the end of the arc
437. was upgraded from a previous Red Hat Enterprise Linux version that used CUPS the upgrade process preserved the configured queues Using the Printer Configuration Tool requires root privileges To start the application select Main Menu Button on the Panel gt System Settings gt Printing or type the command redhat config printer This command automatically determines whether to run the graphical or text based version depending on whether the command is executed in the graphical desktop environment or from a text based console To force the Printer Configuration Tool to run as a text based application execute the command redhat config printer tui from a shell prompt mportant Do not edit the etc printcap file or the files in the etc cups directory Each time the printer daemon cups is started or restarted new configuration files are dynamically created The files are dynamically created when changes are applied with the Printer Configuration Tool as well Action Test Help a A New Edit Delete Default Apply Queue name Default Description printer my printer Figure 36 1 Printer Configuration Tool The following types of print queues can be configured Locally connected a printer attached directly to the computer through a parallel or USB port Networked CUPS IPP a printer that can be accessed over a TCP IP network via the Internet Printing Protocol also known as IPP for example
438. wing information Hostname or IP Address Subnet Specify the hostname or IP address of a system to add it as a host for the diskless environment Enter a subnet to specify a group of systems Operating System Select the diskless environment for the host or subnet of hosts Serial Console Select this checkbox to perform a serial installation Snapshot name Provide a subdirectory name to be used to store all of the read write content for the host Ethernet Select the Ethernet device on the host to use to mount the diskless environment If the host only has one Ethernet card select eth0 Ignore the Kickstart File option It is only used for PXE installations Hostname or IP Address Subnet 192 168 1 1 Operating System thel 3 as y C Serial Console Diskless OS Network OS Install Snapshot name 192 168 1 1 Kickstart File Ethernet etho x 3 Cancel OK Figure 15 1 Add Diskless Host In the existing snapshot directory in the diskless directory a subdirectory is created with the Snapshot name specified as the file name Then all of the files listed in snapshot files and snapshot files customare copied copy from the root directory to this new directory 15 6 Booting the Hosts Consult the documentation for your PXE card to configure the host to boot via PXE When the diskless client boots it mounts the remote root directory in the diskless directory as rea
439. with start Note If partitioning fails for any reason diagnostic messages will appear on virtual console 3 raid optional Assembles a software RAID device This command is of the form raid lt mntpoint gt level lt level gt device lt mddevice gt lt partitions gt 52 Chapter 9 Kickstart Installations lt mntpoint gt Location where the RAID file system is mounted If it is the RAID level must be unless a boot partition boot is present If a boot partition is present the boot partition must be level 1 and the root partition can be any of the available types The lt partitions gt which denotes that multiple partitions can be listed lists the RAID identifiers to add to the RAID array level RAID level to use 0 1 or 5 device Name of the RAID device to use such as mdO or md1 RAID devices range from md0 to md7 and each may only be used once spares Specifies the number of spare drives allocated for the RAID array Spare drives are used to rebuild the array in case of drive failure fstype Sets the file system type for the RAID array Valid values are ext2 ext3 swap and vfat noformat Use an existing RAID device and do not format the RAID array useexisting Use an existing RAID device and reformat it The following example shows how to create a RAID level 1 partition for and a RAID level 5 for usr assuming there are three SCSI disks on the sy
440. work Related Configuration After explaining how to configure the network this part discusses topics related to networking such as how to allow remote logins share files and directories over the network and set up a Web server Table of Contents 19 Network Configuratii sisisi siden osare eroii eris 123 20 Basic Firewall Configuration s ssesesseseoseseeseoseseoseoroseseoseoresroseseosesrosesroseoroseseeoresesreseoreseoseseseeee 147 21 Controlling Access to Services scssssssssssssssssssssesesesssssessssesssssessasssseseesesessssssseesesesssesserers 151 VPA IT a PERAE E A A EA OEE E 23 Network File System NFS 9 ESETT E OAR T EEA S E RATATE EEA OA EEEE ET E O OE E 25 Dynamic Host Configuration Protocol DHCP esessereseeseoreseosescoseoroseseeseoroseoreseoreseoseseenee 181 26 Apache HTTP Server Configuration sssssssscssssssssssscsssssssssssesesssssessssesessssssasesssssesseserers 189 27 Apache HTTP Secure Server Configuration sseseseesesroseoreseoreseoreoresesroseoresroreseoresroseseoseeeesee 203 28 BIND Configuration cssscsssssssssssscssssssssscssssssssssesesssssessssesesesesessssssesesessesssssssesseseseseseseees 213 29 Authentication Configuration sssssssssssssssssssscsesssssssscssessssseesasssssessssesesssessssesesssesesseress 219 redhat Chapter 19 Network Configuration To communicate with other computers computers need a network connection This is
441. x CD ROM 1 An alternate boot command is to boot off the Red Hat Enterprise Linux CD ROM 1 and have the kickstart file on a vfat or ext2 file system on a diskette To do so enter the following command at the boot prompt linux ks hd fd0 ks cfg With Driver Disk If you need to use a driver disk with kickstart specify the dd option as well For example to boot off a boot diskette and use a driver disk enter the following command at the boot prompt linux ks floppy dd Boot CD ROM If the kickstart file is on a boot CD ROM as described in Section 9 8 2 Creating a Kickstart Boot CD ROM insert the CD ROM into the system boot the system and enter the following command at the boot prompt where ks cfg is the name of the kickstart file linux ks cdrom ks cfg Other options to start a kickstart installation are as follows ks nfs lt server gt lt path gt The installation program will look for the kickstart file on the NFS server lt server gt as file lt path gt The installation program will use DHCP to configure the Ethernet card For example if your NFS server is server example com and the kickstart file is in the NFS share mydir ks cfg the correct boot command would be ks nfs server example com mydir ks cfg Chapter 9 Kickstart Installations 61 ks ks ks ks KS s KSS http lt server gt lt path gt The installation program will look for the kickstart file on the HTTP server lt
442. xceeded a appears in place of the corresponding the first represents the block limit and the second represents the inode limit The grace columns are normally blank If a soft limit has been exceeded the column contains a time specification equal to the amount of time remaining on the grace period If the grace period has expired none appears in its place 6 2 2 Keeping Quotas Accurate Whenever a file system is not unmounted cleanly due to a system crash for example it is necessary to run quotacheck However quot acheck can be run on a regular basis even if the system has not crashed Running the following command periodically keeps the quotas more accurate the options used have been described in Section 6 1 1 Enabling Quotas quotacheck avug Chapter 6 Implementing Disk Quotas 25 The easiest way to run it periodically is to use cron As root either use the crontab e command to schedule a periodic quot acheck or place a script that runs quot acheck in any one of the following directories using whichever interval best matches your needs e etc cron hourly e etc cron daily e etc cron weekly e etc cron monthly The most accurate quota statistics can be obtained when the file system s analyzed are not in active use Thus the cron task should be schedule during a time where the file system s are used the least If this time is various for different file systems with quotas run quotacheck for each file system at
443. y and listens on all ports for the services it manages When a connection request arrives for one of its managed services xinetd starts up the appropriate server for that service The configuration file for xinetd is etc xinetd conf but the file only contains a few defaults and an instruction to include the etc xinetd d directory To enable or disable an xinetd service edit its configuration file in the etc xinetd d directory If the disable attribute is set to yes the service is disabled If the disable attribute is set to no the service is enabled You can edit any of the xinetd configuration files or change its enabled status using the Services Configuration Tool ntsysv or chkconfig For a list of network services controlled by xinetd review the contents of the etc xinetd d directory with the command 1s etc xinetd d Chapter 21 Controlling Access to Services 153 21 3 Services Configuration Tool The Services Configuration Tool is a graphical application developed by Red Hat to configure which SysV services in the etc rc d init d directory are started at boot time for runlevels 3 4 and 5 and which xinetd services are enabled It also allows you to start stop and restart SysV services as well as restart xinetd To start the Services Configuration Tool from the desktop go to the Main Menu Button on the Panel gt System Settings gt Server Settings gt Services or type the command redhat config services at a shell prompt
444. y and they were mounted successfully you are in single user mode Even if your file system is mounted the default root partition while in rescue mode is a temporary root partition not the root partition of the file system used during normal user mode runlevel 3 or 5 If you selected to mount your file system and it mounted successfully you can change the root partition of the rescue mode environment to the root partition of your file system by executing the following command chroot mnt sysimage This is useful if you need to run commands such as rpm that require your root partition to be mounted as To exit the chroot environment type exit and you will return to the prompt If you selected Skip you can still try to mount a partition manually inside rescue mode by creating a directory such as foo and typing the following command mount t ext3 dev hda5 foo In the above command foo is a directory that you have created and dev hda5 is the partition you want to mount If the partition is of type ext 2 replace ext 3 with ext2 If you do not know the names of your partitions use the following command to list them fdisk 1 From the prompt you can run many useful commands such as e list harddrives to list the hard drives in the system ssh scp and ping if the network is started dump and restore for users with tape drives parted and fdisk for managing partitions e rpm for installing or upgrading software e joe for
445. yes is its sole argument any invalid partition tables found on disks are initialized This will destroy all of the contents of disks with invalid partition tables This command should be in the following format zerombr yes No other format is effective Chapter 9 Kickstart Installations 55 Sinclude Use the include path to file command to include the contents of another file in the kickstart file as though the contents were at the location of the include command in the kick start file 9 5 Package Selection Use the packages command to begin a kickstart file section that lists the packages you would like to install this is for installations only as package selection during upgrades is not supported Packages can be specified by group or by individual package name The installation program defines several groups that contain related packages Refer to the RedHat base comps xm1 file on the first Red Hat Enterprise Linux CD ROM for a list of groups Each group has an id user visibility value name description and package list In the package list the packages marked as mandatory are always installed if the group is selected the packages marked default are selected by default if the group is selected and the packages marked optional must be specifically selected even if the group is selected to be installed In most cases it is only necessary to list the desired groups and not individual packages Note that the Core and Base gro
446. your key and certificate so that the secure server can use them Use the following two commands to move and rename your key and certificate files mv etc httpd conf httpsd key etc httpd conf ssl key server key mv etc httpd conf httpsd crt etc httpd conf ssl crt server crt Then start your secure server with the command sbin service httpd start For a secure server you are prompted to enter your passphrase After you type it in and press Enter the server starts 27 5 Types of Certificates If you installed your secure server from the RPM package provided by Red Hat a random key and a test certificate are generated and put into the appropriate directories Before you begin using your secure server however you must generate your own key and obtain a certificate which correctly identifies your server You need a key and a certificate to operate your secure server which means that you can either gen erate a self signed certificate or purchase a CA signed certificate from a CA What are the differences between the two A CA signed certificate provides two important capabilities for your server Chapter 27 Apache HTTP Secure Server Configuration 207 Browsers usually automatically recognize the certificate and allow a secure connection to be made without prompting the user When a CA issues a signed certificate they are guaranteeing the identity of the organization that is providing the webpages to the browser If
447. your secure server is being accessed by the public at large your secure server needs a certificate signed by a CA so that people who visit your website know that the website is owned by the organiza tion who claims to own it Before signing a certificate a CA verifies that the organization requesting the certificate was actually who they claimed to be Most Web browsers that support SSL have a list of CAs whose certificates they automatically accept If a browser encounters a certificate whose authorizing CA is not in the list the browser asks the user to either accept or decline the connection You can generate a self signed certificate for your secure server but be aware that a self signed cer tificate does not provide the same functionality as a CA signed certificate A self signed certificate is not automatically recognized by most Web browsers and a self signed certificate does not provide any guarantee concerning the identity of the organization that is providing the website A CA signed certificate provides both of these important capabilities for a secure server If your secure server is to be used in a production environment you probably need a CA signed certificate The process of getting a certificate from a CA is fairly easy A quick overview is as follows 1 Create an encryption private and public key pair 2 Create a certificate request based on the public key The certificate request contains information about your server and
448. ystem 1 1 Features of ext3 The ext3 file system is essentially an enhanced version of the ext2 file system These improvements provide the following advantages Availability After an unexpected power failure or system crash also called an unclean system shutdown each mounted ext2 file system on the machine must be checked for consistency by the e2fsck program This is a time consuming process that can delay system boot time significantly espe cially with large volumes containing a large number of files During this time any data on the volumes is unreachable The journaling provided by the ext3 file system means that this sort of file system check is no longer necessary after an unclean system shutdown The only time a consistency check occurs using ext3 is in certain rare hardware failure cases such as hard drive failures The time to recover an ext3 file system after an unclean system shutdown does not depend on the size of the file system or the number of files rather it depends on the size of the journal used to maintain consistency The default journal size takes about a second to recover depending on the speed of the hardware Data Integrity The ext3 file system provides stronger data integrity in the event that an unclean system shutdown occurs The ext3 file system allows you to choose the type and level of protection that your data receives By default the ext3 volumes are configured to keep a high level of data consiste
449. ystem information Refer to the Red Hat Enterprise Linux Reference Guide for additional information about the proc directory 42 5 2 Related Books Red Hat Enterprise Linux Introduction to System Administration Red Hat Inc Includes a chap ter on monitoring resources redhat Chapter 43 OProfile OProfile is a low overhead system wide performance monitoring tool It uses the performance mon itoring hardware on the processor to retrieve information about the kernel and executables on the system such as when memory is referenced the number of L2 cache requests and the number of hardware interrupts received On a Red Hat Enterprise Linux system the oprofile RPM package must be installed to use this tool Many processors include dedicated performance monitoring hardware This hardware makes it possi ble to detect when certain events happen such as the requested data not being in cache The hardware normally takes the form of one or more counters that are incremented each time an event takes place When the counter value rolls over an interrupt is generated making it possible to control the amount of detail and therefore overhead produced by performance monitoring OProfile uses this hardware or a timer based substitute in cases where performance monitoring hard ware is not present to collect samples of performance related data each time a counter generates an interrupt These samples are periodically written out to d

Red Hat Enterprise Linux 3 System Administration Guide

Contents

Download Pdf Manuals

Related Search

Related Contents