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Red Hat Linux 8.0 The Official Red Hat Linux Customization Guide

1. Active Profile Home e New Rename Remove Devices Hardware Hosts DNS WE You may configure network devices associated with oj physical hardware here Multiple logical devices can be associated with a single piece of hardware Profile Status Device Nickname Type Add Active etho etho eme dit Active ethO eth0_office Ethemet H v Active fetho ethOhome Ethemet Copy Delete Activate z al gt Deactivate Guelp Apply X Close Figure 11 18 Home Profile You can also configure ethO to activate in the Office profile only and only activate a ppp modem device in the Home profile Another example is to have the Common profile activate ethO and an Away profile activate a ppp device for use while traveling Chapter 11 Network Configuration 103 A profile can not be activated at boot time Only the devices in the Common profile which are set to activate at boot time are activated at boot time After the system as booted execute the following command to enable a profile replace lt profilename gt with the name of the profile redhat config network cmd profile lt profilename gt 11 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 fol
2. Main Virtual Hosts Server Performance Tuning Lock File varflock httpd lock Browse PID File var runyhttpd pid v Browse Core Dump Directory etc httpd v Browse User apache Group apache Pox X Cancel g Heip Figure 18 10 Server Configuration 154 Chapter 18 Apache HTTP 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_LFCNTL_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 root 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 Server Root 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 writab
3. Active Profile Common ej New Devices Hardware Hosts DNS JUE You may configure network devices associated with 4 o physical hardware here Multiple logical devices can be associated with a single piece of hardware Profile Status Device Nickname Type Add v acie 9 9 aanp Edit Copy Delete Activate 7 B hHep v Apply X close Figure 11 10 Token Ring Device Be sure to click Apply to save the changes 97 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 as seen by its Inactive status To activate the device select it from the device list and click the Activate button 11 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 Device cipcbo Tunnel through Device None Server Mode Local Port 7777 Remote Peer Address Server Mode Remote Peer Port Remote Virtual Address Local Virtual Address Secret Key Configuration for your remote par
4. Figure 18 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 18 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 18 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 DocumentRoot directive within the VirtualHost directive Before Red Hat Linux 7 the Apache HTTP Server provided with Red Hat Linux used home httpd html as the DocumentRoot In Red Hat Linux 8 0 however 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
5. Figure 9 1 Creating a New RAID Partition 5 For Allowable Drives select the drive s on which RAID will be created If you have multiple drives all drives will be selected here and you must deselect those drives which will not have the RAID array on them 6 Enter the size that you want the partition to be 7 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 80 Chapter 9 Software RAID Configuration 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 space on the disk 8 Select Force to be a primary partition if you want the partition to be a primary partition 9 Select Check for bad blocks if you want the installation program to check for bad blocks on the hard drive before formatting it 10 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 Select the RAID button on the Disk Druid main partitioning screen see Figure 9 3 2 Next Figure 9 2 will appear where you
6. Delete up Down Search Domain Add 8 Heip Y Apply X Close Figure 11 15 DNS Configuration Chapter 11 Network Configuration 101 rote The name servers section does not configure the system to be a name server If the DNS server names are retrieved from DHCP or retrieved from the ISP of a modem connection do not add primary secondary or tertiary DNS servers 11 11 Activating Devices Network devices can be configured to activate at boot time or not to start 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 Red Hat Control Network 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 redhat control network provides an easy to use interface for configuring N activating and monitoring any type of network configuration The following network interfaces are configured on the system Status Device Nickname Activate K Active etho etho Configure X Close Figure 11 16 Activating Devices To activate a device select it from the list and click the Activate button To stop the device select it from the
7. 7 I Deactivate 8 Heip Y Apply X Close Figure 11 19 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 104 etho eth0 1 lo Chapter 11 Network Configuration 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 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 Link encap Local Loopback inet addr 127 0 0 1 Mask 255 0 0 0 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 3 redhat Chapter 12 Basic Firewall Configur
8. amp Cancel Pox Figure 15 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 inse cure_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 It the entire file system is exported selecting to disable subtree checking can increase the transfer rate This option corresponds to no_subt ree_check 128 Chapter 15 Network File System NFS Sync write operations on request Enabled by default this option does not allow the server to reply to requests before 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 The User Access tab allows the following options to be configured Treat remote root user as local ro
9. Select the groups that you want the user to be a member of and the user s primary group 24 3 Adding a New Group To add a new user group click the New Group button A window similar to Figure 24 4 will appear 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 Linux reserves group IDs lower than 500 for system groups Click OK to create the group The new group will appear in the group list Group Name mygroup Specify group ID manually GID 500 amp Cancel Bok Figure 24 4 New Group To add users to the group refer to Section 24 4 24 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 pull down menu A window similar to Figure 24 3 will appear 188 Chapter 24 User and Group Configuration Group Data Group Users Group Name mygroup amp Cancel ok Figure 24 5 Group Properties The Group Users tab displays which users are members of the group Select additional users to add them to the group and unselect users to remove from the group Click OK or Apply to modify the users in the group redhat Chapter 25 Gathering System Information Before you learn how to configure your system
10. If you choose High your system will not accept connections other than the default settings that are not explicitly defined by you By default only the following connections are allowed DNS replies 106 Chapter 12 Basic Firewall Configuration DHCP so any network interfaces that use DHCP can be properly configured If you choose High your firewall will not allow the following Active mode FTP passive mode FTP used by default in most clients should still work IRC DCC file transfers e RealAudio Remote X Window System clients If you are connecting your system to the Internet but do not plan to run a server this is the safest choice If additional services are needed you can choose Customize to allow specific services through the firewall ote If you select a medium or high firewall network authentication methods NIS and LDAP will not work Medium If you choose Medium your firewall will not allow remote machines to have access to certain resources on your system By default access to the following resources are not allowed e Ports lower than 1023 the standard reserved ports used by most system services such as FTP SSH telnet HTTP and NIS The NFS server port 2049 NFS is disabled for both remote severs and local clients The local X Window System display for remote X clients The X Font server port by default xfs does not listen on the network it is disabled in the font
11. As you can see from 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 directories on an hourly daily weekly or monthly basis respectively The files in these directory 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 27 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 27 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 dire
12. See GNOME Lokkit floppy group use of 182 free 191 ftp 119 G GNOME Lokkit activating the firewall 110 basic firewall configuration 108 configuring common services 110 DHCP 109 iptables service 111 local hosts 109 mail relay 111 GNOME System Monitor 190 gnome lokkit See GNOME Lokkit gnome system monitor 190 Gnu Privacy Guard See GnuPG GnuPG additional resources 267 checking RPM package signatures 241 digital signatures 267 exporting public key 264 to keyserver 265 generating a keypair 262 generating a revocation certificate 263 importing a public key 266 insecure memory warning 261 introduction 261 GPG See GnuPG group configuration adding groups 187 filtering list of groups 185 modify groups for a user 186 modify users in groups 188 modifying group properties 187 viewing list of groups 185 groups See group configuration floppy use of 182 H hardware viewing 194 Hardware Browser 194 Hardware RAID See RAID HTTP Configuration Tool directives See HTTP directives error log 146 modules 143 transfer log 146 HTTP directives DirectoryIndex 145 ErrorDocument 145 ErrorLog 147 Group 154 HostnameLookups 147 KeepAlive 155 KeepAliveTimeout 155 Listen 144 LogFormat 147 LogLevel 147 MaxClients 155 MaxKeepAliveRequests 155 Options 145 ServerAdmin 144 ServerName 144 TimeOut 155 TransferLog 146 User 154 httpd 143 hwbrowser 194 infor
13. sbin 1ilo If you did not have an entry for an older kernel in 1ilo conf you had a problem If you would like to know a solution to this problem read this section In many cases you can boot your Red Hat Linux system from the Red Hat Linux boot disk with your root filesystem mounted and ready to go Here is how to do it Enter the following command at the boot disk s boot prompt linux single root dev hdxx initrd Replace the xx in dev hdxx with the appropriate letter and number for your root partition What does this command do First it starts the boot process in single user mode with the root parti tion set to your root partition The empty initrd specification bypasses the installation related image on the boot disk which will cause you to enter single user mode immediately Is there a negative side to using this technique Unfortunately yes Because the kernel on the Red Hat Linux boot disk only has support for IDE built in if your system is SCSI based you will not be able to do this In that case you will have to access rescue mode using the linux rescue command mentioned above 1 To create an installation boot diskette insert a blank floppy disk and use the images boot img file on the Red Hat Linux CD ROM 1 with the command dd if boot img of dev fd0 3 redhat Chapter 9 Software RAID Configuration Read Chapter 3 first to learn about RAID the differences between Hardware and Software RAID and the diffe
14. 12 1 Security Level Configuration Tool 0 0 00 cece cece eeeeeeeeeeeeeneees 105 12 2 GNOME Lokkit 12 3 Activating the iptables Sefvitenee senaisiais iiie iiaii ia 111 13 Controlling Access to Services 0 ccccssevssovevedeccssivescustetsasssovesplavecsaveesbeeceuessedansevouanteseeess 113 13 1 Runlevels 113 13 2 TCP Wrappers 13 3 Services Configuration Tool 13 4 MESYSV oo eee 116 13 5 chkconfig 13 6 Additional ResOurces i viscose cine ds canines EE S EREE ERE EAE 117 14 OpenSSH aere e E EE E EEA GENE EE EE teases avers E EE 14 1 Why Use OpenSSH 0 0 14 2 Configuring an OpenSSH Server eee cseeeeseeeseseseeeeesessesssseeteeaeaes 14 3 Configuring an OpenSSH Client cee eseceescsescscseeeeesesseesseeeseaeaes 14 4 Additional Resources 15 Network File System NFS 15 1 Why Use NFS 15 2 Mounting NFS File Systems 15 3 Exporting NFS File Systems 15 4 Additional Resources 16 1 Why Use Samba 16 2 Configuring Samba cocasse a n a eis 16 3 Connecting to a Samba Share esssesesseresssseeseeresroreseeresrereveesevreseseesesresrerereeres 16 4 Additional Resources 17 Dynamic Host Configuration Protocol DHCP uu ees ceee eects eeeeseeseneneeesseeneeees 135 17 Ai WHy Use DHCP A noa Ra TRE AA S 135 17 2 Configuring a DHCP Server 17 3 Configuring a DHCP Client 17 4 Additional Resources 18 Apache HTT
15. Chapter 1 The ext3 File System 17 sbin e2fsck y dev hdb1 Then mount the partition again as ext2 file system by typing mount t ext2 dev hdbl1 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 18 Chapter 1 The ext3 File System 3 redhat Chapter 2 Swap Space 2 1 What is Swap Space Swap space in Linux is used when the amount of physical memory 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
16. Co writer Co maintainer of the Official Red Hat Linux Security Guide 278
17. Current Time 23 13 26 1 23 4 8 6 Hour 23 7 8 9 10 12 13 14 15 16 17 18 19 20 Minute 11 4 21 22 23 24 BS 2 2 28 29 3 3 Second 21 2 Network Time Protocol Your computer can synchronize its clock with a remote time server using the Network Time Protocol C Enable Network Time Protocol Server v Hep ij X Cancel OK Figure 23 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 will not take place until you click the OK button To change the time use the up and down arrow buttons beside the Hour Minute and Second in the Time section Changes will not take place until you click the OK button 184 Chapter 23 Time and Date Configuration ote Changing the date and time will change the system clock as well as the hardware clock Clicking OK is equivalent to executing the date and hwclock commands with the selected date and time 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 a NTP daemon to synchro nize your system clock with a remote server To enable this feature click the Enable Network Time Protocol button This will enable the Server pulldown menu You can choose on
18. REMOTE HOST IDENTIFICATION HAS CHANGED CC AAEEEAAEEEAAEEEEAEEEEEAEEEEEEEEEEEEEEEEEEEEAEEEEEREEEEEEE 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 120 Chapter 14 OpenSSH 14 3 Configuring an OpenSSH Client To connect to an OpenSSH server from a client machine you must have the openssh clients and openssh packages installed on the client machine 14 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 pengu
19. 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 will need to type in the text command at the boot prompt Additionally we use several different strategies to draw your attention to certain pieces of information In order of how critical the information is to your system these items will be marked as note tip important caution or a warning For example ote Remember that Linux is case sensitive In other words a rose is not a ROSE is not a rOsE rip The directory usr share doc contains additional documentation for packages installed on your system Ons If you modify the DHCP configuration file the changes will not take effect until you restart the DHCP daemon Efon Do not perform routine tasks as root use a regular user account unless you need to use the root account for system administration tasks Introduction xi warning If you choose not to partition manually a server installation will remove all existing partitions on all installed hard drives Do not choose this installation class unless you are sure you have no data you need to save 3 More to Come The Official Red Hat Linux Customization Guide is part of Red Hat s growing commitment to provide useful and timely support to Red Hat Linux users As
20. 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 init rd 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 ext3 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
21. and add a line like lt console gt 0600 lt scanner gt 0600 root Then when you log in at the console you will be given ownership of the dev scanner device and the permissions will be 0600 readable and writable by you only When you log out the device will be owned by root and still have 0600 now readable and writable by root only permissions 22 6 Enabling Console Access for Other Applications If you wish to make other applications accessible to console users you will have to do a bit more work 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 asr bin consolehelper application cd usr bin ln s consolehelper foo 2 Create the file etc security console apps foo touch etc security 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 you run usr bin foo it will call consolehelper which will authenticate the user with the help of usr sbin userhelper To authenticate the user consolehelper will ask for the user s password if etc pam d foo is acopy
22. cached 719 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 192 Chapter 25 Gathering System Information File Edit View Help Process Listing CPU Usage History EE CPU Used 3 50 Memory Swap Usage History ll Memory Used 710 MB Total 1006 MB Swap Used Obytes Total 1 9GB Devices Name Directory Used Space Total Space i i dev hda1 boot 22 3 MB 98 7 MB dev hda2 4 0 GB 18 6 GB Figure 25 2 GNOME System Monitor 25 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 h argument stands for human readable format The output looks similar to the following Filesystem Size Used Avail Use Moun
23. choose the time zone to use for the system Enter the desired root password for the system in the Root Password text entry box If you want to save the password as an encrypted password in the file select Encrypt root password When the file is saved the plaintext 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 To install languages in addition to the one selected from the Language pulldown menu check them in the Language Support list The language selected from the 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 will 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 check the Perform installation in text mode button You can perform a kickstart installation in interactive mode This means that the installation program will use all the options pre configured in the kickstart file but it will allow you to preview the options in each screen before you can continue to the next screen To continue to the next screen click the Next button after you have approved the settings If you are not satisfied with the pre configured options you can cha
24. daemon Name and Aliases Queue Type Driver Driver Options Queue Name test Aliases Add Edit Delete Tp Pox X cancel Figure 26 14 Editing a Printer 26 8 1 Names and Aliases If you want to rename a printer change the value of Queue Name in the Names and Aliases 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 A printer alias is an alternate name for a printer To add an alias for an existing printer click the Add button in the Name and Aliases tab enter the name of the alias and click OK Click OK again to return to the main window Click Apply to save the aliases and restart the printer daemon A printer can have more than one alias Chapter 26 Printer Configuration 209 26 8 2 Queue Type The Queue Type tab shows queue type that you selected when adding the printer and its settings You can change the queue type of the printer or just change the settings After making modifications click OK to return to the main window Click Apply to save the change and restart the printer daemon Depending on which queue type you choose you will see different different options Refer to the appropriate section on adding a printer for a description of the options 26 8 3 Driver The Driver tab shows which print driver is currently being used This is the same list that y
25. dependency Find this package on the Red Hat Linux CD ROMs or from the Red Hat FTP site or mirror and add it to the command rpm ivh foo 1 0 1 i386 rpm bar 2 0 20 3 1386 rpm If installation of both packages is successful you will see Preparing AEE AE AEAEE AE AE AE AE AE AE AE AE aE AE AE AE aE AE ARE AEA AP AE EAE aE AEE aE HEE HE aE EAE 1005 1 fo00 FEAE AE AE E AE AE AE ARE AE AEE AE E AE AEE AE EAE HE EAE HE EE aE AEE aE aE A EE HEE AEC 505 2 bar HARA AE AE E AE AE AE ARE E AEE aE AEE AEE AE AEE AE AEE HE EAE HE AEE HE aE 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 name of the package will be displayed bar 2 0 20 3 1386 rpm If you want to force the installation anyway a bad idea since the package probably will not run correctly use the nodeps option 31 2 3 Uninstalling Uninstalling a package is just as simple as installing one Type the following command at a shell prompt rpm e foo rote Notice that we used the package name foo not the name of the original package file foo 1 0 1 i386 rpm To uninstall a package you will need to replace foo with the actual package name of the orig
26. 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 6 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 rote 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 file has not been completed when the installation executes the s
27. per inode Number specified represents the number of bytes per inode on the filesystem when it is created It must be given in decimal format This option is useful for applications where you want to increase the number of inodes on the filesystem type replaced by fstype This option is no longer available Use fstype fstype Sets the filesystem 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 with start badblocks Specifies that the partition should be checked for bad sectors ote 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 lt mntpoint gt Location where the RAID filesystem 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 50 Chap
28. 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 To filter the contents of the log file for keywords type the word or words you are looking for the Filter for text field and click Filter Click Reset to reset the contents You can also change where the application looks for the log files from the Log Files tab Select the log file from the list and click the Change Location button Type the new location of the log file or click the 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 Log Files Alerts Log Files x Configure the path and filename for each log file displayed Log File Location Boot Log Ivarflog boot log Cron Log Jvarflog cron dmesg Log vat log dmesg FTP Log Wwarflog xferlog Mail Log Wwarflog maillog Change Location Refresh Rate z Refresh log file every 30 seconds X Close Figure 28 2 Log File Locations 28 3 Examining Log Files Log Viewer can be configured to display an alert icon beside lines that contain key alert words To add alerts words select Edit gt Preferences from the pull down menu and click on the Alerts tab Chapter 28 Log Files 223 Click the Add button to add an alert word To delete an al
29. the Select Ethernet Adapter window appears rote The installation program usually detects supported Ethernet devices and prompts you to con figure them If you configured any Ethernet devices during the installation they will already appear in the hardware list on the Hardware tab Chapter 11 Network Configuration 95 Configure DSL connection E Select the ethernet device for this account Ethemet Device etho Intel EtherExpress F Enter the provider name for this account Provider Name Enter the login name for this account Login Name Enter the password for this account Password X Cancel Back Forward Figure 11 7 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 7 Click Forward 8 On the Create DSL Connection page click Apply After configuring the DSL connect it appears in the device list as shown in Figure 11 6 Active Profi
30. usr bin ssh agent HOME Xclients default 3 Select Main Menu Button on the Panel gt Extras gt 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 4 Log out and then log back into GNOME in other words 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 14 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 14 3 4 4 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 124 Chapter 14 OpenSSH terminal wind
31. 0 68 3 srce rpm Size 619097 License GPL Packager Red Hat lt http bugzilla redhat com bugzilla gt Summary The Red Hat Linux sound configuration tool Description Sndconfig is a text based tool that sets up the configuration files you will need to use a sound card with a Red Hat Linux system Sndconfig can be used to set the proper sound type for programs that use the dev dsp dev audio and dev mixer devices The sound settings are saved by the aumix and sysV runlevel scripts 244 Chapter 31 Package Management with RPM Perhaps you now want to see what files the sndconfig RPM installs You would enter the follow ing rpm qlp sndconfig 0 68 3 i386 rpm The output will look like the following sbin sndconfig usr sbin sndconfig usr share locale bs LC_MESSAGES sndconfig mo usr share locale cs LC_MESSAGES sndconfig mo asr share locale da LC_MESSAGES sndconfig mo usr share locale de LC_MESSAGES sndconfig mo usr share locale es LC_MESSAGES sndconfig mo usr share locale eu_ES LC_MESSAGES sndconfig mo usr share locale fi LC_MESSAGES sndconfig mo asr share locale fr LC_MESSAGES sndconfig mo asr share locale gl LC_MESSAGES sndconfig mo asr share locale hu LC_MESSAGES sndconfig mo usr share locale id LC_MESSAGES sndconfig mo usr share locale is LC_MESSAGES sndconfig mo asr share locale it LC_MESSAGES sndconfig mo asr share locale ja LC_MESSAGES sndconfig mo usr share locale ko LC_MESSAGES sndconfig mo usr
32. 2 0 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 and ftp for transferring 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 with RSA authentication The openssh askpass gnome package contains a GNOME GUI desktop environment dialog window which is displayed when OpenSSH programs prompt for a password 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 if you want to allow SSH clients to connect to your host The openssh clients package contains the client programs needed to make encrypted con nections to SSH servers including the following ssh a secure replacement for rsh and slo gin a secure replaceme
33. 7 GNU Linux Comment For info see http www gnupg org mQGiBDkHP3URBACKWGsYh43pkxU9wj X1G67K8 DSr185r7dNtHNfLL ewil10k2 q8saWIn26QZPsDVqdUIMOdHfI6kQTAt9NzQbgceVrxLYNfgeBsvkHF POtnYcZRgL tZ6syBBWs8JB4xt 5VO9iJ SGAMPUQE8J pdn2aRXPApdoDw17 9LM8Rg6r gwCg5ZZa pGN1kgFu24WMSwC1zg4QTbMD 3MJCSx L99Ek SHXcB3yh j oOLmIrGAVBgoWdrkd BIGJQQFhV1NSwC8YhN 4nGHWpaTxgE tnb4CI 1wI G3DK901YMyRJ inkGJ6XYfP3b cCQmgATDF SuglAmddi tnw7deXqn eavaMxRXJM RQSgJJyVpbAO20qKe6L6Inb5SH kjcZA 9obTm499dDMRQ CNR92FA5prOzriy ziLUow cqI 59nt bEb9nY1mfmUNG6 SWOjCH pIQHSlerV EookyOyq3ocUdjeRYF d2j19xmeSyL2H3tDvnuE6vgqFU N sdvby4B2Iku7S hO6W6GPQAe pzdyX9vS Pnf80su7W3j60WprQkUGF 1bCBHYWxs YWdoZXIgPHBhdWxnYWxsQHJ 1ZGhhdC5jb20 iFYEEXECABYFA jkHP 3UECWOEAWMV AWIDF gI BAheAAAOJEJECmvGCPSWpMj QAONF 2zvRgdR 8or9pBhu95zeSnkb7AKCm UXVSOaSKON7J61 1VEwx11poLkBDQQ5Bz MEAQA8ztcWRJ jW8cHCgLaE402jyqQ 37gDT n4VS66nU YItzDFScVmgMuFRzhibLb1f09TpZzxEbSF3T6p9hLLnHCQ1bD HR SK fhOeTYMMgB3 HyUpNeqCMEEGSAnWD9P4rQt07 Pes38sVO1XOOSvsTyMGSWEB VSNZk R1 phA55r1s8cAAWUEAJ jqazvkObgFrw10PG9m7 fEeD1vPSV6HSAOfvz4w c7ckfpuxg URQNE3TIAOOAcprk8Gg8J 2CtebAyR sPSIsrk5111uGdk 10M85FpT cen20dJ tToAF 6 GnIkeCeP105aWIbDgdAUHBRykpdWU3GJ 7NS6923fVg SkhQWg uwrAiEYEGBECAAYFA jkHP4wACgkQkQKa8YI9J amliwCfXox Hj lorMKnQRIkeBcZ iLyPH1QA0133F t OHBqLtqdtP4vwyQRbibjw my Figure B 1 Copying Your Public Key Note that if you are submitting your key to another Web based keyserver the above transaction will b
34. 7 user 0 5 system 0 0 nice 96 6 idle Mem 256812K av 252016K used 4796K free 97228K shrd 43300K buff Swap 265032K av 1328K used 263704K free 86180K cached PID USER PRI NI SIZE RSS SHARE STAT CPU SMEM TIME COMMAND 15775 joe 5 0 11028 10M 3192 S 1 5 4 2 0 46 emacs 14429 root 15 0 63620 62M 3284 R 0 5 24 7 63 33 X 17372 joe 11 0 1056 1056 840 R 0 5 0 4 0 00 top 17356 joe 2 O 4104 4104 3244 S O33 2125 0 00 gnome terminal 14461 joe 1 0 3584 3584 2104 S 0 1 1 3 0 17 sawfish 1 root 0 0 544 544 476 S 0 0 0 2 0 06 init 2 root 0 0 0 0 0 SW 0 0 0 0 0 00 kflushd 3 root 1 0 0 0 0 SW 00 7 0 0 0 24 kupdate 4 root 0 0 0 0 0 SW 0 0 0 0 0 00 kpiod 5 root 0 0 0 0 0 SW 0 0 0 0 0 29 kswapd 347 root 0 0 556 556 460 S 0 0 0 2 0 00 syslogd 357 root 0 0 712 FALA 360 S 0 0 0 2 0 00 klogd 372 bin 0 0 692 692 584 S 0 0 0 2 0 00 portmap 388 root 0 0 0 0 0 SW 0 0 0 0 0 00 lockd 389 root 0 0 0 0 0 SW 0 0 0 0 0 00 rpciod 414 root 0 0 436 432 372 0 0 0 1 0 00 apmd 476 root 0 0 592 592 496 S 0 0 0 2 0 00 automount To exit top press the q key Useful interactive commands that you can use with t op include the following 190 Chapter 25 Gathering System Information Description Space Immediately refresh the display Display a help sereen Kill a process You will be prompted for the process ID and the signal to send to it Sort by memory usage Sort by CPU usage Table 25 1 Interactive top commands i n Change the number of processes
35. Additional Size Options Eixed size Fill all space up to MB Fill to maximum allowable size Force to be a primary partition Check for bad blocks X cancel Box Figure 10 1 Creating a Physical Volume 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 here and you must deselect all but one drive 6 Enter the size that you want the physical volume to be 84 Chapter 10 LVM Configuration 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 Select Check for bad blocks if you want the installation program to check for bad blocks on the hard drive before formatting it 10 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 7 N The boot partition can not be on a volume group be
36. DHCP to activate any Ethernet interfaces on the system you must say Yes to the DHCP question If you say no you will not be able to establish a connect using the Ethernet interface Many cable and DSL Internet providers require you to use DHCP to establish an Internet connection 110 Chapter 12 Basic Firewall Configuration Are you using DHCP on any of your interfaces If you are then say yes and the firewall rules will allow DHCP clients ta negotiate addresses with your provider A Yes No X Cancel Figure 12 4 DHCP 12 2 4 Configuring Services GNOME Lokkit also allows you to turn common services on and off If you answer Yes to configur ing services you are prompted about the following services Web Server Choose this option if you want people to connect to a Web server such as Apache running on your system You do not need to choose this option if you want to view pages on your own system or on other servers on the network Incoming Mail Choose this option if your system needs to accept incoming mail You do not need this option if you retrieve email using IMAP POP3 or fetchmail Secure Shell Secure Shell or SSH is a suite of tools for logging into and executing commands on a remote machine over an encrypted connection If you need to access your machine remotely through ssh select this option Telnet Telnet allows you to log into your machine remotely however it is not secure It sends
37. Linux system to use encrypted passwords If you choose to modify your registry you must do so for all your Windows NT or 2000 machines this is risky and may cause further conflicts To configure Samba on your Red Hat Linux system 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 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 To set each Samba user s password use the command replace username with each user s username smbpasswd username A Samba user account will not be active until a Samba password is set for it 4 Encrypted passwords must be enabled in the Samba configuration file In the file smb conf verify that the following lines are not commented out encrypt password yes smb passwd file etc samba smbpasswd 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 nt
38. Options High Partition Information O Medium Network Configuration Disabled Authentication Use default firewall rules Firewall Configuration Customize X Configuration Trusted device Package Selection Pre Installation Script Aow incoming Post installation Script Other ports 1029 tcp Figure 7 10 Firewall Configuration The Firewall Configuration window is identical to the screen in the Red Hat Linux installation program and the Security Level Configuration Tool with the same functionality Choose between High Medium and Disabled security levels Refer to Section 12 1 for detailed information about these security levels 7 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 button on the X Configuration window as shown in Figure 7 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 7 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 7 Kickstart Configurator 69 File Help Basic Configuration X Configuration Installation Method E Configure the X Wi
39. Project 15 4 3 Related Books Managing NFS and NIS Services by Hal Stern O Reilly amp Associates Inc 3 redhat Chapter 16 Samba Samba uses the SMB protocol to share files and printers across a network connection Operating systems that support this protocol include Microsoft Windows through its Network Neighborhood OS 2 and Linux 16 1 Why Use Samba Samba is useful if you have a network of both Windows and Linux machines Samba will allow files and printers to be shared by all the systems in your network If you want to share files between Red Hat Linux machines only refer to Chapter 15 If you want to share printers between Red Hat Linux machines only refer to Chapter 26 16 2 Configuring Samba Samba uses etc samba smb conf as its configuration file If you change this configuration file the changes will not take effect until you restart the Samba daemon with the command service smb restart The default configuration file smb conf in Red Hat Linux 8 0 allows users to view their Linux home directories as a Samba share on the Windows machine after they log in using the same username and password It also shares any printers configured for the Red Hat Linux system as Samba shared printers In other words you can attach a printer to your Red Hat Linux system and print to it from the Windows machines on your network To specify the Windows workgroup and description string edit the following lines in your smb
40. 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 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 a
41. and queue of your remote Ipd server If no queue is specified you will use the default queue on the remote server Select strict RFC1179 compliance if you are having problems connecting to an older Ipd server Server servername example com Queue p C Strict RFC1179 Compliance X amp Cancel Back Figure 26 6 Choosing the Printer Server The next step is to select the type of printer that is connected to the remote system Skip to Section 26 6 to continue 202 Chapter 26 Printer Configuration Oia The remote machine must be configured to allow the local machine to print on the desired queue As root create the file etc hosts 1lpa on the remote machine to which the printer is attached On separate lines in the file add the IP address or hostname of each machine which should have printing privileges 26 3 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 window shown in Figure 26 2 will appear Click Next to proceed You will see the screen shown in Figure 26 7 Enter a unique name for the printer in the Queue Name text field The printer name cannot contain spaces and must begin with a letter a through z or A through Z The valid characters are a through z A through Z O through 9 and _ Select Windows Printer from th
42. and then writes it for you in the file etc sysconfig iptables You should not try to use GNOME Lokkit to generate complex firewall rules It is intended for av erage users who want to protect themselves while using a modem cable or DSL Internet connection To configure specific firewall rules refer to the Firewalling with iptables chapter in the Official Red Hat Linux Reference Guide To disable specific services and deny specific hosts and users refer to Chapter 13 To start GNOME Lokkit type the command gnome lokkit at a shell prompt as root If you do not have the X Window System installed or if you prefer a text based program use the command lokkit to start the text mode version of GNOME Lokkit 12 2 1 Basic Basic Configuration Lokkit can set up either a low or high security configuration A high security configuration blocks all incoming accesses but requires you use specific fp configurations and blacks irc dcc The lower security option blocks system services but is not so intrusive A High Security more intrusive w Low Security less intrusive v Disable Firewall no protection lt j Back X Cancel Figure 12 2 Basic After starting the program choose the appropriate security level for your system High Security This option disables almost all network connects except DNS replies and DHCP so that network interfaces can be activated IRC ICQ and other instant messaging services as well as Real
43. answer Yes to kmod support and module version CONFIG_MODVERSIONS support during the configuration 6 After creating a usr src linux 2 4 config file use the command make dep to set up all the dependencies correctly 7 Use the command make clean to prepare the source tree for the build o0 It is recommended that you give the custom kernel you are building a modified version number so that you do not overwrite your existing kernel The method described here is the easiest to recover from in the event of a mishap If you are interested in other possibilities details can be found at http www redhat com mirrors LDP HOWTO 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 will allow you to have the old working kernel and the new kernel version 2 4 18 7 95custom on your system at the same time To give the kernel an unique name you can also append the date to the end of the string 9 Build the kernel with make bzImage 10 Build any modules you configured with make modules 11 Use the command make modules_instal1 to install the kernel modules even if you did not build any Make sure that you type the underscore _ This will install the kernel modules into the directory path 1lib modules KERNELVERSION kernel drivers where Appendix A Building a Custom Kernel 257 KERNELVERSION
44. append lt params gt Specifies kernel parameters linear Use the linear LILO option this is only for backwards compatibility and linear is now used by default nolinear Use the nolinear LILO option linear is now used by default location Specifies where the LILO boot record is written Valid values are the following mbr the default or part ition installs the boot loader on the first sector of the partition containing the kernel If no location is specified LILO is not installed lba32 Forces the use of lba32 mode instead of autodetecting 46 Chapter 6 Kickstart Installations lilocheck optional If 1ilocheck is present the installation program checks for LILO on the MBR of the first hard drive and reboots the system if it is found in this case no installation is performed This can prevent kickstart from reinstalling an already installed system logvol optional Create a logical volume for Logical Volume Management LVM with the syntax logvol mountpoint vgname name size size name name 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
45. as if the files were located on the client s local hard drive Red Hat 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 15 1 Why Use NFS NFS is useful for sharing directories of files between multiple users on the same network For example a 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 15 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 warning 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 fileserver 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 fil
46. be displayed Selected Device Floppy Disks Hard Drives Network devices System devices USB devices Video cards Device Information Manufacturer Unknown Driver ignore Device dev hde Figure 25 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 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 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 25 5 Additional Resources To learn more about gathering system information refer to the following resources Chapter 25 Gathering System Information 195 25 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
47. be given to the new queue optional If one is not given a name based on the device node such as lp0 will be used as default Set this as the default queue optional After adding the printer use the following command to start restart the printer daemon 1pd service lpd restart 26 10 2 Removing a Printer You can also remove a printer queue through the command line To remove a printer queue redhat config printer tui Xremove local options Options device node The device node used for example dev 1p0 Required make make The IEEE 1284 MANUFACTURER string or if none is available the printer manufacturer s name as in the foomatic database Required model model The IEEE 1284 MODEL string or if none is available the printer model as in the foomatic database Required After removing the printer from the Printer Configuration Tool configuration restart the printer daemon for the changes to take effect service lpd restart If you removed all printers and do not want to run the printer daemon anymore execute the following command service lpd stop 212 Chapter 26 Printer Configuration 26 11 Managing Your 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 e
48. boot time edit etc fstab to include swapfile swap swap defaults 0 0 The next time the system boots it will enable the new swap file 6 After adding the new swap file and enabling it make sure 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 8 for instructions on booting into rescue mode When prompted to mount the filesystem 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 or fdisk Only parted will be discussed To remove the partition with 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 Chapter 2 Swap Space 21 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 MIN
49. 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 13 for information on managing services 15 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 Chapter 15 Network File System NFS 127 To use the NFS Server Configuration Tool you must by running the X Window System To start the application select Main Menu Button on the Panel gt Server Settings gt NFS Server or type the command redhat config nfs Eile Help 8 v Add Propertie Delete Help Apply Directory Hosts Permissions tmp 192 168 100 Read Figure 15 1 NFS Server Configuration Tool To add an NFS share click the Add button The dialog box shown in Figure 15 2 will appear The Basic tab requires the following information e Directory Specify the directory to share such as tmp Host s Specify the host s to which to share the directory Refer to Section 15 3 2 for an expla nation 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 192 168 100 Basic permissions Read only Read Write
50. 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 Red Hat Linux 8 0 configures ext3 volumes to keep a high level of data consistency 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 See Section 1 3 for more on how to perform this task If you perform a fresh installation of Red Hat Linux 8 0 the default file system assigned to the system s Linux partitions is ext3 If you upgrade from a version of Red Hat Linux that uses ext2 partitions the installation program allows you to convert these partitions to e
51. details If you configured the Apache HTTP Server with the HTTP Configuration Tool in previous versions of Red Hat Linux and then performed an upgrade you can use it the application to migrate the config uration file to the new format for version 2 0 Start the HTTP Configuration 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 that are shipped with Red Hat Linux can be configured with HTTP Configuration Tool If additional modules are installed they can not be configured using this tool The HTTP Configuration Tool requires the X Window System and root access To start the appli cation go to the Main Menu Button gt Server Settings gt HTTP Server or type the command redhat config httpdat a shell prompt for example in an XTerm or GNOME Terminal Efon Do not edit the etc httpd conf httpd conf configuration file by hand if you wish to use this tool HTTP Configuration Tool generates this file after you save your changes and exit the program If you want to add additional modules or configuration
52. 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 you will see 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 31 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 will be upgraded to the newer version However RPM s freshen option will not install a package if no previously installed package of the same name exists This differs from RPM s upgrade option as an upgrade will 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 will do the job If you
53. expire 86400 ttl ns IN NS 1 2 3 4 After configuring the Forward Master Zone click OK to return to the main window as shown in Figure 20 1 From the pulldown menu choose File gt Apply 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 20 2 Adding a Reverse Master Zone To add a reverse master zone click the Add button and select Reverse Master Zone Enter the first three octets of the IP address range that you want to configure For example if you are configuring 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 will appear as shown in Figure 20 3 with the following options An A U N e oo IP Address The first three octets that you just entered in the previous window Reverse IP Address Non editable Pre populated based on the IP Address entered Contact Email address of the main contact for the master zone File Name File name of DNS database file in the var named directory 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 incre mented each time the file is changed so that the slave nameservers for the zone will retrieve th
54. for kickstart installations via a network as well as for the installed system This option is new to Red Hat Linux 8 0 Chapter 6 Kickstart Installations 47 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 to 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
55. 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 14 OpenSSH 121 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 transfer 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 14 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 using FTP Refer to the sftp man page for a list of these commands To read the man page execute the comma
56. hard drive Next we take a closer look at each of these scenarios 8 1 1 Unable to Boot Linux This problem is often caused by the installation of another operating system after you have installed Red Hat Linux Some other operating systems assume that you have no other operating systems on your computer and 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 Linux unless you can get into rescue mode 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 will 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 8 1 2 Hardware Software Problems This category includes a wide variety of different situations Two examples include failing hard drives and forgetting to run LILO after building a new kernel if you are using LILO as your boot loader If you are using GRUB you do not have to execute a command to reread the GRUB configuration file However if you specify an invalid root device or kernel in the GRUB configuration file you might not know until you reboot your computer
57. 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 2 Change the permissions of your ssh directory using the command chmod 755 ssh 3 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 does not exist you can copy the file ssh id_rsa pub to the file ssh authorized_keys on the other machine 4 If you are running GNOME skip to Section 14 3 4 4 If you are not running the X Window System skip to Section 14 3 4 5 14 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 1 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 rip 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 just a word The public key is written to ssh id_dsa pub The privat
58. 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 14 3 4 4 If you are not running GNOME skip to Section 14 3 4 5 14 3 4 4 Configuring ssh agent with GNOME The ssh agent 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 14 3 4 5 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 installed install it from your Red Hat Linux CD ROM set from a Red Hat FTP mirror site or using Red Hat Network 2 If you do not have an Xclients file run switchdesk to create it In your Xclients file find the following line exec HOME Xclients default Change the line so that it instead reads exec
59. 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 you will see the New Tab option that 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 will be shown like the following example Go to Main Menu Button on the Panel gt Programming gt Emacs to start the Emacs text editor button on a GUI screen or window This style indicates that the text will 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 When you see text in this style it indicates text displayed by the computer on the command line You will see responses to commands you typed in error messages and interactive prompts for your input during scripts or programs shown this way For example Use the 1s command to display the contents of a directory ls Desktop about html logs paulwesterberg png Mail backupfiles mail reports x Introduction 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 will be shown in this style Examples S stephen maturin stephen leopard login user input
60. installation This chapter explains these steps in detail 6 3 Creating the Kickstart File The kickstart file is a simple text file containing 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 Linux Documentation CD using the Kickstart Configurator application or writing it from scratch The Red Hat 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 ASCII 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 6 4 for a list of kickstart options You must include the required options The packages section Refer to Section 6 5 for details The pre and post sections These two sections can be in any order and are not required Refer to Section 6 6 and Section 6 7 for details 38 Chapter 6 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 t
61. it work e2label dev hda3 work By default the Red Hat Linux 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 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 will be mounted at boot time To mount the partition without rebooting as root type the command mount work 5 3 Removing a Partition warning 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 create the partition parted dev hda View the current partition table to determine the minor number of the partition to remove print Chapter 5 Managing Disk Storage 33 Remove the partition wit
62. key 162 Chapter 19 Apache HTTP Secure Server Configuration 19 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 generated 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 will display a message similar to the following umask 77 usr bin openssl genrsa des3 1024 gt etc httpd conf ssl key server key Generating RSA private key 1024 bit long modulus ESAR tt t ee a ee a ae ee ee ee ee ee ee a a a A ab ARE e is 65537 0x10001 Enter PEM pass phrase You now need to type in a password For best security your password should contain at least eight characters include numbers and or punctuation and not be a word in a dictionary Also remember that your password is case sensitive rote You will need to remember and enter this password every time you start your secure Web server so do not forget it You will be asked to re type the password to verify that it is correct Once you have typed it in correctly etc httpd conf ssl key server key containing your key will be created Note that if you do not want to type in a password every time you start your secure Web server you will need to use the following two commands
63. list and click Deactivate 11 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 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 can not 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 activated at the same time Refer to Section 11 13 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 By default there is one profile called Common To create a new profile click the New button in the Active Profile frame Enter a unique name for the profile After creating a new profile if all the devices are not listed for all the profiles add them by click the Add button If a device already exists for the physical device use the Copy button to copy the existing 102 Chapter 11 Network Configuration devic
64. list keys You will see something similar to the following home newuser gnupg pubring gpg pub 1024D B7085C8A 2000 06 18 Your Name lt you yourisp net gt sub 1024g E12AF9C4 2000 06 18 If you created a GnuPG key with version 1 0 6 or lower exported your private key and imported it into a new one you have to explicitly trust your own key to sign items with version 1 0 7 To trust your key type the following command replace lt user id gt gpg edit key lt user id gt At the Command gt prompt type trust and select 5 I trust ultimately to trust your own key B 4 Generating a Revocation Certificate Once you have created your keypair you should create a revocation certificate for your public key If you forget your passphrase or if it has been compromised you can publish this certificate to inform users that your public key should no longer be used 264 Appendix B Getting Started with Gnu Privacy Guard rote When you generate a revocation certificate you are not revoking the key you just created Instead you re giving yourself a safe way to revoke your key from public use Let s say you create a key then you forget your passphrase switch ISPs addresses or suffer a hard drive crash The revocation certificate can then be used to disqualify your public key Your signature will be valid to others who read your correspondence before your key is revoked and you will be able to decrypt messages received prior to its
65. 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 e 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 31 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 simple use of verifying is rpm V foo which verifies that all the files in the foo package are as they were when they were originally installed For example To verify a package containing a particular file rpm Vf bin vi e To verify ALL installed packages Chapter 31 Package Management with RPM 241 rpm Va e To verify an installed package against an RPM package file rpm Vp foo 1 0 1 1386 rpm This command can be useful if you suspect that your RPM databases are cor
66. 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 Official Red Hat Linux Customization Guide or if you have thought of a way to make this manual better we would love to hear from you Please submit a report in Bugzilla http www redhat com bugzilla against the component rhl cg Be sure to mention the manual s identifier rhl cg EN 8 0 Print RHI 2002 08 14T17 28 0400 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 official edition of Red Hat Linux 8 0 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 Official Red Hat Linux product you purchased e Official Red Hat support Get help with your installation questions from Red Hat Inc s support team e 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 Official Red Hat E Newsletter Every month get the latest news and product informat
67. nfs Install from the NFS server specified e server Server from which to install hostname or IP 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 be latin2 bg br abnt2 cf cz lat2 cz us qwertz de de latinl de latinl nodeadkeys dk dk latinl dvorak es et fi i latinl fry fr latind fr latinl fr pe frich fr CH latini gr hu hul01 is latinl it it ibm it2 jp106 no no latinl pl pt latinl ro ru ru cpl251 ru ms rul ru2 ru_win se latinl sg sg latinl sk qwerty slovene speakup speakup lt trq ua uk us lang required Sets the language to use during installation For e
68. one rip To learn more about the print drivers go to http Awww linuxprinting org printer_list cgi rip You can select a different print driver after adding a printer by starting Printer Configuration Tool selecting the printer from the list clicking Edit clicking the Driver tab selecting a different print driver and applying the changes Chapter 26 Printer Configuration 207 Select a Print Driver Select a print driver for your printer Printer a Vv Cascvere gt LaserJet 2 wPS gt LaserJet 2000 LaserJet 2100 gimp print gimp print ijs oi jSgray ljet4 omni gt LaserJet 2100M amp Cancel Back Figure 26 13 Selecting a Print Driver The print driver processes 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 to select a print driver to process the data that is sent to the printer If you are configuring a remote printer 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 will be filtered more than once and the data will be converted to a format that the printer can not understand To make sure the data is not filtered more than once first try selecting Raw Print Queue or Postscript Printer if you are configuring a remote printer After applying the changes
69. options e free manual page type man free to learn more about free and its many options e df manual page Type man df to learn more about the df command and its many options e du manual page Type man du to learn more about the du command and its many options e proc The contents of the proc directory can also be used to gather more detailed system information Refer to the Official Red Hat Linux Reference Guide for additional information about the proc directory 196 Chapter 25 Gathering System Information 3 redhat Chapter 26 Printer Configuration Printer Configuration Tool allows users to configure a printer in Red Hat Linux It helps maintain the etc printcap configuration file print spool directories and print filters Starting with version 8 0 Red Hat Linux ships with two printer systems Printer Configuration Tool configures the printing system called LPRng LPRng is also the default printing system This chapter focuses on using Printer Configuration Tool to configure LPRng For more information on the alternate printing system called CUPS refer to Section 26 12 To use Printer Configuration Tool you must have 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 You can also force Printer Configuration T
70. page on 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 26 13 2 Useful Websites http www linuxprinting org GNU Linux Printing contains a large amount information about printing in Linux http www cups org Documentation FAQs and newsgroups about CUPS redhat Chapter 27 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 Linux comes precon figured to run important system tasks to keep the system updated For example the slocate database used by the locate 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 Linux comes with four automated tasks utilities cron anacron at and batch 27 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 configure tasks based on time per
71. password configured type p and enter the password 2 Select Red Hat Linux with the version of the kernel that you wish to boot and type e for edit You will be presented with a list of items in the configuration file for the title you just selected 3 Select the line that starts with kernel and type e to edit the line 4 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 5 Back at the GRUB screen type b to boot into single user mode If you are using LILO specify one of these options 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 boot linux single boot linux emergency In single user mode your computer boots to runlevel 1 Your local filesystems will be mounted but your network will not be activated You will have a usable system maintenance shell 78 Chapter 8 Rescue Mode In emergency mode you are booted into the most minimal environment possible The root filesystem will be mounted read only and almost nothing will be set up The main advantage of emergency mode over linux single is that your init files are not loaded If init is corrupted or not working you can still mount filesystems to recover data that could be lost during a re installation Have you ever rebuilt a kernel and eager to try out your new handiwork rebooted before running
72. plain text including passwords over the network It is recommended that you use SSH to log into your machine remotely If you are required to have telnet access to your system select this option To disable other services that you do not need use Services Configuration Tool see Section 13 3 or ntsysv see Section 13 4 or chkconfig see Section 13 5 12 2 5 Activating the Firewall Clicking Finish will write the firewall rules to etc sysconfig iptables and start the firewall by starting the iptables service It is highly recommended that you run GNOME Lokkit from the machine not from a remote X session If you disable remote access to your system you will no longer be able to access it or disable the firewall rules Click Cancel if you do not want to write the firewall rules Chapter 12 Basic Firewall Configuration 111 12 2 5 1 Mail Relay A mail relay is a system that allows other systems to send email through it If your system is a mail relay someone can possibly use it to spam others from your machine If you chose to enable mail services after you click Finish on the Activate the Firewall page you will be prompted to check for mail relay If you choose Yes to check for mail relay GNOME Lokkit will attempt to connect to the Mail Abuse Prevention System website at http www mail abuse org and run a mail relay test program The results of the test will be displayed when it is finished If your system is open to mail re
73. print a test page to test this 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 26 6 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 to the etc printcap configura tion file and restart the printer daemon 1pd After applying the changes print a test page to ensure the configuration is correct Refer to Section 26 7 for details If you need to print characters beyond the basic ASCII set including those used for languages such as Japanese you need to go to your driver options and select Prerender Postscript Refer to Section 26 8 for details You can also configure options such as paper size if you edit the print queue after adding it 26 7 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 test from the printer list and 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 diffe
74. reach this percent capacity it will be reported For exam ple if defaultCutoff 90 an email will be sent when the monitored disk drives reach 90 capacity cutoff dev partition Override the defaultCutoff for the partition For example if cutoff dev hda3 50 is specified diskcheck will alert the system administrator when the partition dev hda3 reaches 50 capacity cutoff mountpoint Override the defaultCutoff for the mount point For example if cutoff home 50 is specified diskcheck will alert the system administrator when the mount point home reaches 50 capacity exclude Specify one or more partitions for diskcheck to ignore For example if exclude dev sda2 dev sda4 is specified diskcheck will not alert the system administrator if dev sda2 or dev sda4 reaches the specified cutoff percentage ignore Specify one or more file system types to ignore in the format x filesystem type For example if ignore x nfs x iso9660 is specified the system administrator will not be alerted about nfs or iso9660 file systems reaching capacity mailTo Email address of the system administrator to alert when partitions and mount points reach the specified capacity For example if mailTo webmaster example com is speci fied webmaster example com will be emailed alerts mailFrom Specify the identity of the email sender This is useful if the system administrator wants to f
75. 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 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 64 Chapter 7 Kickstart Configurator Mount Point v File System Type ext3 v Size MB 1 s Additional Size Options Fixed size Grow to maximum of MB 1 s Fill all unused space on disk Use recommended swap size C Force to be a primary partition asprimary Make partition on specific drive ondisk Drive for example hda or sdc Use existing partition onpart Partition for example hdal or sdc3 Format partition X Cancel Pox Figure 7 5 Creating Partitions To edit an existing partition select the partition from the list and click the Edit button The same Partitions Options window that appears when you add a partition appears except it contains the valu
76. share locale no LC_MESSAGES sndconfig mo asr share locale p1 LC_MESSAGES sndconfig mo asr share locale pt LC_MESSAGES sndconfig mo usr share locale pt_BR LC_MESSAGES sndconfig mo asr share locale ro LC_MESSAGES sndconfig mo usr share locale ru LC_MESSAGES sndconfig mo asr share locale sk LC_MESSAGES sndconfig mo usr share locale sl1 LC_MESSAGES sndconfig mo usr share locale sr LC_MESSAGES sndconfig mo usr share locale sv LC_MESSAGES sndconfig mo asr share locale tr LC_MESSAGES sndconfig mo usr share locale uk LC_MESSAGES sndconfig mo usr share locale wa LC_MESSAGES sndconfig mo usr share locale zh LC_MESSAGES sndconfig mo usr share locale zh_CN GB2312 LC_MESSAGES sndconfig mo usr share locale zh_TW Big5 LC_MESSAGES sndconfig mo usr share locale zh_TW LC_MESSAGES sndconfig mo usr share man man8 sndconfig 8 gz usr share sndconfig usr share sndconfig sample au usr share sndconfig sample midi usr share sndconfig sample2 au These are just a few examples As you use it you will find many more uses for RPM 31 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 31 5 1 Installed Documentation rpm help This command displays a quick reference of RPM parameters man rpm The RPM man page will give you more detail about RPM parameters than the rpm help co
77. shown in Figure 9 3 At this point you can continue with your installation process Refer to the Official Red Hat Linux Installation Guide for further instructions Online Help Disk Setup Choose where you would like Red Hat Linux to be installed If you 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 used fdisk to partition you must define mount points for your partitions Use the Edit button once you have selected Ss Hide Help O Release Notes gt Partitioning Drive dev hda Geom 2482 255 653 Model Maxtor 52049H3 ix hda2 jhda3 hda5 pass m8 2996 Me 374 ME Drive dev hdb Geom 2482 255 653 Model Maxtor 52049H3 hdb1 jhdb2 Free 4000 MB 2047 me 13421 mB New Em Delete Reset RAID LM Mount Point Size la Device RAID Volume Type Format yp Start a dev mdo home ext3 5993 Hard Drives dev hda ldev hda1 boot ext3 v 12 1 13 dev hda2 dev mdo software RAID Idev hda3 idevimd0 software RAID dev hdad Extended k ih ie C Hide RAID device LVM Volume Group members _Back Next Fi
78. 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 sometimes that is not easy 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 easiest way to achieve this it to boot your system in rescue mode Refer to Chapter 8 for instructions on booting into rescue mode When prompted to mount the filesystem 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 or fdisk Using parted is easier than fdisk thus only parted will be explained To create a swap partition with parted Ata 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 mu
79. the certificate request The display with example responses will look like this 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 164 Chapter 19 Apache HTTP Secure Server Configuration State or Province Name full name Berkshire North Carolina Locality Name eg city Newbury Raleigh Organization Name eg company 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 You will have to type in the rest of the inputs State or Province Name Locality Name Or gan
80. 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 11 12 configure the ESSID mode frequency channel transmit rate and key for your wireless device Configure Wireless Connection F Mode Auto Network Name SSID Auto O Specified Channel 1 4 Transmit Rate Auto x Key X Cancel Back Forward Figure 11 12 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 11 13 Chapter 11 Network Configuration 99 Active Profile Common z New Devices Hardware Hosts DNS 4 You may configure network devices associated with 4 Oo physical hardware here Multiple logical devices can be i associated with a single piece of hardware Profile Status Device Nickname iv
81. 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 there is no dhcpd leases file that is required to start the service Do not create a new lease file if this occurs If you do all the old leases will be lost and cause many problems The correct solution is to rename the dhcpd leases backup file to dhcpd leases and then start the daemon 17 2 3 Starting and Stopping the Server Osan Before you start the DHCP server for the first time it will fail unless there is an existing dhcpd leases file Use the command touch var lib dhcp dhcpd leases to create the file if it does not exist Chapter 17 Dynamic Host Configuration Protocol DHCP 139 To start the DHCP service use the command sbin service dhcpd start To stop the DHCP server use the command sbin service dhcpd stop If you want the daemon to start automati cally at boot time see Chapter 13 for information on how to manage services If you have more than one network interface attached to the system but you
82. 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 will retrieve the latest data The Bind 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 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 ns example com Serial Number 1 Set Time Settings Records forward example com Add R Edit Delete X Cancel ok Figure 20 2 Adding a Forward Master Zone The configuration shown in Figure 20 2 creates the following entry in etc named conf 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 Chapter 20 BIND Configuration 171 STTL 86400 IN SOA ns example com root localhost 2 serial 28800 refresh 7200 retry 604800
83. the paths to the kernel and init rd image are relative to the boot partition By default Red Hat Linux uses Red Hat Linux and the kernel version in parentheses to differentiate between different kernels for GRUB to boot In our example the new boot grub grub conf file created by the new kerne1l pkg script would look like the following NOTICE You have a boot partition This means that all kernel paths are relative to boot default 1 timeout 30 splashimage hd0 0 grub splash xpm gz title Red Hat Linux 2 4 18 7 95custom root hd0 0 kernel vmlinuz 2 4 18 7 95custom ro root dev hda3 initrd initrd 2 4 18 7 95custom img title Red Hat Linux 2 4 18 7 95 root hd0 0 kernel vmlinuz 2 4 18 7 95 ro root dev hda3 initrd initrd 2 4 18 7 95 img Notice that the default boot entry is set to 1 The script does not change the default kernel to boot it only adds a new section for the new kernel If the file is not modified correctly and you did not receive any error messages from make install add the new section manually After rebooting selecting the new kernel from the list and seeing that the new kernel works you can make your new kernel the default Either place its section first or change the default entry number to the appropriate number remember that it starts counting with 0 For GRUB you do not need to run any commands after modifying the configuration file A 3 2 LILO If you selected LILO as your boot loa
84. through the firewall Note during a workstation installation the majority of these services are not installed on the system DHCP If you allow incoming DHCP queries and replies you allow any network interface that uses DHCP to determine its IP address DHCP is normally enabled If DHCP is not enabled your computer can no longer get an IP address SSH Secure SHell SSH is a suite of tools for logging into and executing commands on a remote machine If you plan to use SSH tools to access your machine through a firewall enable this option You need to have the openssh server package installed in order to access your machine remotely using SSH tools Telnet Telnet is a protocol for logging into remote machines Telnet communications are unen crypted and provide no security from network snooping Allowing incoming Telnet access is not recommended If you do want to allow inbound Telnet access you will need to install the telnet server package 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 will need to install the apache package if you want to serve webpages Enabling WWW HTTP will not open a port for HTTPS To enable HTTPS specify it in the Other ports field Mail SMTP If you want to allow incoming mail delivery t
85. to a different UNIX system that can be accessed over a TCP IP network for example a printer attached to another Red Hat Linux system on your network In the main printer list as shown in Figure 26 1 the Queue Type for a remote UNIX printer is set to LPD Windows Printer 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 In the main printer list as shown in Figure 26 1 the Queue Type for a remote Windows printer is set to SMB Novell Printer NCP Queue a printer attached to a different system which uses Novell s Net Ware network technology In the main printer list as shown in Figure 26 1 the Queue Type for a remote Novell printer is set to NCP JetDirect Printer a printer connected directly to the network through HP JetDirect instead of to a computer In the main printer list as shown in Figure 26 1 the Queue Type for a JetDirect printer is set to JETDIRECT inai If you add a new print queue or modify an existing one you need to restart the printer daemon 1pa for the changes 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 etc printcap configuration file until the printer daemon 1pq is restarted Alternatively you can choose File gt Save Changes and then choose File gt Restart Ipd to save your changes a
86. two important capabilities for your server Browsers will 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 Web pages to the browser If your secure server is being accessed by the public at large your secure Web server needs a certifi cate signed by a CA so that people who visit your website know that the website is owned by the organization 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 will automatically accept If a browser encounters a certificate whose authorizing CA is not in the list the browser will ask the user to choose whether to accept or decline the connection You can generate a self signed certificate for your secure Web server but be aware that a self signed certificate will not provide the same functionality as a CA signed certificate A self signed certificate will not be automatically recognized by users 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 serv
87. ubr X Cancel Back _ Forward Figure 11 1 Ethernet Settings 7 Click Apply on the Create Ethernet Device page After configuring the Ethernet device it appears in the device list as shown in Figure 11 2 Chapter 11 Network Configuration 91 Active Profile Common e New Devices Hardware Hosts DNS You may configure network devices associated with 4 ol physical hardware here Multiple logical devices can be o associated with a single piece of hardware Profile Status Device Nickname Type Add iv Be ave eip ema ALG Edit copy Delete Activate L Ki gt 8 Heip Apply X Close Figure 11 2 Ethernet Device Be sure to click Apply 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 You can edit its configuration to modify this setting When the device is added it is not activated as seen by its Inactive status To activate the device select it from the device list and click the Activate button 11 3 Establishing an ISDN Connection An ISDN connection is an Internet connection established with a ISDN modem c
88. usually run by cron To use the Anacron service you must have the anacron RPM package installed and the anacron ser vice must be running To determine if the package is installed use the rpm q anacron command To determine if the service is running use the command sbin service anacron status 27 2 1 Configuring Anacron Tasks Anacron tasks are listed in the configuration file et c anacrontab Each line in the configuration file corresponds to a task and has the format period delay job identifier command period frequency in days to execute the command delay delay time in minutes job identifier description of the task used in Anacron messages and as the name of the job s timestamp file can contain any non blank characters except slashes command command to execute For each tasks Anacron determines if the task has been executed within the period specified in the period field of the configuration file If it has not been executed within the given period Anacron executes the command specified in the command field after waiting the number of minutes specified in the delay field After the task is completed Anacron records the date in a timestamp file in the var spool anacron directory Only the date is used not the time and the value of the job ident ifier is used as the filename for the timestamp file Environment variables such as SHELL and PATH can be defined at the top of etc anacrontab as
89. with the cron configuration file The default configuration file looks similar to the following etc anacrontab configuration file for anacron See anacron 8 and anacrontab 5 for details SHELL bin sh PATH usr local sbin usr local bin sbin bin usr sbin usr bin 218 Chapter 27 Automated Tasks These entries are useful for a Red Hat Linux system 1 5 cron daily run parts etc cron daily 7 10 cron weekly run parts etc cron weekly 30 S cron monthly run parts etc cron monthly Figure 27 1 Default anacrontab As you can see in Figure 27 1 anacron for Red Hat Linux is configured to make sure the daily weekly and monthly cron tasks are run 27 2 2 Starting and Stopping the Service To start the anacron service use the command sbin service anacron start To stop the ser vice use the command sbin service anacron stop It is recommended that you start the ser vice at boot time Refer to Chapter 13 for details on starting the anacron service automatically at boot time 27 3 At and Batch While cron and anacron are used to schedule recurring tasks the at command is used to schedule a one time task at a specific time The batch 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 you must have the at RPM package installed and the atd service must be running To determine if the package is installed use the rpm q at command To determine if
90. with the rpm command if you want to keep the old kernel If you use the u option to upgrade the kernel package it will overwrite the currently installed kernel the kernel version and x86 version might vary rpm ivh kernel 2 4 18 7 95 i386 rpm If the system is a multi processor system install the kerne1 smp packages as well the kernel version and x86 version might vary rpm ivh kernel smp 2 4 18 7 95 1386 rpm If the system is i686 based and contains more than 4 gigabytes of RAM install the kernel bigmem package built for the i686 architecture as well the kernel version might vary rpm ivh kernel bigmem 2 4 18 7 95 i686 rpm If you plan to upgrade the kernel source kernel docs or kernel utils packages you prob ably do not need to keep the older versions Use the following commands to upgrade these packages the versions might vary rpm Uvh kernel source 2 4 18 7 95 i1386 rpm rpm Uvh kernel docs 2 4 18 7 95 i386 rpm rpm Uvh kernel utils 2 4 18 7 95 1386 rpm 228 Chapter 29 Upgrading the Kernel If you are using PCMCIA for example a laptop you also need to install the kernel pemcia cs and keep the old version If you use the i switch it will probably return a conflict because the older kernel needs this package to boot with PCMCIA support To work around this use the force switch as follows the version might vary rpm ivh force kernel pcmcia cs 3 1 24 2 1386 rpm If you are using the ext3 file system
91. 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 Linux system using simple commands and a few simple programs 25 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 processes 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 t op s output is provided as follows 6 14pm up 2 days 19 29 5 users load average 0 10 0 06 0 07 71 processes 68 sleeping 2 running 1 zombie 0 stopped CPU states 2
92. your old key and certificate if you are changing your IP address or domain name Certificates are issued for a particular IP address and domain name pair You will need to get a new certificate if you are changing your IP address or domain name Ifyou 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 Web server However you will not be allowed to because VeriSign issues certificates for one particular server software and IP address domain name combination If you change either of those parameters for example if you previously used another secure Web server product and now you want to use the secure Web server the VeriSign certificate you ob tained to use with the previous configuration will not work with the new configuration You will need to obtain a new certificate If you have an existing key and certificate that you can use you will 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 19 9 If you are upgrading from th
93. your user account not as root You will see an introductory screen with key options including one recommended option the de fault similar to the following gpg GnuPG 1 0 7 Copyright C 2002 Free Software Foundation Inc This program comes with ABSOLUTELY NO WARRANTY This is free software and you are welcome to redistribute it under certain conditions See the file COPYING for details Please select what kind of key you want 1 DSA and ElGamal default 2 DSA sign only 4 ElGamal sign and encrypt 5 RSA sign only Your selection In fact most of the screens which require you to choose an option will list the default option within parentheses You can accept the default options by pressing Enter In the first screen you should accept the default option 1 DSA and ElGamal This option will allow you to create a digital signature and encrypt and decrypt with two types of technologies Type 1 and then press Enter Next choose the key size or how long the key should be Generally the longer the key the more resistant against attacks your messages will be The default size 1024 bits should be sufficiently strong for most users so press Enter Appendix B Getting Started with Gnu Privacy Guard 263 The next option asks you to specify how long you want your key to be valid Usually the default 0 key does not expire is fine If you do choose an expiration date remember that anyone with whom yo
94. 125 console making files accessible from 180 console access configuring 179 defining 180 disabling 180 disabling all 180 enabling 181 conventions document viii Cron 215 additional resources 220 configuration file 215 example crontabs 216 user defined tasks 216 crontab 215 CtrlAltDel shutdown disabling 179 270 D date configuration 183 dateconfig See Time and Date Properties Tool decryption with GnuPG 261 devel package 158 df 192 DHCP 135 additional resources 140 client configuration 140 command line options 139 connecting to 140 dhcpd conf 135 dhcpd leases 138 dhcrelay 139 global parameters 136 group 137 options 136 reasons for using 135 Relay Agent 139 server configuration 135 shared network 136 starting the server 138 stopping the server 138 subnet 136 dhcpd conf 135 dhcpd leases 138 dhcrelay 139 disk storage parted See parted diskcheck 193 documentation finding installed 243 DSA keys generating 122 DSOs loading 158 du 192 Dynamic Host Configuration Protocol See DHCP E e2fsck 16 e2label 32 encryption with GnuPG 261 Ethernet connection See network configuration exporting NFS file Systems 126 exports 128 ext2 reverting from ext3 16 ext3 converting from ext2 16 creating 16 features 15 F feedback xi file systems 192 ext2 See ext2 ext3 See ext3 LVM See LVM monitoring 193 NFS See NFS firewall configuration
95. AE magicdev A GNOME daemon for automatically mounting playing CDs v Package Information Full Name None Size None X dose Figure 32 2 Individual Package Selection After selecting package groups and individual packages to install click the Update button on the main window The application will then compute the amount of disk space required to install the packages as well as any package dependencies and display a summary window If there are package dependencies they will be automatically added to the list of packages to install Click the Show Details button to view the complete list of packages to be installed Completed System Preparation 1 packages are queued for installation P This will take 4 252 Kilobytes of diskspace Show Details X Cancel Continue Figure 32 3 Package Installation Summary Chapter 32 Package Management Tool 249 Click Continue to start the installation process When it is finished an Update Complete message will appear rip 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 32 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 be
96. Any URLs intended to connect to that virtual host must specify the port number in the URL The following URL example will attempt to connect to a non secure Web server listening on port 12331 Chapter 19 Apache HTTP Secure Server Configuration 167 http your_domain 12331 rote Some of the example URLs used in this manual may need to be changed depending upon whether you are accessing your secure Web server or your non secure Web server Please view all URLs in this manual as general examples and not as explicit instructions that will work under all circum stances 19 11 Additional Resources Refer to Section 18 7 for additional references about the Apache HTTP Server 19 11 1 Installed Documentation mod_ssl documentation Open a Web browser and go to the URL http localhost manual mod mod_ss on the server that is running the Apache HTTP Server 19 11 2 Useful Websites e Mailing list You can subscribe to the redhat secure server mailing list at http www redhat com mailing lists 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 line http www modssl org The mod_ssl 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 19 11 3 Related Books Apache The Definitive Gu
97. Apache HTTP Server daemon httpd running you can view the Apache HTTP Server documen tation Open a Web browser and go to the URL http localhost on the server that is running the Apache HTTP Server Then click the Documentation link usr share docs httpd lt version gt 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 18 7 2 Useful Websites http Awww apache org The Apache Software Foundation http httpd apache org docs 2 0 Apache HTTP Server Version 2 0 User s Guide http localhost manual index html After starting the Apache HTTP Server on your local system you can view the Apache HTTP Server Version 2 0 User s Guide using this URL http www redhat com support docs apache html Red Hat Support maintains a list of useful Apache HTTP Server links http www redhat com support docs faqs RH apache FAQ book1 html The Red Hat Linux Apache Centralized Knowledgebase compiled by Red Hat 18 7 3 Related Books Apache The Definitive Guide by Ben Laurie and Peter Laurie O Reilly amp Associates Inc 3 redhat Chapter 19 Apache HTTP Secure Server Configuration 19 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 co
98. Audio will not work without a proxy Low Security This option will not allow remote connections to the system including NFS connections and remote X Window System sessions Services that run below port 1023 will not accept connections including FTP SSH Telnet and HTTP Disable Firewall This option does not create any security rules It is recommended that this option only be chosen if the system is on a trusted network not on the Internet if the system is Chapter 12 Basic Firewall Configuration 109 behind a larger firewall or if you write your own custom firewall rules If you choose this option and click Next proceed to Section 12 3 The security of your system will not be changed 12 2 2 Local Hosts If there are Ethernet devices on the system the Local Hosts page allows you to configure whether the firewall rules apply to connection requests sent to each device If the device connects the system to a local area network behind a firewall and does not connect directly to the Internet select Yes If the Ethernet card connects the system to a cable or DSL modem it is recommended that you select No Local Hosts You seem to have an ethernet eth0 attached to your machine Shall trust the hosts that are connected via this card If this connection is your link to the internet eg cable madem you should say no Yes v lt Back X Cancel Figure 12 3 Local Hosts 12 2 3 DHCP If you are using
99. 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 backwards 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 autodetecting upgrade Upgrade the existing boot loader configuration preserving the old entries This option is only available for upgrades clearpart optional Removes partitions from the system prior to creation of new partitions By default no partitions are removed ote If the clearpart command is used then the onpart command cannot be used on a logical partition linux Erases all Linux partitions 42 Chapter 6 Kickstart Installations all Erases all partitions from the system drives Specifies which drives to clear partitions from initlabel Initializes the disk label to the default for your architecture 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 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 t
100. IRECT amp Cancel Back Figure 26 11 Adding a JetDirect Printer Text fields for the following options appear below the Queue Type menu as shown in Figure 26 12 Printer IP The hostname or IP address of the JetDirect printer Port The port on the JetDirect printer that is listening for print jobs The default port is 9100 206 Chapter 26 Printer Configuration Configure a Jetdirect Printer Enter the IP address of the JetDirect printer Use the default port of 9100 unless you know the printer is using a different port Printer IP printer example com Port 9100 Figure 26 12 Choosing a Print Server The next step is to select the type of printer that is connected to the JetDirect system Skip to Section 26 6 to continue 26 6 Selecting the Print Driver and Finishing After selecting the queue type of the printer the next step in adding a printer is to select the print driver You will see a window similar to Figure 26 13 If you are configuring a local printer and the model was autodetected the recommended driver is autoselected and marked with an asterisk If it was not autodetected select the driver from the list The printers are divided by manufacturers Click the arrow beside the manufacturer for your printer Find your printer from the expanded list and click the arrow beside the printer name A list of drivers for your printer will appear Select
101. 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 genericusb generic3usb geniusnm geniusnmps 2 geniusprops 2 geniusscrollps 2 geniusscrollps 2 thinking thinkingps 2 logitech logitechcc logibm logimman logimmanps 2 logimmant logimmantps 2 logimmusb microsoft msnew msintelli msintellips 2 msintelliusb msbm mousesystems mmseries mmhittab sun none If the mouse command is given without any arguments or it is omitted the installation program will attempt to autodetect the mouse This procedure works for most modern mice network optional 1 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 con figured for the system If the installation does require networking and network information is not provided in the kickstart file the Red Hat Linux installation program assumes that the in stallation should be done over ethO via a dynamic IP address BOOTP DHCP and configures the final installed system to determine its IP address dynamically The network option config ures networking information
102. In these situations you may be unable to boot Red Hat Linux If you can get into rescue mode you might be able to resolve the problem or at least get copies of your most important files 76 Chapter 8 Rescue Mode 8 2 Booting Rescue Mode To boot your system in rescue mode boot from a Red Hat Linux boot disk or the Red Hat Linux CD ROM 1 and enter the following command at the installation boot prompt boot linux rescue You can get to the installation boot prompt in one of these ways By booting your system from an installation boot diskette made from the boot img image This method requires that the Red Hat Linux CD ROM 1 be inserted as the rescue image or that the rescue image be on the hard drive as an ISO image By booting your system from the Red Hat Linux CD ROM 1 By booting from a network disk made from the bootnet img or PCMCIA boot disk made from pcmcia img You can only do this if your network connection is working You will need to identify the network host and transfer type For an explanation of how to specify this information refer to the Official Red Hat Linux Installation Guide After booting off a boot disk or Red Hat Linux CD ROM 1 and providing a valid rescue image you will 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 t
103. OR is the minor number of the parti tion you want to remove Wee 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 swap space 22 Chapter 2 Swap Space 3 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 will appear 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 manne
104. P Server Configuration 18 1 Basic Settings 19 2 Default Seting Siss is sesistessssreusecscetessuscsguastutescsovuupdatateusasuaipaiauctanes AEA 145 18 3 Virtual Hosts Settings wise tai e clk ahead radians EAER 150 19 4 Serv r Seting Saentos taR EREE E RE ET 153 18 5 Performance Tuning 18 6 Saving Your Settings 18 7 Additional Resources 19 Apache HTTP Secure Server Configuration p157 19 1 Introductio jesienna ienie 157 19 2 An Overview of Security Related Packages 00 0 0 ccc cessseseeseeeseeeees 157 19 3 An Overview of Certificates and Security 19 4 Using Pre Existing Keys and Certificates 19 5 Types of Certificates s oon noy NADERI ESE E P EEIT E EAST 160 19 6 Generating a Key ieatsssnbcess Sea ccsssTaosiadossssssds ak beosdaasessheatsasesssssdazeobdstarguavssevseisbeueds 161 19 7 Generating a Certificate Request to Send to a CA 163 19 8 Creating a Self Signed Certificate 164 19 9 Testing Your Certificate 19 10 Accessing Your Secure Server 166 19 11 Additional Resources 167 20 BIND Configuratio Mea aae E Er ET A Er E 169 20 1 Adding a Forward Master Zone ss ssssseissesrsseetesrsrisessrsresesstsrsntsrssrsensrsreres 169 20 2 Adding a Reverse Master Zone 20 3 Adding a Slave Zone 21 Mail Transport Agent MTA Configuration s sesssssesssssesstsresessssrtrtsrssrertsrssisrrrrnrresn 175 TV System Configuration cc
105. Red Hat Linux 8 0 The Official Red Hat Linux Customization Guide 3 redhat Red Hat Linux 8 0 The Official Red Hat Linux Customization Guide Copyright 2002 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 rhl cg EN 8 0 Print RHI 2002 08 14T17 28 0400 Copyright 2002 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 o
106. Removing Swap Space 2 4 Moving Swap Space 3 Redundant amey of Independent Disks RAID airdri eea e 23 3 4 RAID Levels and Linear Support 24 4 Logical Volume Manager LVM 227 5 Managing Disk Storage w29 5 1 Viewing the Partition Tab e 30 5 2 Creating a Partition 30 5 3 REMOVING A PAartitlON s sssini ieis ranio a AEE E aE aa Eiei a 32 5 4 Resizing a Partitone nr EAEE wi A S 33 IL Installation Related Information seeseseesesroressesroroseosesresesoreseoseseoreseoseorosesrceronesroseeeesesroseseosess 35 6 Kickstart Installations 252ss22sch cisdessesescaiecsastectsdacteiasoadedaasuanszssvaiacsecsaccasteaessazautevcaseabansscates 37 6 1 What are Kickstart Installations sesseeeeseeeeseeeeseestsrsssresrsrsresesrsrsesrsesrersesrneee 37 6 2 How Do You Perform a Kickstart Installation 00 0 cceeeseeeseeeeteeceeeeeeeeeeeeeeaeeee 37 6 3 Creating the Kickstart File ves 6 4 Kickstart O pti ons eena nnna a a a 63 Package Selection sirien iiser see iri n ESAE E DASE KE An EIEEE suvengesapeseesty 6 6 Pre installation Script 6 7 Post installation Script 6 8 Making the Kickstart File Available 6 9 Making the Installation Tree Available 6 10 Starting a Kickstart Installation sh 7a Kickstart Configurator ici los ar yE SEE SEEE E NEVAS Sei Tale Basi Configuration arii ese pareret ai ANNEES NEE on ASAA VANESSA SEE soveuesbacec
107. 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 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 40 Chapter 6 Kickstart Installations enablehesiod Enable Hesiod support for looking up user home directories UIDs and shells More infor mation on setting up and using Hesiod on your network is in 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 he
108. Tool 32 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 32 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 extra 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 gt Standard Packages V Extra Packages v eog Eye of GNOME image viewer gftp A multithreaded FTP client for the X Window System gimp print utils Epson inkjet printing utility programs from gimp print gnome media GNOME media programs gnome vfs extras The GNOME virtual file system extra modules gnome vfs2 extras Extra modules for version 2 of the GNOME virtual file system gqview An image viewer gtk engines Theme engines for GTK gtk2 engines Theme engines for GTK 2 0 EEX AR AR
109. 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 your_domain com when your server s real DNS name is actually foo your_domain 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 18 2 will appear Either choose the Listen to all addresses option to listen to all IP addresses on the defined port or specify a particular IP address over which the server will accept connections in the Address field Only specify one IP address per port number If you want to specify
110. YWxsQHJ12ZGhhdC5 jb20 i FYEEXECABYFA jkHP 3UECWOEAWMV AwIDFgIBAheAAAOJEJECmvGCP SWpM jQAONF 2zvRgdR 80r9pBhu95zeSnkb7AKCm aXVS0a5KON7J61 1VEwx1 1poLkBDQQ5Bz MEAQA8 zt CWRU jW8cHCgLaE402 jyqQ 37gDT n4VS66nU YIt zDFScVmgMuFRzhibLb1 09TpZzxEbSF 3T 6p 9HLLNHCOQ1bD HRsKf h0eJYMMqB3 HyUpNeqCMEEd9AnWD 9P 4rQtO7Pes38sV01X00SvsTyMG9IWEB vSNZk R1 phA55r1s8cAAWUEAJ jqazvk0bgFrwlOPG9m7 fEeD1VPSV6HSA0 fvz4w c7ckfpuxg URON 3TJA00Acprk8Gg8J2CtebAyR sP5IsrK5111luGdk 10M85FpT cen20dJt ToAF 6fGnIkeCeP105aWTbDgdAUHBRykpdWU3GJ7NS 6923 f Vg5khOWg uwrAiEYEGBECAAYFAjkHP4wACgkOkOKa8YI 9JamliwCfXox HjlorMKnQRJkeBcZ iLyPH1QA0I33Ft O0HBqLt qdtP4vWYORbibjW BMEc B 5 1 Exporting to a Keyserver If you are only writing to a few correspondents you can export your public key and send it to them personally If you correspond with many people however distribution of your key can be time con suming Instead you can use a keyserver A keyserver is a repository on the Internet which can store and distribute your public key to anyone who requests it Many keyservers are available and most try to remain synchronized with each other sending your key to one keyserver is like distributing it to them all A correspondent can request your public key from a from a keyserver import that key to their keyring and they are ready for secure correspondence with you rip Because most keyservers are synchronized sending your public key to one keyserver is usually as good as se
111. ablenis 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 Chapter 6 Kickstart Installations 39 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 the name of the LDAP server to use This option is set in the etc ldap conf file ldapbasedn If you specified either enableldap or enableldapauth the DN distinguished name in your LDAP directory tree under which user information is stored This option is set in the etc ldap conf file enableldaptls Use TLS Transport Layer
112. ach print request such as the status of 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 To view the list of print jobs in the print spool open a shell prompt and 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 26 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 lprm 902 would cancel the print job in Example 26 1 You must have proper permissions to cancel 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 a format the printer can understand 26 12 Configuring the CUPS Printing System CUPS Common UNIX Printing System can be used instead of the default LPRng printing system Some of the advantages of CUPS include Support for IPP next generation network printing protocol Autodetection of network printers Web interface configuration tool Support for PPD printer description files Su
113. address or hostnames or on a pattern of clients See the Official Red Hat Linux Reference Guide and the host s_access man page for details 13 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 etc xinetd runs constantly and listens on all of the 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 you will notice upon inspection of the file that it only contains a few defaults and an instruction to include the etc xinetd d directory To enable or disable a 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 Services Configuration Tool ntsysv or chkconfig For a list of network services controlled by xinetd list of the contents of the etc x
114. an 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 Linux If you need 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 typing hdd ide scsi as a kernel parameter where hdd is the CD ROM device 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 you choose GRUB as the boot loader you can password protect it by configuring a GRUB password Enter a password in the Use GRUB password text entry area If you want to save the password as an encrypted password in the file select Encrypt GRUB password When the file is saved the plaintext 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 If you selected to Upgrade an existing installation on the Installation Method page you can select Upgrade existing boot loader to upgrade the existing boot loader configuration while preserving the old entries Chapter 7 Kickstart Configurator 63 7 4 Partition Information File Help Basic Configuration Partition Infor
115. an view them with any text editor such as Vi or Emacs Some log files are readable by all users on the system however you must be logged in as root 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 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 your list might differ from the one shown in Figure 28 1 To view the complete list of log files that it can view refer to the configuration file etc sysconfig redhat logviewer 222 Eile Edit Help Boot Log Cron Log Kernel Startup Log FTP Log Apache Access Log Apache Error Log Mail Log MySQL Server Log News Log RPM Packages Security Log Update Agent Log XFree86 Log System Log S This is the system log file Aug 16 15 12 19 falcon automount 746 attempting to mount entry mnt redhat iB Aug 16 15 12 20 falcon automount 706 attempting to mount entry home cpruitt Aug 16 15 13 31 falcon automount 3321 expired home cpruitt Aug 16 15 18 41 falcon automount 3375 expired mntjredhat Aug 16 15 35 47 falcon automount 746 attempting to mount entry mnt redhat Aug 16 15 41 12 falcon automount 3500 expired mnt redhat Aug 16 15 51 07 falcon automount 746 attempting to mount entry mnt redhat Aug 16 15 52 50 falc
116. ard 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 Add button 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 92 Chapter 11 Network Configuration Select ISDN Adapter F ISDN Adapters ACER P10 El Resource D Channel Protocol IRQ 5 2 Euro ISDN EDSS1 MEM O 1TR6 10o 0x300 lon 102 X Cancel pack gt Forward Figure 11 3 ISDN Settings 5 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 the values contact your ISP Click Forward 6 On the Create Dialup Connection page click Apply After configuring the ISDN device it appears in the device list as an ippp device as shown in Figure 11 4 Active Profile Common z New Devices Hardware Hosts DNS physical hardware here Multiple logical devices can be a2 You may configure network devices associated with a i associated with a single piece of hardware Profile Status Device Nickname T
117. at are optimized for different x86 versions The options are athlon for AMD Athlon and AMD Duron systems i686 for Intel Pentium II Intel Pentium III and Intel Pentium 4 systems and i586 for Intel Pentium and AMD K6 systems If you do not know the version of your x86 system use the kernel built for the i386 version it is built for all x86 based systems The x86 version of the RPM package is included in the file name For example kerne1 2 4 18 7 95 athlon rpm is optimized for AMD Athlon and AMD Duron systems and kernel 2 4 18 7 95 1686 rpm is optimized for Intel Pentium II Intel Pentium III and Intel Pentium 4 systems When you have determined which packages you need to upgrade your kernel select the proper architecture for the kernel kernel smp and kerne1 bigmem packages Use the i386 versions of the other packages 29 3 Downloading the Upgraded Kernel There are several ways to determine if there is an updated kernel available for your system Chapter 29 Upgrading the Kernel 227 Go to http www redhat com apps support errata choose the version of Red Hat Linux you are using and view the errata for it Kernel errata are usually under the Security Advisories section From the list of errata click the kernel errata to view the detailed errata report for it In the errata report there is a list of required RPM packages and a link to download them from the Red Hat FTP site You can also dow
118. at connected to it 18 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 156 Chapter 18 Apache HTTP Server Configuration 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 conf httpd conf bak Oi 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 18 7 Additional Resources To learn more about the Apache HTTP Server refer to the following resources 18 7 1 Installed Documentation Apache HTTP Server documentation If you have the htt pd manual package installed and the
119. ation 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 Linux system with an Internet connection 12 1 Security Level Configuration Tool During the Firewall Configuration screen of the Red Hat Linux installation you were given the option to choose a high medium or no security level as well as allow specific devices incoming services and ports After installation you can change the security level of your system by using Security Level Config uration Tool If you prefer a wizard based application refer to Section 12 2 To start 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 ig E Please choose the security level for the system Security Level High v Use default firewall rules Customize Figure 12 1 Security Level Configuration Tool Select the desired security level from pulldown menu High
120. before rebooting root pw required Sets the system s root password to the lt password gt argument rootpw iscrypted lt password gt 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 Chapter 6 Kickstart Installations 51 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 sube If present the system assumes the hardware clock is set to UTC Greenwich Mean time upgrade optional 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 If this argument is not provided the installat
121. begin with letters Queue Name test Queue Type Local Printer LOCAL Unix Printer LPD Windows Printer SMB Novell Printer NCP JetDirect Printer JETDIRECT amp Cancel Back Figure 26 3 Adding a Local Printer Printer Configuration Tool attempts to detect your printer device and model as shown in Figure 26 4 If your printer device is not shown click Custom Device Type the name of your printer device and click OK to add it to the printer device list A printer device attached to the parallel port is usually referred to as dev 1p0 A printer device attached to the USB port is usually referred to as dev usb1p0 If your printer model does not appear you will be given the opportunity to select it in the next step Click Next to continue 200 Chapter 26 Printer Configuration Configure a Local Printer Select the printer device to use or use the custom option if it is not listed Device Model dev p0 HP LaserJet 2100 Rescan Devices l Custom Device X amp Cancel Back Figure 26 4 Local Printer Device If Printer Configuration Tool detected your printer model it will display the recommended print driver Skip to Section 26 6 to continue 26 2 Adding a Remote UNIX Printer To add a remote UNIX printer such as one attached to a different Linux system on the same network click the New button
122. board U S English Partition Information Network Configuration Mouse Generic Mouse PS 2 v Authentication Emulate 3 Buttons Firewall Configuration J Time Zone America New_York v X Configuration i Package Selection Root Password Pre Installation Script Z Encrypt root password Post installation Script Language Support 7 Chinese Mainland Chinese Taiwan Czech LI Danish English French C German C Icelandic gt Italian L Japanese D Reboot system after installation Perform installation in text mode graphical is default Oo Lo Perform installation in interactive mode Figure 7 1 Basic Configuration Choose the language to use during the installation and as the default language after installation from the Language menu Select the system keyboard type from the Keyboard menu Choose the mouse for the system from the Mouse menu If you choose No Mouse no mouse will be configured If you choose Probe for Mouse the installation program will try to autodetect the mouse Probing works for most modern mice If you have a two button button mouse you can emulate a three button mouse 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 60 Chapter 7 Kickstart Configurator From the Time Zone menu
123. boot diskette insert a blank floppy disk and use the images boot img file on the Red Hat Linux CD ROM 1 with the command dd if boot img of dev fdo Chapter 8 Rescue Mode 77 If your filesystem is mounted and you want to make your system the root partition use the 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 From the bash prompt you can run many useful commands including anaconda gzip mkfs ext2 probe badblocks head mknod ps bash hwclock mkraid python2 2 cat ifconfig mkswap raidstart chattr init mlabel raidstop chmod insmod mmd rep chroot less mmount rlogin clock in mmove rm collage loader modprobe rmmod cp ls mount route cpio lsattr mpartition rpm dd lsmod mrd rsh ddcprobe mattrib mread sed depmode mbadblocks mren sh df mcd mshowfat sync e2fsck mcopy mt tac fdisk mdel mtools tail fsck mdeltree mtype tar fsck ext2 mdir mv touch fsck ext3 mdu mzip traceroute ftp mformat open umount gnome pty helper minfo parted uncpio grep mkdir pico uniq gunzip mke2fs ping zcat 8 3 Booting Single User Mode You may be able to boot single user mode directly If your system boots but does not allow you to log in when it has completed booting try single user mode If you are using GRUB use the following steps to boot into single user mode 1 If you have a GRUB
124. by unselecting Create home directory Red Hat 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 simply 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 will be assigned to the new user Red Hat Linux reserves user IDs above 500 for system users Click OK to create the user User Name tfox Full Name Tammy Fox Password aterm tona Confirm Password tree Login Shell binfbash v Create home directory Home Directory home tfox Create a private group for the user Specify user ID manually X Cancel Box Figure 24 2 New User To configure more advanced user properties such as password expiration modify the user s properties after adding the user Refer to Section 24 2 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 24 2 Mo
125. can make a RAID device Make RAID Device Mount Point home File System Type ext3 b RAID Device mdo t RAID Level RAIDO t 4 hda2 2996 MB 4 hda3 2996 MB RAID Members Number of spares 0 X Cancel Pox Figure 9 2 Making a RAID Device 3 Enter a mount point 4 Choose the filesystem type for the partition 5 Choose your RAID level You can choose from RAID 0 RAID 1 and RAID 5 rote 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 boot 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 6 Select which partitions will go into this RAID array and click OK 7 A spare partition can be specified for RAID 1 and RAID 5 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 Select the number of spares o0 Select whether you want the partition formatted Chapter 9 Software RAID Configuration 81 9 The RAID device will appear in the Drive Summary list as
126. cause the boot loader can not read it If you want to have your root partition on a logical volume you will need to create 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 rote 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 Edit LVM Device Volume Group Name Volumeod Physical Extent 4MB ae ir hda2 19384 00 MB Ms 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 Jox Figure 10 2 Creating an LVM Device 2 Change the Volume Group Name if desired Chapter 10 LVM Configuration 85 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 instal
127. 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 will 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 will 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 Chapter 19 Apache HTTP Secure Server Configuration 165 19 8 Creating a Self Signed Certificate You can create your own self signed certificate Please note that a self signed certificate will not provide the security guarantees provided by a CA signed certificate See Section 19 5 for more details about certificates If you would like to make your own self signed certificate you will first need to create a random key using the instructions provided in Section 19 6 Once you have a key make sure you are in the usr share ssl certs directory and type the following command make testcert You will see the following output and you will be prompted for your password unless you generated a key without a password 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 PEM pass phrase After you enter your password or withou
128. cess 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 is ignored If at allow does not exist all users listed in at deny are not allowed to use at or batch 27 3 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 Refer to Chapter 13 for details on starting the cron service automatically at boot time 27 4 Additional Resources To learn more about configuring automated tasks refer to the following resources 27 4 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 usr share doc at lt version gt timespec contains more detailed information about the times that can be specified for cron jobs anacron man page description of anacron and its command line options anacrontab man page brief overview of the anacron configuration file usr share doc anacron lt version gt README describes Anacron and why it is useful at man page description of at and batch and their command line options 3 redhat Chapter 28 Log Files Log files are files that contain mes
129. ch 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 warning Changes take place immediately be careful when you type e Exit parted by typing quit 20 Chapter 2 Swap Space 3 Now that you have the swap partition use the command mkswap to setup the swap partition At a shell prompt as root type the following mkswap 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 00 The next time the system boots it will enable the new swap partition 6 After adding the new swap partition and enabling it make sure it is enabled by viewing the output of the command cat proc swaps or free To add a swap file pi Determine the size of the new swap file 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
130. cognizes 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 you install a card after installation Kudzu should recognize it and prompt you to configure the corresponding kernel module for it Be sure to check the Red Hat Linux 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 30 for details on loading kernel modules To configure a DHCP client manually you need to modify the etc sysconfig network file 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 eth0 is the network device name The etc sysconfig network file should contain the following line NETWORKING yes You might have more information in this file but 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 You need a configuration file for each device that you want to configure to use DHCP If you prefer a graphical interface for configuring a DHCP client refer to Chapter 11 for details on u
131. 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 will be 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 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 132 Chapter 16 Samba 16 2 1 Samba Passwords In Red Hat Linux 8 0 encrypted passwords are enabled by default because it is more secure If en crypted 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 2000 and Win dows NT 4 0 with Service Pack 3 or higher require encrypted Samba passwords To use Samba be tween a Red Hat Linux system and a system with Windows 2000 or Windows NT 4 0 Service Pack 3 or higher you can either edit your Windows registry to use plaintext passwords or configure Samba on your
132. connection Your browser will 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 You can just accept the defaults by clicking Next until the dialogs are finished Once your browser accepts the certificate your secure Web server will show you a default home page 19 10 Accessing Your Secure Server To access your secure server use a URL like this https your_domain Note that URLs which are intended to connect to your secure Web server should begin with the https protocol designator instead of the more common http protocol designator Your non secure server can be accessed using an URL like this http your_domain The standard port for secure Web communications is port 443 The standard port for non secure Web communications is port 80 The secure Web server default configuration listens on both of the two standard ports Therefore you will 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 i e anything besides 80 or 443 you will need to 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
133. 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 22 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 lt sound gt dev dsp dev audio dev midi dev mixer dev sequencer Chapter 22 Console Access 181 dev sound lt cdrom gt dev cdrom dev cdwriter You can add your own lines to this section if necessary Make sure that any lines you add refer to the appropriate device For example you could add the following line lt scanner gt dev scanner Of course make sure that dev scanner is really your scanner and not say your hard drive That s 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
134. ctory 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 27 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 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 user names listed in the access control files Chapter 27 Automated Tasks 217 Tf 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 all users listed in cron deny are not allowed to use cron 27 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 13 for details on starting the cron service automatically at boot time 27 2 Anacron Anacron is a task scheduler similar to cron except that it does not require the system to run continu ously It can be used to run the daily weekly and monthly jobs
135. ctory 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 project52 on the remote machine penguin host 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 host net project52 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 ote 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
136. d Hat Linux manuals are available on the Documentation CD and online at http www redhat com docs rote Although this manual reflects the most current information possible you should read the Red Hat Linux Release Notes for information that may not have been available prior to our documentation being finalized They can be found on the Red Hat Linux CD 1 and online at http www redhat com docs manuals linux 1 Changes to This Manual This manual has been expanded to include new features in Red Hat Linux 8 0 as well as topics re quested by our readers Significant changes to this manual include File Systems New to this version is a file systems part It discusses ext3 swap space RAID LVM and man aging disk storage with parted viii Introduction Kickstart The kickstart options have been updated to include the new options in Red Hat Linux 8 0 and the Kickstart Configurator chapter has been updated to include many new features LVM Configuration This new chapter discusses how to configure LVM during installation Network Configuration The network configuration chapter now includes information on network profiles and network aliases Basic Firewall Configuration This chapter includes the new Security Level Configuration Tool Network File System NFS This chapter now includes how to export directories using the NFS Server Configuration Tool Apache HTTP Server Both Apache HTTP Server chapters have been upda
137. 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 15 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 130 Chapter 15 Network File System NFS Stop the NFS daemon with the following command sbin service nfs stop To start the nfs service at boot time use the command 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 13 for details 15 4 Additional Resources This chapter discusses the basics of using NFS For more detailed information refer to the following resources 15 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 15 4 2 Useful Websites http www tldp org HOWTO NFS HOWTO index html The Linux NFS HOWTO from the Linux Documentation
138. definable e 5 Full multi user mode with an X based login screen e 6 Reboot If you configured the X Window System during the Red Hat Linux installation program you had the option of choosing a graphical or text login screen If you chose a text login screen you are operating in runlevel 3 If you chose 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 3 initdefault Change the number in this line to the desired runlevel The change will 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 13 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
139. demonstrated in Example 17 3 the group declaration can be used to apply global parameters to a group of declarations You can group shared networks subnets hosts or other groups group option routers 192 1 68 1 25 43 option subnet mask 255 255 255 0 7 option domain name example com option domain name servers L922 V6 Bs O 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 17 3 Group Declaration To configure a DHCP server that leases a dynamic IP address to a system within a subnet modify Example 17 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 17 4 Range Parameter To assign an IP address to a client based on the MAC address of the network interface card use the hardware et
140. der the new kernel pkg script should have modified boot 1lilo conf to include a section for the new kernel and run sbin lilo The default LILO configuration file looks similar to the following prompt timeout 50 default linux boot dev hda map boot map install boot boot b message boot message lba32 image boot vmlinuz 2 4 18 7 95 label linux initrd initrd 2 4 18 7 95 img read only append root LABEL The modified etc lilo conf should look similar to the following Appendix A Building a Custom Kernel 259 prompt timeout 50 default linux boot dev hda map boot map install boot boot b message boot message lba32 image boot vmlinuz 2 4 18 7 95custom label 2 4 18 7 95custom initrd initrd 2 4 18 7 95custom img read only append root LABEL image boot vmlinuz 2 4 18 7 95 label linux initrd initrd 2 4 18 7 95 img read only append root LABEL If the file is not modified correctly and you did not receive any error messages from make install add the new section manually To activate the changes run the command sbin lilo v If all goes well you will see output similar to the following LILO version 21 4 4 Copyright C 1992 1998 Werner Almesberger 1lba32 extensions Copyright C 1999 2000 John Coffman Reading boot sector from dev hda Merging with boot boot b Mapping message file boot message Boot image boot vmlinuz 2 4 18 7 95custom Added 2 4 18 7 95custom Boot image boot
141. difying 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 pull down menu A window similar to Figure 24 3 will appear Chapter 24 User and Group Configuration 187 User Data Account Info Password Info Groups User Name tfox Full Name Tammy Fox Password Confirm Password Home Directory homeytfox Login Shell bin bash m X Cancel Pox Figure 24 3 User Properties The User Properties window is divided into tabbed pages User Data 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 can not log in to the system Password Info This tab shows the date that the user last changed his password To force the user to change his password after a certain number of days select Enable password expiration You can also set the number of days before the user is allowed to change his password the number of days before the user is warned to change his password and days before the account become inactive Groups
142. displayed You will be prompted to enter the number rip 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 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 prefer
143. does not support the fonts you are trying to print try selecting this option For example you should select this option if you are printing Japanese fonts to a non Japanese printer Extra time is required to perform this action Do not choose it unless you are having problems printing the correct fonts You should also select this option if your printer can not handle PostScript level 3 This option converts it to PostScript level 1 Convert Text to Postscript is selected by default If your printer can print plain text try unselecting this when printing plain text documents to decrease the time it takes to print Page Size allows you to select the paper size for your printer such as US Letter US Legal A3 and A4 Effective Filter Locale defaults to C If you are printing Japanese characters select ja_JP Other wise accept the default of C Media Source defaults to Printer default Change this option to use paper from a different tray If you modify the driver options click OK to return to the main window Click Apply to save the change and restart the printer daemon 210 Chapter 26 Printer Configuration 26 9 Saving the Configuration File When you save your printer configuration using Printer Configuration Tool it creates its own con figuration file that is used to create the etc printcap file that the printer daemon 1pd reads You can use the command line options to save or restore this file If you save your etc
144. dule you need to set up the dynamic loading mechanism Kudzu runs when the system boots and usually detects new hard ware You can also add the new driver by editing the module configuration file etc modules conf For example if your system included a model SMC EtherPower 10 PCI network adapter at the time of installation the module configuration file will contain the following line alias eth0 tulip After installation if you install a second identical network adapter to your system add the following line to etc modules conf alias ethl tulip See the Official Red Hat Linux Reference Guide for an alphabetical list of kernel modules and the hardware supported by the modules 30 1 Kernel Module Utilities You can also use a group of commands to list load or unload kernel modules These commands are useful if you want to try different modules or see if a module has been loaded successfully The command sbin 1smod displays a list of currently loaded modules Module Size Used by sr_mod 15264 0 autoclean mga 95984 ak agpgart 23392 3 nfs 79008 1 autoclean lockd 52464 1 autoclean nfs sunrpc 61328 1 autoclean nfs lockd autofs 11264 4 autoclean 3c59x 25344 1 autoclean ipchains 38976 0 unused ide scsi 8352 0 scsi_mod 95104 2 sr_mod ide scsi ide cd 26848 0 cdrom 27232 0 sr_mod ide cd usb uhci 20720 0 unused usbcore 49664 1 usb uhci Example 30 1 Example 1smod output 232 Chapter 30 Kern
145. dy installed If you want 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 31 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 you will see Preparing AEAEE EAE AE EARTH AE AE AE AE AE E AE AE AE AE AE AE RA AEE 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 31 2 2 3 Unresolved Dependency RPM packages can depend on other packages which means that they require other packages to be installed in order to run properly If you try to install a package which has an unresolved dependency you will see Preparing AEAEE E AEAEE AE AE AE AE AE AE AE E AE AE AE AE AE AE AE EAE AE RAH E E 1005 error Failed dependencies bar so 2 is needed by foo 1 0 1 Suggested resolutions bar 2 0 20 3 1386 rpm 238 Chapter 31 Package Management with RPM If you are installing an official Red Hat it will usually suggest the package s need to resolve the
146. e If you use the Add button a network alias will be created which is not correct The device name should not end with a colon followed by a number 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 Figure 11 17 shows a profile called Office with the logical device eth0_office It is configured to activate the first Ethernet card using DHCP Active Profile X Office New Rename Remove Devices Hardware Hosts DNS FT E You may configure network devices associated with o physical hardware here Multiple logical devices can be Profile Status Device Nickname associated with a single piece of hardware Type Add v amp Active amp Active etho eth0_office Ethernet Ethernet etho etho_home Edit Copy Delete Activate Deactivate B Hep Y Apply X Close Figure 11 17 Office Profile Notice that the Home profile as shown in Figure 11 18 activates the eth0_home logical device which is associated with ethO and is configured to use a static IP address
147. e 7 17 Preview To save the kickstart file select File gt Save File or press Ctrl S A file dialog box will appear to allow you to select where to save the file After saving the file refer to Section 6 10 for information on how to start the kickstart installation 3 redhat Chapter 8 Rescue Mode 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 and single user mode where you can use your own knowledge to repair the system 8 1 What is Rescue Mode Rescue mode provides the ability to boot a small Linux environment entirely from a diskette CD ROM or using some other method As the name implies rescue mode is provided to rescue you from something During normal opera tion your Red Hat 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 Linux running completely enough to access its 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 Linux from that hard drive Normally you will need to get into rescue mode for one of two reasons You are unable to boot Linux You are having hardware or software problems and you want to get a few important files off your system s
148. e Queue Type menu and click Next If the printer is attached to a Microsoft Windows system choose this queue type Set the Print Queue Name and Type Enter the Queue s name and select the Queue s Type Valid names can contain the characters a z A Z 0 9 and _ They must begin with letters Queue Name test3 Queue Type Local Printer LOCAL ix Pri LPD i SMB 5 Novell Printer NCP JetDirect Printer JETDIRECT 3X Cancel Back Forward Figure 26 7 Adding a SMB Printer Text fields for the following options appear as shown in Figure 26 8 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 Notice the syntax of machinename sharename User 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 Host IP The hostname or IP address of the remote system that is sharing the SMB printer Password The password if required for the user specified in the User field Chapter 26 Printer Configuration 203 Workgroup The name of the workgroup on the machine running Samba Click the Translate n gt r n button to translate the end of line characters to a form
149. e Red Hat Secure Web Server versions 1 0 and 2 0 your old key httpsd key and certificate httpsd crt will be located in etc httpd conf You will need to move and rename your key and certificate so that the secure Web 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 Web server with the command sbin service httpd start For a secure server you will be prompted to enter your password After you type it in and press Enter the server will start You should not need to get a new certificate if you are upgrading from a previous version of the secure Web server Chapter 19 Apache HTTP Secure Server Configuration 161 19 5 Types of Certificates If you installed your secure Web server using the Red Hat Linux installation program a random key and a test certificate are generated and put into the appropriate directories Before you begin using your secure server however you will need to generate your own key and obtain a certificate which correctly identifies your server You need a key and a certificate to operate your secure Web server which means that you can either generate 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
150. e essentially the same That is all you need to do Regardless of whether you use the shell prompt or the Web you will see a message that your key was successfully submitted either at the shell prompt or at the keyserver s website From now on users who want to communicate securely with you can import your public key and add it to their keyring B 6 Importing a Public Key The other end of key exchange is importing other people s public keys to your keyring is just as simple as exporting keys When you import someone s public key you can decrypt their email and check their digital signature against their public key on your keyring One of the easiest ways to import a key is to download the key or save it from a website After downloading a key and saving it to the file key asc use the following command to add it to your keyring gpg import key asc Another way to save a key is to use a browser s Save As feature If you are using a browser such as Mozilla and you locate a key at a keyserver you can save the page as a text file go to File gt Save Page As In the drop down box next to Files of Type choose Text Files txt Then you can import the key but remember the name of the file you saved For example if you saved a key as a text file called newkey txt to import the file at a shell prompt type the following command gpg import newkey txt Appendix B Getting Started with Gnu Privacy Guard 267 T
151. e key is written to ssh id_dsa It is important never to give anyone the private key 2 Change the permissions of your ssh directory using the command chmod 755 ssh 3 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 does not exist you can copy the file ssh id_dsa pub to the file ssh authorized_keys on the other machine 4 If you are running GNOME skip to Section 14 3 4 4 If you are not running the X Window System skip to Section 14 3 4 5 14 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 Red Hat Linux 8 0 systems 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 Chapter 14 OpenSSH 123 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
152. e latest data The Bind Configuration Tool increments this number each time the configura tion 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 Nameservers Add edit and delete name servers for the reverse master zone At least one nameserver is required 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 you can add 192 168 10 1 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 172 Chapter 20 BIND Configuration Reverse Master Zone IP Address 192 168 10 Reverse IP Address 10 168 192 in addr arpa Contact root localhost File Name 10 168 192 in addr arpa zone Primary Nameserver SOA Serial Number 1 Set Time Settings Nameservers Add Edit Reverse Address Table Delete Address Host or Domain Add Edit Delete X Cancel oK Figure 20 3 Adding a Reverse Master Zone The configuration shown in Figure 20 3 creates the following entry in etc named conf zone 10 168 192 in addr arpa type master file 10 168 192 in addr arpa zo
153. e of printer that is connected to the remote NCP system Skip to Section 26 6 to continue Chapter 26 Printer Configuration 205 rote If you require a username and password for a NCP NetWare print queue they are stored Thus it is possible for another person to learn the username and password To avoid this the username and password to use the printer should be different from the username and password used for the user s account on the local Red Hat Linux system If they are different then the only possible security compromise would be unauthorized use of the printer 26 5 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 26 1 will appear Click Next to proceed You will see the screen shown in Figure 26 11 Enter a unique name for the printer in the Queue Name text field The printer name cannot contain spaces and must begin with a letter a through z or A through Z The valid characters are a through z A through Z O through 9 and _ Select JetDirect Printer from the Queue Type menu and click Next Set the Print Queue Name and Type Enter the Queue s name and select the Queue s Type Valid names can contain the characters a z A Z 0 9 and __ They must begin with letters Queue Name test5 Queue Type Local Printer LOCAL Unix Printer LPD D Windows Printer SMB Novell Printer NCP s JETD
154. e of the predefined servers or type a server name in the pulldown menu Your system will not start synchronizing with the NTP server until you click OK After you click OK the configuration will be saved and the NTP daemon will be started or restarted if it is already running If you want this daemon to start automat ically at boot time you need to execute the command sbin chkconfig level 345 ntpd on to enable nt pd for runlevels 3 4 and 5 For more information on NTP read the NTP documentation available in the usr share doc ntp lt version gt directory The NTP server is written to the etc ntp conf and etc ntp step tickers files Clicking the OK button will apply any changes that you have made to the date and time the NTP daemon settings and the time zone settings and then exit the program warning If you configured a medium or high security level during installation or with Security Level Config uration Tool the firewall rules will block the connection to the NTP port To allow NTP to work run the Security Level Configuration Tool select Customize and add udp ntp to the other ports 23 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 will appear and the time zone select
155. e 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 partition Mount Point home v File System Type ext3 z RAID Device mdo z RAID Level 0 Z raid o1 Raid Members Number of spares 1 7 Format RAID device X Cancel Pox Figure 7 7 Creating a Software RAID Device 4 Click OK to add the device to the list 66 Chapter 7 Kickstart Configurator 7 5 Network Configuration File Help Basic Configuration Network Configuration Installation Method Network Type DHCP Static IP None Boot Loader Options Partition Information IP Address Authentication Netmask Firewall Configuration Gateway I X Configuration Package Selection Name Server H Pre Installation Script Post installation Script Figure 7 8 Network Configuration There are three network configuration options DHCP Static IP and None If there is not an Ethernet card in the system choose None Networking is only required if you choose a networking type installation method NFS FTP or HTTP If you are unsure which to choose choose None Networking can always be configured after installation with the Network Administration To
156. e 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 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 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 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 Chapter 6 Kickstart Installations 49 onpart or usepart Put the partition on the already existing device For example partition home onpart hdal 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 bytes
157. ed the changes will 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 17 2 Configuring a DHCP Server You can configure a DHCP server using the configuration file etc dhcpd conf DHCP also uses the file var 1lib dhcp dhcpd leases to store the client lease database Refer to Section 17 2 2 for more information 17 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 all clients or 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 depreciated If you want to keep the same behavior add the following line to t
158. ed as an xinetd service Chapter 13 Controlling Access to Services 117 chkconfig list finger finger on As shown above if xinetd is running finger is enabled If you use chkconfig list to query a service in etc rc d you will see the service s settings for each runlevel like the following chkconfig list anacron anacron O off l off 2 o0n 3 0n 4 on 5S on 6 o0ff More importantly chkconfig can be used to set 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 command chkconfig level 345 nscd off See the chkconfig man page for more information on how to use it warning Services managed by xineta are immediately affected by chkconfig For example if xinetd is running finger is disabled and the command chkconfig finger on s executed finger is im mediately enabled without having to restart xinetd 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 start or restart to start or restart the service 13 6 Additional Resources For more information on xinetd refer to the following resources 13 6 1 Installed Documentation man ntsysv The ntsysv man page man chkconfig The chkconfi
159. el Modules As you can see in Example 30 1 1smod displays the size use count and referring modules for each module currently loaded To load a kernel module you can use the command sbin insmod followed by the kernel module name By default insmod tries 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 other modules must be loaded first for it to load To resolve these dependencies you can either load the module dependencies and then load the module you want or you can use the command sbin modprobe followed by the module name to load the module along with its dependencies For example the command sbin modprobe tulip loads the tulip network interface module To unload kernel modules use the command sbin rmmod followed by the module name The rmmod utility will only unload modules that are not in use and that are not a dependency of other modules in use For example the command sbin rmmod tulip unloads the tulip network interface module Another useful kernel module utility is modinfo You can use the command sbin modinfo to display information about a kernel module The general syntax is sbin modinfo options lt module gt Options include a that displays a brief description of the module and p that lists the parameter
160. el of Linux expertise The easiest way to deny access to a service is to simply turn it off Both the services managed by xinetd which we will talk about more later in this section and the services in the etc rc d hierarchy 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 you to start stop and restart each service 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 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 iptable
161. els 016 In this example you would be setting the services for runlevels 0 1 and 6 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 The F1 key will pop up a short description of each service A waists Changes do not take effect immediately after using ntsysv 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 start or restart to start or restart the service If you want to start or stop a service which is managed by xinetd use the command service xinetd restart 13 5 chkconfig The chkconfig command can also be used to activate and deactivate services If you use the chk config list command you will see a list of system services and whether they are started on or stopped off in runlevels 0 6 at the end of the list you will see a section for the services managed by xinetd If you use chkconfig list to query a service managed by xinetd you will see whether the xinetd service is enabled on or disabled off For example the following command shows that finger is enabl
162. em Switcher redhat switchmail See Mail Transport Agent Switcher redhat switchmail nox See Mail Transport Agent Switcher rescue mode 75 definition of 75 from CD diskette 75 using 75 utilities available 77 resize2fs 16 rmmod 232 RPM 235 additional resources 244 book about 245 checking package signatures 241 dependencies 237 design goals 235 determining file ownership with 242 documentation with 243 file conflicts resolving 237 finding deleted files with 242 freshen 239 freshening packages 239 GnuPG 241 graphical interface 247 installing 236 with Package Management Tool 248 md5sum 241 preserving configuration files 239 querying 240 querying for file list 244 querying uninstalled packages 243 tips 242 uninstalling 238 with Package Management Tool 249 upgrading 239 using 236 verifying 240 website 245 RPM Package Manager See RPM RSA keys generating 121 RSA Version keys generating 122 runlevels 113 275 S Samba 131 additional resources 133 configuration 131 smb conf 131 encrypted passwords 132 pam_smbpass 132 reasons for using 131 share connecting to 133 connecting to with Nautilus 133 syncing passwords with passwd 132 with Windows 2000 132 with Windows NT 4 0 132 scp See OpenSSH security 113 security level See Security Level Configuration Tool Security Level Configuration Tool customize incoming services 106 customize trusted devices 106 i
163. ences 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 25 Gathering System Information v File Edit View Search View My Processes Process Name User Memory CPU jio bonobo activation server tfox 23MB 0 27059 fam tfox 1 5MB 0 27049 gconfd 2 tfox 4 3MB 0 27032 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 v bash tfox 1 4MB 0 27863 gnome system monitor tfox 89MB 1 28130 metacity tfox 66MB 0 27041 mixer_applet2 tfox 83MB 0 27075 mozilla bin tfox 20 6 MB 0 27650 nautilus tfox 16 8 MB 0 27053 More Info gt gt JEI Figure 25 1 GNOME System Monitor 25 2 Memory Usage 191 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
164. er will be used in a production environment you will 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 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 To see a list of CAs click on the Security button on your Web browser toolbar or on the padlock icon at the bottom left of the screen then click on Signers to see a list of certificate signers from whom your browser will accept certificates You can also search the Web for CAs Once you have decided upon a CA you will 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 will send you a digital certificate 5 Install this certificate on your Web 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 19 6 for instructions on how to generate a
165. ert word select the word from the list and click Delete Log Files Alerts Alerts failed denied rejected oops segfault segmentation Show alert icon for the following key words Add Delete X Close Figure 28 3 Alerts 224 Chapter 28 Log Files 3 redhat Chapter 29 Upgrading the Kernel The Red Hat 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 pass a rigorous set of quality assurance tests Official Red Hat Linux kernels are packaged in RPM format so that they are easy to upgrade and verify For example the kernel RPM package creates the initrd image it is not necessary to use the mkinitrd command after installing a different kernel if you install the kernel from the Red Hat RPM package It also modifies the boot loader configuration file to include the new kernel if either GRUB or LILO is installed You do need to set the new kernel as the default kernel to boot This chapter discusses the steps necessary to upgrade the kernel on an x86 system only T Building your own custom kernel is not supported by the Red Hat Linux Installation Support Team For more information on building a custom kernel from the source code refer to Appendix A 29 1 The 2 4 Kernel Red Hat Linux ships with a custom 2 4 kernel which offer
166. es a digital certificate from a Certificate Authority CA SSL handles the encrypted communications and the mutual authentication between browsers and your secure Web server The CA approved digital certificate provides authentication for your secure Web server the CA puts its reputation behind its certification of your organization s identity When your browser is communicating using SSL encryption you will see the https prefix 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 you will use public cryptography to create a public and private key pair In most cases you will send your certificate request including your public key proof of your company s identity and payment to a CA The CA will verify the certificate request and your identity and then send back a certificate for your secure Web server A sec
167. es 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 7 4 1 1 Creating Software RAID Partitions Read Chapter 3 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 an existing partition to use Chapter 7 Kickstart Configurator 65 Mount Point 5i File System Type software RAID v Size MB 2048 1S Additional Size Options Fixed size Grow to maximum of MB 1 ial Fill all unused space on disk recommended swap size _ Force to be a primary partition asprimary lt Make partition on specific drive ondisk Drive sdal for example hda or sdc Use existing partition onpart Partition for example hdal or sdc3 x Format partition X Cancel 2 OK Figure 7 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 th
168. es in misc export on shadowman example com 15 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 mounted 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 126 Chapter 15 Network File System NFS 15 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 dire
169. f Intel Corporation Itanium and Celeron are trademarks of Intel Corporation AMD AMD Athlon AMD Duron and AMD K6 are 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 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 Introduction esin A a oE A N SOTE E E steven sebessasearscessesestieVecesacos vii 1 Changes to This Mantal eeneninnaocin n a e a E o EE EE ES vii 2 Document Conventions yelas srei n es e EREE EA EEY EAK eSEE KEE EEs viii 3 Moreto Come ssr us sel at rece agp a acs Vas en S SN EEEE E EEEE Ta ap DSN a xi 3 1 Send in Your Feedback 4 Sign Up for Support TL File Systems scsssssssssssssssscsssessssssscssssssessssececssssnssssesssssesessesssosesvasesssessessesssosssesuesssasessevevssesees iii 1 The ext3 File System 1 1 Features of ext3 1 2 Creating an ext3 File System 1 3 Converting to an ext3 File System 1 4 Reverting to an ext2 File System a 2 SWAP SPace oo cesses 19 2 1 What is Swap Space 2 2 Adding Swap Space 2 3
170. figuration 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 7 12 Also select the amount of video RAM the selected video card has from the Video Card RAM pulldown menu These values will be used by the installation program to configure the X Window System 70 Chapter 7 Kickstart Configurator File Help Basic Configuration X Configuration Installation Method Configure the X Window System Boot Loader Options General Video Card Monitor Partition Information C Probe for video card Network Configuration a speu e uiae uuu x Authentication Magic Pro MP 740DVD Firewall Configuration Matrox Comet Matrox Marvel II Package Selection Matrox Millennium Pre Installation Script Matrox Millennium G200 Post installation Script 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 105D with GenDAC Miro Crystal 12SD Miro Crystal 16S Video Card RAM B2 MB Figure 7 12 X Configuration Video Card 7 8 3 Monitor After configuring the video card click on the Monitor tab shown in Figure 7 13 Probe for monitor is selected by default Accept this default if y
171. g GnuPG you can encrypt your data and correspondence and authenticate your correspondence by digitally signing your work GnuPG is also capable of decrypting and verifying PGP 5 x Because GnuPG is compatible with other encryption standards your secure correspondence will prob ably be compatible with email applications on other operating systems such as Windows and Macin tosh GnuPG uses public key cryptography to provide users with a secure exchange of data In a public key cryptography scheme you generate two keys a public key and a private key You exchange your public key with correspondents or with a keyserver you should never reveal your private key Encryption depends upon the use of keys 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 key 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 isan Remember that your public key can be given to anyone with whom you want to communicate securely but you must never give away your private key For the most part cryptography is beyond the scope of this publication volumes have been written about the subject In this chapter h
172. g man page man xinetd The xinetd man page man xinetd conf The man page for the xinetd conf configuration file man 5 hosts_access The man page for the format of host access control files in section 5 of the man pages 13 6 2 Useful Websites http www xinetd org The xinetd webpage It contains a more detailed list of features and sample configuration files 118 Chapter 13 Controlling Access to Services redhat Chapter 14 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 14 1 Why Use OpenSSH If you use OpenSSH tools you are enhancing the security of your machine All communications using OpenSSH tools including passwords are encrypted Telnet and ftp use plaintext 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 mach
173. gure 26 9 Enter a unique name for the printer in the Queue Name text field The printer name cannot contain spaces and must begin with a letter a through z or A through Z The valid characters are a through z A through Z O through 9 and _ Select Novell Printer from the Queue Type menu and click Next 204 Chapter 26 Printer Configuration Set the Print Queue Name and Type Enter the Queue s name and select the Queue s Type Valid names can contain the characters a z A Z 0 9 and __ They must begin with letters Queue Name test4 Queue Type Local Printer LOCAL Unix Printer LPD Windows Printer SMB NCP JETDIRECT amp X Cancel Back Figure 26 9 Adding an NCP Printer Text fields for the following options appear below the Queue Type menu as shown in Figure 26 10 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 Configure a Novell Print Queue Configure the remote server and queue of your NCP printer Server User servername example com username Queue Password queue wenewewnenneel X Cancel Back Figure 26 10 Choosing the Print Server The next step is to select the typ
174. gure 9 3 Creating a RAID Array 82 Chapter 9 Software RAID Configuration 3 redhat Chapter 10 LVM Configuration LVM can be configured during the graphical installation of Red Hat Linux or during a kickstart in stallation You can use the utilities from the 1vm package to create your LVM configuration but these instructions will focus on using Disk Druid during the Red Hat Linux installation to complete this task Read Chapter 4 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 hrote 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 the Red Hat Linux installation 1 On the Disk Partitioning Setup screen select Manually partition with Disk Druid 2 Select New 3 You will not be able to enter a mount point you will be able to do that once you have created your volume group 4 Select physical volume LVM from the Filesystem Type pull down menu as shown in Figure Add Partition Mount Point Not Applicable El File System Type physical volume LVM X Z hda 19469MB Maxtor 52049H3 AAS Dies O hdb 19469MB Maxtor 52049H3 Size MB 100
175. h the command rm For example to remove the partition with minor number 3 rm 3 The changes start taking place as soon as you type 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 warning 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 create the partition parted dev hda View the current partition table to determine the minor number of the partition to remove as well as the start and end points for the partition print Deining 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 After resizing the partition use the print command to confirm that the partition has been resized correctly is the correct parti
176. hat 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 18 2 3 Environment Variables 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 directives for this module 148 Chapter 18 Apache HTTP Server Configuration Site Configuration Set for CGI Scripts Eee Environment Variable Value act Directorie
177. he default group is also apache 18 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 Chapter 18 Apache HTTP Server Configuration 155 Main Virtual Hosts Server Performance Tuning Servers Max Number of Connections 150 Connections Connection Timeout 300 Allow unlimited requests per connection Max requests per connection 100 Requests per Connection O Allow Persistent Connections Timeout for next Connectio S Dox X Cancel B Heip Figure 18 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 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
178. he output will look similar to the following gpg key F78FFE84 public key imported gpg Total number processed 1 gpg imported 1 To check that the process was successful use the gpg list keys command you should see your newly imported key listed on your keyring When you import a public key you add that key to your keyring a file in which public and secret keys are kept Then when you download a document or file from that entity you can check the validity of that document against the key you added to your keyring B 7 What Are Digital Signatures Digital signatures can be compared to your written signature Unlike traditional correspondence in which it might be possible to tamper with your written signature digital signatures can not be forged That is because the signature is created with your unique secret key and can be verified by your recipient using your public key A digital signature timestamps a document essentially that means that the time you signed the doc ument is part of that signature So if anyone tries to modify the document the verification of the signature will fail Some email applications such as Exmh or KDE s KMail include the ability to sign documents with GnuPG within the application s interface Two useful types of digital signatures are clearsigned documents and detached signatures Both types of signatures incorporate the same security of authenticity without requiring your recipient to dec
179. he 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 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 deviceprobe optional Forces a probe of the PCI bus and loads modules for all the devices found if a module is available driverdisk optional Driver disks can be used during kickstart installations You will need to copy the driver disk s contents to the root directory of a partition on the system s hard drive Then you will 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 lt partition gt Partition containing the driver disk type Filesystem type for example vfat ext2 or ext3 Chapter 6 Kickstart Installations 43 firewall optional This option corresponds to the Firewall Configuration screen in the installation program firewall lt securitylevel gt trust lt incoming gt port lt securitylevel gt Replace with one of the following levels of security high e medium e disabled trust List
180. he 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 Read the dhcpd conf man page for details about the different modes 136 Chapter 17 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 option 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 Oi If you change the configuration file the changes will not take effect until you restart the DHCP daemon with the command service dhcpd restart In Example 17 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 17 1 you can declare a subnet You must include a subnet declarat
181. he user would be prompted during a typical 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 6 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 7 for details ote 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 autostep optional Similar to interactive except it goes to the next screen for you It is used mostly for debug ging auth or authconfig required Sets up the authentication 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 en
182. hernet parameter within a host declaration As demonstrated in Example 138 Chapter 17 Dynamic Host Configuration Protocol DHCP 17 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 you can also use the optional parameter host name 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 17 5 Static IP Address using DHCP rip You can use the sample configuration file in Red Hat Linux 8 0 as a starting point and then add your own custom configuration options to it Copy it to its proper location with the 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 you are using For a complete list of option statements and what they do refer to the dhcp options man page 17 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
183. how long your 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 MaxkKeepAliveRequests 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 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 th
184. hrough your firewall so that remote hosts can connect directly to your machine to deliver mail enable this option You do not need to enable this if 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 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 You need to install the wu ftpd and possibly the anonftp package for this option to be useful Other ports You can allow access to ports which are not listed here by listing them in the Other ports field Use the following format port protocol For example if you want to allow IMAP access through your firewall you can specify imap tcp You can also explic itly specify numeric ports to allow UDP packets on port 1234 through the firewall enter 1234 udp To specify multiple ports separate them with commas 108 Chapter 12 Basic Firewall Configuration You must have the iptables service enabled and running to activate the security level Refer to Section 12 3 for details 12 2 GNOME Lokkit GNOME Lokkit allows you to configure firewall settings for an average user by constructing basic iptables networking rules Instead of having to write the rules this program asks you a series of questions about how you use your system
185. iQuest V95 ViewSonic OptiQuest VA656 ViewSonic P655 ViewSonic P775 ViewSonic P795 Specify hsync and vsync instead of monitor Horizontal Sync Hz Vertical Sync kHz Figure 7 13 X Configuration Monitor 7 9 Package Selection Eile Help Installation Method Boot Loader Options Partition Information Network Configuration Authentication Firewall Configuration X Configuration Pre Installation Script Post Installation Script Basic Configuration Package Selection Select packages to install Automatically Resolve Dependencies O Ignore Dependencies X Window System GNOME Desktop Environment KDE Desktop Environment Applications Editors Engineering and Scientific Graphical Internet Text based Internet Office Productivity Sound and Video Graphics Games and Entertainment Authoring and Publishing Servers Server Configuration Tools Web Server Mail Server Windows File Server Figure 7 14 Package Selection 71 72 Chapter 7 Kickstart Configurator The Package Selection window allows you to choose which package groups to install There are also options to resolve package dependencies automatically and to ignore package depen dencies Currently Kickstart Configurator does not a
186. ic Keys nenret t E B 6 Importing a Public Key ssnsti se iisisti titiis ears iio EE B 7 What Are Digital Signatures B 8 Additional Resources sissien sot trasine istisi S INLA a O EIA E Ea 3 redhat Welcome to the Official Red Hat Linux Customization Guide Introduction The Official Red Hat Linux Customization Guide contains information on how to customize your Red Hat 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 Determining information about your system Upgrading your kernel This manual is divided into the following main categories Installation Related Reference Network Related Reference System Configuration Package Management This guide assumes you have a basic understanding of your Red Hat Linux system If you need ref erence material which covers more basic issues such as configuring your desktop or playing audio CD ROMs please refer to the Official Red Hat Linux Getting Started Guide If you need more ad vanced documentation such as an overview of the Red Hat Linux filesystem please refer to the Official Red Hat Linux Reference Guide HTML and PDF versions of the Official Re
187. ide 2nd edition by Ben Laurie and Peter Laurie O Reilly amp Associates Inc 168 Chapter 19 Apache HTTP Secure Server Configuration 3 redhat r Chapter 20 BIND Configuration This chapter assumes that you have 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 Bind Configuration Tool redhat config bind to configure basic BIND server zones The Bind Configuration Tool creates the etc named conf configuration file and the zone configuration files in the var named directory each time you apply your changes Ocak Do not edit the etc named conf configuration file Bind Configuration Tool generates this file after you apply your changes If you want to configure settings that are not configurable using Bind Configuration Tool add them to etc named custom The Bind Configuration Tool requires the X Window System and root access To start the Bind Configuration Tool go to the Main Menu Button on the Panel gt Server Settings gt Domain Name Service or type the command redhat config bind at a shell prompt for example in an XTerm or GNOME terminal File Help gt 8 0 0 127 in addr arpa Edit Delete Add Record Figure 20 1 Bind Configuration Tool The Bind Configuration Tool configures the default zone directory to be var named All zone files specified are relative to this di
188. ific directories click the Add button beside the Directory list box The window shown in Figure 18 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 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 Full IP address Allow access to a specific IP address 150 Chapter 18 Apache HTTP Server Configuration A subnet Such as 192 168 1 0 255 255 255 0 A network CIDR specification such as 10 3 0 0 16 Order Options Let all hosts access this directory options Process Deny list before Allow list Z ExecCGI Process Allow list before Deny list FollowSymLinks Includes Deny List IncludesNOEXEC v Deny access from all hosts al Deny hosts from SymLinksIlfOwnerMatch Allow List Allow access from all hosts a Allow hosts from 192 168 1 0 255 255 255 0 Let htaccess files override directory options Directory var www html testing Browse B Heip Pox amp Cancel Figure 18 7 Directory Settings If you check the Let htaccess f
189. iles override directory options the configuration directives in the htaccess file take precedence 18 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 vww your_domain com and http www your_second_domain 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 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 HTTP Configuration Tool includes a default virtual host as shown in Figure 18 8 Chapter 18 Apache HTTP Server Configuration 151 Main Virtual Hosts Server Performance Tuning Virtual Hosts Name Address Add Default Virtual Host Default virtual host Edit Delete Edit Default Settings 9 oK X Cancel B Heip
190. ilter the mail from diskcheck For example ifmailFrom Disk Usage Monitor is specified email will be sent to the system administrator with the sender Disk Usage Monitor mailProg Specify the mail program to use to send email alerts For example if mailProg usr sbin sendmail is specified Sendmail will be used as the mail program You do not have to restart a service if you change the configuration file because it is read each time the cron task is run You must have the crond service running for cron tasks to be executed To determine if the daemon is running use the command sbin service crond status It is recommended that you start the service at boot time Refer to Chapter 13 for details on starting the cron service automatically at boot time 1 Refer to Chapter 27 for more information on cron 194 Chapter 25 Gathering System Information 25 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 25 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
191. in Figure 20 4 creates the following entry in etc named conf zone Slave example com type slave file slave example com zone masters Li 2e seas 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 After configuring the slave zone click OK to return to the main window as shown in Figure 20 1 From the pulldown menu choose File gt Apply to write the etc named conf configuration file and have the daemon reload the configuration files 174 Chapter 20 BIND Configuration 3 redhat Chapter 21 Mail Transport Agent MTA Configuration A Mail Transport Agent MTA is essential for sending email from a Red Hat Linux system The Mail User Agent MUA such as Mozilla Mail Mutt Pine and Evolution 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 Linux 8 0 provides two MTAs Sendmail and Postfix If both are installed sendmail is the default MTA Mail Transport Agent Switcher allows a user to select either sendmail or post fix as the default MTA for the system To start
192. in 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 command 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 usr share doc will be displayed and you will return to your shell prompt 14 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
193. in the main Printer Configuration Tool window The window shown in Figure 26 2 will appear Click Next to proceed You will then see the screen shown in Figure 26 5 Enter a unique name for the printer in the Queue Name text field The printer name cannot contain spaces and must begin with a letter a through z or A through Z The valid characters are a through z A through Z 0 through 9 and _ Select Unix Printer from the Queue Type menu and click Next Chapter 26 Printer Configuration 201 Set the Print Queue Name and Type Enter the Queue s name and select the Queue s Type Valid names can contain the characters a z A Z 0 9 and __ They must begin with letters Queue Name test2 Queue Type Local Printer LOCAL LPD Windows Printer SMB Novell Printer NCP JetDirect Printer JETDIRECT I amp X Cancel Back Figure 26 5 Adding a Remote Printer Text fields for the following options appears as shown in Figure 26 6 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 By default the Strict RFC1179 Compliance option is not chosen If you are having problems printing to a non Linux 1pd queue choose this option to disable enhanced LPRng printing features Click Next to continue Configure a Unix Print Queue Configure the server
194. inal 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 Preparing AEAEE AE AE AE AE AE AE ARATE AE AE AE AE RAH AE AE AEAEE H E E 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 Chapter 31 Package Management with RPM 239 31 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 1386 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 will work even when there are no previous versions of the package installed 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
195. ine 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 14 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 configura tion file installed with Red Hat Linux 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 that 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 13 for information on how to manage services If you reinstall a Red Hat Linux system and clients connected to it before the reinstall with any of the OpenSSH tools after the reinstall the client users will see the following message CO AAEEECAEEEAEEEEEAEEEEAAEEEEEEAEEEEEEEEEEEEEEEEEEEREEEEEEE WARNING
196. inetd d directory with the command 1s etc xinetd d Chapter 13 Controlling Access to Services 115 13 3 Services Configuration Tool Services Configuration Tool is a graphical application developed by Red Hat to configure which SysV services in etc rc d init d 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 Services Configuration Tool from the desktop go to the Main Menu Button on the Panel gt Server Settings gt Services or type the command redhat config services at a shell prompt for example in an XTerm or a GNOME terminal File Actions Edit Runlevel Help 9 a4 0 Save Cancel Exit Start Currently Running in Runlevel 5 Editing Runlevel 5 LJ Oayume uup a C dbskkd cdb a C dhepd C dhcrelay O echo C echo udp x The comsat server is used by the biff client to tell whe n new mail is present You must enable xinetd to use this service Figure 13 1 Services Configuration Tool Services Configuration Tool displays the current runlevel as well as which runlevel you are currently editing To edit a different runlevel select Edit Runlevel from the pulldown menu and select runlevel 3 4 or 5 Refer to Section 13 1 for a description of runlevels Services Configuration Tool lists the services from etc rc d init d as well as the services controlled by
197. ing 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 ethl 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 specified services through the firewall dhcp gt ssh telnet S smep e http Ep port You can specify that ports be allowed through the firewall using the port protocol format For example if you wanted to allow IMAP access through your firewall you can specify imap tcp You can also specify numeric ports explicitly for example to allow UDP pack ets on port 1234 through specify 1234 udp To specify multiple ports separate them by commas 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 cdrom Install from the first CD ROM drive on the system 44 Chapter 6 Kickstart Installations 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 dir Directory containing the RedHat directory of the installation tree For example harddrive partition hdb2 dir tmp install tree
198. installation Select Main Menu Button gt System Tools gt Red Hat Network on your desktop Execute the command up2date from a shell prompt 2 Log in to RHN at http rhn redhat com and entitle the system to a service offering Everyone receives a free Red Hat Network account for one system Additional accounts can be purchased 3 Start scheduling updates through the RHN website or download and install Errata Updates with the Red Hat Update Agent For more detailed instructions read the Red Hat Network User Reference Guide available at http www redhat com docs manuals RHNetwork 252 Chapter 33 Red Hat Network Appendixes 3 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 In the past you had to recompile the kernel if you added new hardware on your system In other words the kernel was static Improvements in the Linux 2 0 x kernels allowed for many hardware drivers to be modularized into components that are loaded on demand However major problems existed when users had multiple kernels that had been compiled for different configuration options on their system for example SMP versus UP kernels Further Linux 2 4 x kernel modularization adva
199. instead of make genkey to create the key Use the following command usr bin openssl genrsa 1024 gt etc httpd conf ssl key server key to create your key Then use this command chmod go rwx etc httpd conf ssl key server key to make sure that the permissions are set correctly on your key After you use the above commands to create your key you will not need to use a password to start your secure Web server Chapter 19 Apache HTTP Secure Server Configuration 163 Efon Disabling the password feature for your secure Web server is a security risk It is NOT recommend that you disable the password feature for your secure Web server The problems associated with not using a password are directly 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 will appear to be from your Web 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 the secure Web server s password may seem unnecessary However since your secure Web server should not need to be re booted very often the extra security provided by entering a password is a worthwhile effo
200. iods instead of exact times refer to Section 27 2 To schedule one time tasks refer to Section 27 3 To use the cron service you must have the vixie cron RPM package installed and the crond service must be running To determine if the package is installed use the rpm q vixie croncom mand To determine if the service is running use the command sbin service crond status 27 1 1 Configuring Cron Tasks The main configuration file for cron etc crontab contains the following lines 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 42 4 1 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 will not be 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 t
201. ion 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 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 which requests a document from your Web server Resolving the IP address means t
202. ion 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 Official Red Hat Linux box To read more about technical support for Official Red Hat Linux refer to the Getting Technical Sup port Appendix in the Official Red Hat Linux Installation Guide Good luck and thank you for choosing Red Hat Linux The Red Hat Documentation Team Introduction File Systems 3 redhat Chapter 1 The ext3 File System Beginning with the release of Red Hat Linux 7 2 the default file system changed from the venerable ext2 format to the journaling ext3 file system 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
203. ion for every subnet in your network If you do not the DHCP server will fail 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 2547 option subnet mask E Ao e TEE SA E option domain name example com option domain name servers aD A E sT R option time offset 18000 Eastern Standard Time range 192 168 1 10 192 168 1 100 Example 17 1 Subnet Declaration All subnets that share the same physical network should be declared within a shared network dec laration as shown in Example 17 2 Parameters within the shared 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 17 Dynamic Host Configuration Protocol DHCP 137 subnet 192 168 1 32 netmask 255 255 255 0 parameters for subnet range 192 168 1 33 192 168 1 63 Example 17 2 Shared network Declaration As
204. ion 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 This is ignored if hsync or vsync is provided If no monitor information is provided the installation program tries to probe for it automatically 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 52 Chapter 6 Kickstart Installations 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 a
205. ion will change in the list below the map Click OK to apply the changes and exit the program If your system clock is set to use UTC select the System clock uses UTC option UTC stands for the universal time zone also known as Greenwich mean time GMT Other time zones are determined by adding or subtracting from the UTC time 3 redhat Chapter 24 User and Group Configuration User Manager allows you to view modify add and delete local users and groups To use User Manager you must be running the X Window System have root privileges and have the redhat config users RPM package installed To start 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 File Preferences Help amp amp amp Add User Add Group Properties Delete Help Refresh Search filter Apply filter User Name User D v Primary Group Full Name Login Shell Home Directory bfox 500 bfox Brent Fox bin bash home bfox tfox 501 tfox Tammy Fox bin bash home tfox Users Groups Figure 24 1 User Manager To view a list of all local users on the system click the Users tab To view a list of all local groups on the system click the Groups tab If you need to find a specific user or group type the first few letters of the name in the Filter by fie
206. irectory gt directive Chapter 18 Apache HTTP Server Configuration 149 Site Configuration Default Directory Options Edit Logging Environment Variables ExecCGI FollowSymLinks Includes IncludesNOEXEC m Indexes SymLinksIfOwnerMatch Directories Directory Add m Delete g Help Box amp Cancel Figure 18 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 is 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 spec
207. irectory 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 eth device use the command ks nfs lt server gt lt path gt ksdevice ethl at the boot prompt redhat Chapter 7 Kickstart Configurator Kickstart Configurator allows you to create a kickstart file using a graphical user interface so that you do not have to remember the correct syntax of the file After choosing the kickstart options click the Save File button verify the options you have chosen and save the kickstart file to a desired location 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 preview your current selections 7 1 Basic Configuration File Help Basic Configuration Basic Configuration required Installation Method Language English v Boot Loader Options Key
208. irtual 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 If an Apache HTTP Server is not configured 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 Addresses Refer to Section 18 1 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 18 9 The SSL Configuration section is pre configured with the dummy digital certificate The digital certificate provides authentication for your secure Web server and iden tifies the secure server to client Web browsers You must purchase your own digital certificate Do not
209. is is not specified the log is written to var log messages e cf filename Specify the location of the configuration file The default location is etc dhepd conf 1f filename 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 1lib dhcp dhcpd leases q Do not print the entire copyright message when starting the daemon 17 2 4 DHCP Relay Agent The DHCP Relay Agent dhcrelay allows you to relay 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 140 Chapter 17 Dynamic Host Configuration Protocol DHCP 17 3 Configuring a DHCP Client The first step for configuring a DHCP client is to make sure the kernel re
210. is the version specified in the Makefile In the example it would be lib modules 2 4 18 7 95custom kernel drivers 12 Use make install to copy your 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 sbin new kernel pkg script that builds a new initrd image and adds new entries to the boot loader configuration file If you have a SCSI adapter and you compiled the SCSI driver as a module or if you built your kernel with ext3 support as a module the default in Red Hat Linux the initrd image is required 13 Even though the initrd image and boot loader modifications are made for you you should verify that they were done correctly Refer to Section A 2 and Section A 3 for details A 2 Making an initrd Image An initrd image is needed to load a SCSI module at boot time or if you compiled the kernel with ext3 support as a module To verify that a new initrd file was created view the contents of the boot directory You should see the file initrd 2 4 18 7 95custom img where 2 4 18 7 95customis the name of the kernel you just built If it does not exist use the sbin mkinitrd shell script to create it sbin mkinitrd boot initrd 2 4 18 7 95custom img 2 4 18 7 95custom In the above example boot initrd 2 4 18 7 95custom img is the file name of the new ini trd image 2 4 18 7 95custom is the kernel whose modules from 1ib m
211. ization Name Organizational Unit Name Common Name and Email address All of these should be self explanatory but you need to follow these guidelines 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 will reject CSRs which include information they perceive as invalid For Common Name make sure you type in the real name of your secure Web 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 will 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 When you have finished entering your information the file etc httpd conf ssl csr server csr will be created This file is your
212. kages 248 removing packages 249 packages dependencies 237 determining file ownership with 242 finding deleted files from 242 freshening with RPM 239 installing 236 with Package Management Tool 248 locating documentation for 243 obtaining list of files 244 preserving configuration files 239 querying 240 querying uninstalled 243 removing 238 with Package Management Tool 249 tips 242 upgrading 239 verifying 240 pam_smbpass 132 pam_timestamp 181 parted 29 creating partitions 30 274 overview 29 removing partitions 32 resizing partitions 33 selecting device 30 table of commands 29 viewing partition table 30 partition table viewing 30 partitions creating 30 formating mkfs 31 labeling e2label 32 making mkpart 31 removing 32 resizing 33 viewing list 30 PCI devices listing 194 physical extent 84 physical volume 27 83 postfix 175 printconf See printer configuration printer configuration 197 cancel print job 212 command line options 210 add a printer 210 remove a printer 211 restore configuration 210 save configuration 210 creating an alias 208 CUPS printing system 212 configuration interface 213 default printer 208 delete existing printer 208 driver options 209 Assume Unknown Data is Text 209 Convert Text to Postscript 209 Effective Filter Locale 209 Media Source 209 Page Size 209 Prerender Postscript 209 Send End of Transmission EOT 209 Send F
213. lation program will automatically select the closest size in units of 4 MBs It is not recommended that you change this 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 10 3 will appear Make Logical Volume Mount Point home x x Eile System Type ext3 Logical Volume Name LogVol00 Size MB 2048 Max size is 4080 MB X cancel Cancel Box K Figure 10 3 Creating a Logical Volume Repeat these steps for each volume group you want to create Qrip You may want to leave some free space in the logical volume group so you can expand the logical volumes later redhat Onine Heip Partitioning Disk Setup crn evn eom uate Ode arn eat fase Choose where you would like Red Hat Poma Linux to be installed Drive idevhdb Geom 248225563 Model Maxtor 5204943 lryou do not know how to partition your en system or if you need help with using the eue iona manual paritioning tools refer to the Red Hat Linux Installation Guide If you used automatic partitioning you can ER oa TT ae Ga either accept the current partition settings sad Ed Delete set Al E click Next or modify the setup usi
214. lation tree For example if your NFS server contains the directory mirrors redhat i386 RedHat enter mirrors redhat i386 for the NFS directory FTP Choose this option if you wish to install Red Hat Linux from an FTP server Two text entry boxes for the FTP server and FTP directory will appear Enter the fully qualified domain name or IP address of the FTP server For the FTP directory enter the name of the FTP direc tory that contains the RedHat directory For example if your FTP server contains the directory mirrors redhat i386 RedHat enter mirrors redhat i386 for the FTP directory HTTP Choose this option if you wish to install Red Hat Linux from an HTTP server Two text entry boxes for the HTTP server and HTTP directory will appear Enter the fully qualified domain name or IP address of the HTTP server For the HTTP directory enter the name of the HTTP directory that contains the RedHat directory For example if your HTTP server contains the directory mirrors redhat i386 RedHat enter mirrors redhat i386 for the HTTP directory Hard Drive Choose this option if you wish to install Red Hat Linux from a hard drive Two text entry boxes for hard drive partition and hard drive directory will appear 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 Enter the hard drive partition that c
215. lay it is highly recommended that you configure Sendmail to prevent it You must have the iptables service enabled and running to activate the firewall Refer to Section 12 3 for details 12 3 Activating the iptables Service The firewall rules will only be active if the iptables service is running To manual 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 You can also use Serviceconf to activate iptables See Section 13 3 You can not run the ipchains service along with the iptables service To make sure the ipchains service is disabled execute the command sbin chkconfig level 345 ipchains off 112 Chapter 12 Basic Firewall Configuration redhat Chapter 13 Controlling Access to Services Maintaining security on your Red Hat Linux system is extremely important One way to manage security on your system is to carefully manage access to system services 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 this will minimize your exposure to possible bug exploits There are several different methods for managing access to system services You must decide which method you would like to use based on the service your system s configuration and your lev
216. ld Press Enter or click the Apply filter button The filtered list will be displayed To sort the users or groups click on the column name The users or groups will be sorted by the value of that column Red Hat Linux reserves user IDs above 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 pull down menu For more information on users and groups refer to the Official Red Hat Linux Reference Guide 24 1 Adding a New User To add a new user click the New User button A window as shown in Figure 24 2 will appear 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 rip 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 word and that the password be a combination of letters numbers and special characters 186 Chapter 24 User and Group Configuration Select a login shell If you are not sure which shell to select 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
217. le Common 2 New Devices Hardware Hosts DNS You may configure network devices associated with 4 o physical hardware here Multiple logical devices can be associated with a single piece of hardware Profile Status Device Nickname Type Add pppo dfd D Ea copy Delete Activate t gt O Hep Y Apply X Close Figure 11 8 xDSL Device Be sure to click Apply 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 as seen by its Inactive status To activate the device select it from the device list and click the Activate button 96 Chapter 11 Network Configuration 11 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 rip For more information on using token ring under Linux refer to the Linux Token Ring Project website available at http www linuxtr net To add a token ring connection follow these steps 1 Click the Devices tab 2 Click the Add button 3 Select Token Ri
218. le by the user the server runs as if you want to write the core dumps to disk for debugging purposes 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 warning 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 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 T
219. led to the user Use the command atq to view pending jobs Refer to Section 27 3 3 for more information Usage of the bat ch command can be restricted Refer to Section 27 3 5 for details 27 3 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 is in the format job number date hour job class and username Users can only view their own jobs If the root user executes the atq command all jobs for all users are displayed 27 3 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 27 1 at and batch Command Line Options 27 3 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 220 Chapter 27 Automated Tasks commands The format of both access control files is one username on each line Whitespace is not 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 ac
220. ll 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 During the installation of Red Hat Linux GnuPG is installed by default That way you can immedi ately start using GnuPG to verify any packages that you receive from Red Hat First you will need to import Red Hat s public key 242 Chapter 31 Package Management with RPM 31 3 1 Importing Keys To verify official 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 installed for RPM verification execute the command rpm qa gpg pubkey For the Red Hat key the output will include 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 31 3 2 Verifying Signature of Packages To check the GnuPG signature of an RPM file after importing the builder s GnuPG key use the f
221. llow you to select individual packages To install indi vidual packages modify the packages section of the kickstart file after you save it 7 10 Pre Installation Script File Help Basic Configuration Post installation Script Installation Method Waming 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 CI 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 Figure 7 15 Pre Installation Script You can add commands to run on the system immediately after the kickstart file has been parsed and before the installation begins If you have configured the network in the kickstart file the network is enabled before this section is processed If you would like to include a pre installation script type it in the text area If you want to specify a scripting language to use to execute your script click the Use an interpreter button and enter the interpreter in the text box beside the button For example usr bin python2 2 can be specified for a Python script This option corresponds to using Spre interpreter usr bin python2 2 in your kickstart file Gleaution Do not include the spre command It will be added for you Chapter 7 Kickstart Configu
222. lowed by a colon and a number for example eth0 1 They are useful if you want to have more than one IP address for a system but the system only has one network card If you have configured a device such as ethO click the Add button in Network Administration Tool to create an alias for the device Select the network device and configure the network settings The alias will appear in the device list with a device name followed by a colon and the alias number warning 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 11 19 shows an example of one alias for the ethO device Notice the eth0 1 device the first alias for ethO 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 Active Profile Common z New Rename Remove Devices Hardware Hosts DNS j 2 You may configure network devices associated with 4 o physical hardware here Multiple logical devices can be i associated with a single piece of hardware Profile Status Device Nickname Type Add Active etho etho Ethemet pM AX Active m eth0 1 etho 1 Ethemet
223. m from one of the Red Hat Linux CD ROMs or the Red Hat FTP site available at ftp ftp redhat com a list of mirrors is available at http www redhat com mirrors html Refer to Chapter 31 for information on installing RPM packages 3 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 4 It is important that you begin a kernel build with the source tree in a known condition There fore it is recommended that you begin with the command make mrproper This will re move any configuration files along with the remains of any previous builds that may be scat tered around the source tree If you already have an existing configuration file that works usr src linux 2 4 config and you want to use back it up to a different directory before running this command and copy it back afterward 256 Appendix A Building a Custom Kernel 5 Now you need a configuration file that will determine which components to include in your new kernel If you are running the X Window System the recommended method is to use the command make xconfig Components are listed in different levels of menus and are selected using a mouse You can select Y yes N no or M module After choosing your components click the Save and Exit button to create the configuration file usr src linux 2 4 config and exit the Linux Kernel Configuration program If you want to use the setting
224. mation about your system 189 initrd 257 insmod 232 installation kickstart See kickstart installations LVM 83 software RAID 79 271 Internet connection See network configuration introduction vii ISDN connection See network configuration K kernel building 255 259 custom 255 259 downloading 226 initrd image for 257 large memory support 226 modular 255 modules 231 monolithic 259 multiple processor support 226 upgrading 225 kernel modules listing 231 loading 232 unload 232 kickstart how the file is found 57 Kickstart Configurator 59 post script 73 pre script 72 authentication options 67 basic options 59 boot loader 62 boot loader options 62 firewall configuration 68 installation method selection 60 interactive 60 keyboard 59 language 59 language support 60 mouse 59 network configuration 66 package selection 71 partitioning 63 software RAID 64 preview 59 reboot 60 root password 60 encrypt 60 saving 74 text mode installation 60 time zone 59 X configuration 68 kickstart file include 52 opost 54 pre 53 272 auth 38 authconfig 38 autostep 38 bootloader 40 clearpart 41 creating 38 device 42 deviceprobe 42 diskette based 56 driverdisk 42 firewall 43 format of 37 include contents of another file 52 install 43 installation methods 43 interactive 44 keyboard 44 lang 44 langsupport 45 lilo 45 lilocheck 46 logvol 46
225. mation 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 Remove existing Linux partitions Authentication Preserve existing partitions Pewa Conigurator Initialize the disk label X Configuration Do not initialize the disk label Package Selection 9 4 Devicey Mount Pointy T Format Size MB Pre Installation Script Partition Number RAID Volume YP Post installation Script Add esi Delet RAID Figure 7 4 Partition Information Select whether or not to clear the Master Boot Record MBR You can also choose to remove all the existing partitions remove all the existing Linux partitions or preserve existing partitions You can initialize the disk label to the default for the architecture of the system msdos for x86 and gpt for Itanium Select Initialize the disk label if you are installing on a brand new hard drive 7 4 1 Creating Partitions To create a partition click the Add button The Partition Options window shown in Figure 7 5 will appear Choose 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
226. mmand Chapter 31 Package Management with RPM 245 31 5 2 Useful Websites http www rpm org The RPM website http www redhat com mailing lists rpm list The RPM mailing list is archived here To sub scribe send mail to lt rpm list request redhat com gt with the word subscribe in the sub ject line 31 5 3 Related Books Maximum RPM by Ed Bailey Red Hat Press An online version of the book is available at http www rpm org and http www redhat com docs books 246 Chapter 31 Package Management with RPM redhat Chapter 32 Package Management Tool During installation users select an installation type such as Workstation or Server Software pack ages are installed based on this selection Because people use their computers differently users might want to install or remove packages after installation The Package Management Tool allows users to perform these actions To start the application go to the Main Menu Button on the Panel gt System Settings gt Pack ages or type the command redhat config packages at shell prompt rip The same interface appears if you insert the Red Hat Linux CD ROM 1 into your computer Add or Remove Packages O Desktops X Window System 32 32 Details fi x Install this group of packages to use the base graphical X amp user interface GNOME Desktop Environment 32 32 Details wee GNOME is a powerful graphical user in
227. more information on fdisk refer to man or info page for fdisk If you want to view the system s disk space usage or monitor the disk space usage refer to Section 25 3 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 configure You will see a parted prompt Type help 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 easiest way to achieve this it to boot your system in rescue mode Refer to Chapter 8 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 from and 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 s
228. 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 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 Listen to all addresses D Address 192 168 1 4 f Port 80 2 OK X Cancel Figure 18 2 Available Addresses Chapter 18 Apache HTTP Server Configuration 145 rip 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 18 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 18 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 is used 18 2 1 Site Configuration The default values f
229. mouse 46 network 46 network based 56 57 options 38 package selection specification 52 part 48 partition 48 post installation configuration 54 pre installation configuration 53 raid 49 reboot 50 rootpw 50 skipx 50 text 50 timezone 51 upgrade 51 volgroup 52 what it looks like 37 xconfig 51 zerombr 52 kickstart installations 37 diskette based 56 file format 37 file locations 55 installation tree 57 LVM 46 network based 56 57 starting 57 L loading kernel modules 231 log files 221 See Also Log Viewer description 221 examining 222 locating 221 rotating 221 syslogd 221 viewing 221 Log Viewer alerts 222 filtering 222 log file locations 222 refresh rate 222 searching 222 logical volume 27 85 logical volume group 27 83 Logical Volume Manager See LVM logrotate 221 Ipd 198 LPRng 197 lsmod 231 lspci 194 LVM 27 configuring LVM during installation 83 explanation of 27 logical volume 27 85 logical volume group 27 83 physical extent 84 physical volume 27 83 with kickstart 46 Mail Transport Agent See MTA Mail Transport Agent Switcher 175 Maximum RPM 245 memory usage 191 mkfs 31 mkpart 31 modem connection See network configuration modprobe 232 modules conf 231 mounting NFS file systems 125 MTA Mail Transport Agent Switcher 175 setting default 175 N named conf 169 neat See network configuration netcfg See network configu
230. mponents provided with Red Hat Linux will be 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 plaintext 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 will point you to appropriate places where you can find more in depth documentation on particular subjects This chapter will show you how to install these programs You will 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 Web server The configuration for mod_ssl has moved from etc httpd conf httpd conf to etc httpd conf d ssl 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 19 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 ht
231. n any Red Hat Linux CD ROM for a list of groups Each group as an id uservisiblity 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 1 This option is new to Red Hat Linux 8 0 Chapter 6 Kickstart Installations 53 In most cases it is only necessary to list the desired groups and not individual packages Note that the Core and Base groups are always selected by default so it is not necessary to specify it in the packages section Here is an example packages selection Spackages X Window System GNOME Desktop Environment Graphical Internet Sound and Video galeon 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 file Specify individual packages with no additional characters the galeon line in the example above is an individual package To specify an everything installation to install all packages add the one to the packages section Everything You can also specify which packages not to install from the default package list Games and Entertainment kdegames 6 6 Pre installation Script You can add commands to run on the system immediately afte
232. n or through the RHN website available at http rhn redhat com Red Hat Network saves Red Hat Linux 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 Each Red Hat Network account comes with Errata Alerts Learn when Security Alerts Bug Fix Alerts and Enhancement Alerts are issued for all the systems in your network through the RHN website Automatic email notifications Receive an email notification when an Errata Alert is issued for your system Scheduled Errata Updates Schedule delivery of Errata Updates with optional automatic installa tion 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 To start using Red Hat Network follow these three basic steps 1 Create a System Profile using one of the following methods Registering the system with RHN during the Setup Agent the first time your system boots after
233. nameserver here However you can use the kickstart file s post section described in Section 6 7 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 f Loppy since the installation program will configure the network to find the kickstart file For example network bootproto dhcp device eth0 ip IP address for the machine to be installed gateway Default gateway as an IP address nameserver Primary nameserver as an IP address nodns Do not configure any DNS server netmask Netmask for the installed system hostname Hostname for the installed system 48 Chapter 6 Kickstart Installations part or partition required for installs ignored for upgrades Creates a partition on the system If more than one Red Hat Linux installation exists on the system on different partitions the installation program prompts the user and asks which installation to upgrade warning 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 lt path gt For example usr home swap The partition will be used as swap space To determin
234. ncements allow for multiple kernels to co exist more easily but they can not share modules For information on handling kernel modules see Chapter 30 Unless you are recompiling a customized kernel for your system you will not see many changes in how kernel modules are handled A 1 Building a Modularized Kernel The instructions in this section apply to building a modularized kernel If you are interested in building a monolithic kernel instead see Section A 4 for an explanation of the different aspects of building and installing a monolithic kernel The following steps will guide you through building a custom kernel for the x86 architecture ote This example uses 2 4 18 7 95 as the kernel version Your kernel version might differ To determine your kernel version type the command uname r Replace 2 4 18 7 95 with your kernel version 1 The most important step is to make sure that you have a working emergency boot disk in case you make a mistake If you did not make a boot disk during the installation use the mkboot disk command to make one now The standard command is similar to mkbootdisk device dev d0 2 4 x where 2 4 x is the full version of your kernel such as 2 4 18 7 95 Once done test the boot disk to make sure that it will boot the system 2 You must have the kernel source package installed Issue the command rpm q kernel source to determine the package version if it is installed If it is not installed install the
235. nd man sftp at a shell prompt The sftp utility is only available in OpenSSH version 2 5 0p1 and higher 14 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 Linux 8 0 uses SSH Protocol 2 and RSA keys by default rip If you reinstall Red Hat Linux but 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 14 3 4 1 Generating an RSA Key Pair for Version 2 Use the following steps to generate a RSA key pair for version 2 of the SSH protocol This is the default starting with OpenSSH 2 9 122 Chapter 14 OpenSSH 1 To generate a 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
236. nd monitor volgroup optional Use to create a Logical Volume Management LVM group with the syntax volgroup name partition 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 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 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 6 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 resolvedeps Install the listed packages and automatically resolve package dependencies ignoredeps Ignore the unresolved dependencies and install the listed packages without the dependencies Packages can be specified by group or by individual package name The installation program defines several groups that contain related packages See the RedHat base comps xml file o
237. nd then restart the printer daemon If a printer appears in the main printer list with the Queue Type set to INVALID the printer config uration is missing options that are required for the printer to function properly To remove this printer from the list select it from the list and click the Delete button 26 1 Adding a Local Printer To add a local printer such as one attached to the parallel port or USB port of your computer click the New button in the main Printer Configuration Tool window The window shown in Figure 26 2 will appear Click Next to proceed Chapter 26 Printer Configuration 199 Add A New Print Queue On the following screens you will be asked to provide information for adding a new print queue Nothing will be done to your settings until you hit Apply on the last screen ncel Back Figure 26 2 Adding a Printer You will then see the screen shown in Figure 26 3 Enter a unique name for the printer in the Queue Name text field This can be any descriptive name for your printer The printer name cannot contain spaces and must begin with a letter a through z or A through Z The valid characters are a through z A through Z 0 through 9 and _ Select Local Printer from the Queue Type menu and click Next Set the Print Queue Name and Type Enter the Queue s name and select the Queue s Type Valid names can contain the characters a z A Z 0 9 and _ They must
238. nding it to them all You can however locate different keyservers One place to begin your search for keyservers and more information is Keyserver Net available at http www keyserver net You can send your public key from either the shell prompt or from a browser of course you must be online to send or receive keys from a keyserver From the shell prompt type the following gpg keyserver search keyserver net send key you yourisp net From your browser go to Keyserver Net http www keyserver net and select the option to add your own PGP public key Your next task is to copy and paste your public key into the appropriate area on the Web page If you need instructions on how to do that use the following Open your exported public key file such as mykey asc which was created in Section B 5 with a pager for example use the less mykey asc command Using your mouse copy the file by highlighting all the lines from the BEGIN PGP to END PGP notations see Figure B 1 266 Appendix B Getting Started with Gnu Privacy Guard Paste the contents of the file mykey asc into the appropriate area of the page on Keyserver Net by middle clicking with your mouse or left and right clicking if you re using a two button mouse Then select the Submit button on the keyserver page If you make a mistake press the Reset button on the page to clear your pasted key File Edit View Terminal Go Help Version GnuPG v1 0
239. ndow System Boot Loader Options General Video Card Monitor Partition Information Color Depth ER Resolution 8 640x480 v Network Configuration Authentication Firal Configuration Default Desktop GNOME KDE Package Selection Start the X Window System on boot Pre Installation Script Post installation Script Figure 7 11 X Configuration General If you are installing both the GNOME and KDE desktops you need to choose which desktop you want to be the default If you are just installing one desktop be sure to choose it Once the system is installed users can choose which desktop they want to be their default For more information about GNOME and KDE refer to the Official Red Hat Linux Installation Guide and the Official Red Hat Linux Getting Started Guide 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 7 8 2 Video Card Probe for video card is selected by default Accept this default if you want the installation program to probe for the video card during installation Probing works for most modern video cards If you select this option and the installation program can not successfully probe the video card the installation program will stop at the video card con
240. ne Me 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 IN NS ns2 example com 1 IN PTR one example com 2 IN PTR two example com After configuring the Reverse Master Zone click OK to return to the main window as shown in Figure 20 1 From the pulldown menu choose File gt Apply to write the etc named conf configuration Chapter 20 BIND Configuration 173 file write all the individual zone files in the var named directory and have the daemon reload the configuration files 20 3 Adding a Slave Zone To add a slave zone also known as a secondary master click the Add button and select Slave Zone Enter the domain name for the slave zone in the Domain name text area A new window will appear as shown in Figure 20 4 with the following options Name The domain name that was entered in the previous window Masters List The nameserver from which the slave zone retrieves its data This value must be a valid IP address You can only enter numbers and dots in the text area File Name File name of the DNS database file in var named Name slave example com Masters List 1 2 3 4 File Name slave example com zone X Cancel ox Figure 20 4 Adding a Slave Zone The configuration shown
241. neeaeaeeaees 202 26 4 Adding a Novell NetWare NCP Printer 203 26 5 Adding a JetDirect Printer oo 205 26 6 Selecting the Print Driver and Finishing 206 26 7 Printing a Test Page eee 207 26 8 Modifying Existing Printers 26 9 Saving the Configuration File cscsssessscsssssacessessessansenssosssessssesensvasesssses 209 26 10 Command Line Configuration 00 0 cseeeecseeeeceeeeaeseseeeseeseeeseee 210 26 11 Managing Your Print Jobs rere reniei aiiai eE E E 211 26 12 Configuring the CUPS Printing System 212 26 13 Additional Resources 214 27 Automated Tasks cee 215 27 1 Cron 215 27 2 Anacron 217 27 3 Aband Batch cccveecaeevsscvveiscelvevassesdeacccdeeesaeateckdacuevasscbeedhcacaseseesececadanuasseaeeciedts 218 27 4 Additional ReSOUrCES nen itea a N E a endusuetas e i 220 28 Log Files 221 28 1 Locating Log Filesi sii rnd ae r raa R inae 221 28 2 Viewing Log Files sssicscsssieesescsscececdstasgsssiesscuevateesoseosisadsescsauasabiadedeaseaavaesasavaces 221 28 3 Examining Log Files 222 29 Upgrading the Kernel 225 29 1 The 2 4 Kernel 225 29 2 Preparing to Upgrade 225 29 3 Downloading the Upgraded Kernel 226 29 4 Performing the Upgrade ricccs swvcccceciecseseeiapseedecsd lescoatevdessessacssssccsdlcovenesetestets 227 29 5 Configuring the Boot Loader vi scc ccccesiss cisssstsssvsesecsceaiuessiseesbstaspa
242. nf man page explains how to configure the Samba configuration file smbd man page describes how the Samba daemon works usr share doc samba version number docs HTML and text help files included with the samba package 16 4 2 Useful Websites http www samba org The Samba Web page contains useful documentation information about mailing lists and a list of GUI interfaces 3 redhat Chapter 17 Dynamic Host Configuration Protocol DHCP Dynamic Host Configuration Protocol DHCP is 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 including IP address gateway and DNS servers 17 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 address 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 reboot
243. ng 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 Ethernet 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 11 9 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 Select Token Ring Adapter i Adapter IBM Olympic based PCI token ring Device trO E Resource IRQ Unknown MEM 10 IOL 102 DMAO DMA1 l X Cancel Back i Forward Figure 11 9 Token Ring Settings 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 Ethernet Device page After configuring the token ring device it appears in the device list as shown in Figure 11 10 Chapter 11 Network Configuration
244. ng the l partitioning tool ice Matpa omat S9 stan en Eoen e werent ope romai St out ew lyou used fdisk to partition you must 7 LVM Volume Groups define mount points for your partitions F Vots sis Use the Edit button once you have selected a partition to define its mount dias Came i To y poih T Hard Drives Y idevihda you are manually partitioning your system you will see your current hard vaas monk aes uh Bae drive s and partitions displayed below idevinda Volume LVMPV v 19301112482 Use the partitioning tool to add edit or J idevhdb delete partitions fo t i ee devindo1 swap 4 w a as Note you must create a root partition devindb2 Volme00 LvMPV V 17477 255 2482 before you can proceed with this installation If you do not create a root lation program will not w 7 Hide RAID device LVM Volume Group members Figure 10 4 Logical Volumes Created 86 Chapter 10 LVM Configuration Network Related Configuration 3 redhat Chapter 11 Network Configuration To communicate with other computers computers need a network connection This is 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 modem xDSL e token ring CIPE e wireless device
245. nge them before continuing the installation If you prefer this type of installation check the Perform installation in interactive mode button 7 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 OFP X Configuration O HTTP Package Selection Hard Drive Pre Installation Script Post Installation Script Figure 7 2 Installation Method The Installation Method screen allows you to choose whether you want to perform a full installation or an upgrade If you choose upgrade the Partition Information and Package Selection options will be disabled They are not supported for kickstart upgrades Chapter 7 Kickstart Configurator 61 Also choose the type of kickstart installation to perform from this screen You can choose from the following options CD ROM Choose this option if you wish to install Red Hat Linux from the Red Hat Linux CD ROMs NES Choose this option if you wish to install Red Hat Linux from an NFS shared directory Two text entry boxes for the NFS server and NFS directory will appear Enter the fully qualified domain name or IP address of the NFS server For the NFS directory enter the name of the NFS directory that contains the RedHat directory of the instal
246. nload them from a Red Hat FTP mirror site A list of mirror sites is available at http www redhat com download mirror html Use Red Hat Network You can use Red Hat Network to download the kernel RPM packages and then manually upgrade to the latest kernel Or if you have elected to let the Red Hat Update Agent upgrade packages for you Red Hat Network can download the latest kernel upgrade the kernel on your system create an initial RAM disk if needed and configure the boot loader to boot the new kernel All you have to do is reboot into the new kernel For more information refer to the Red Hat Network User Reference Guide available at http www redhat com docs manuals RHNetwork If there is an updated kernel for the version of Red Hat Linux you are running download the appro priate packages using one of these methods If you used Red Hat Network to upgrade your kernel automatically you are finished just reboot your system to use the new kernel If you just down loaded the RPM packages from the Red Hat Linux errata page or from Red Hat Network proceed to Section 29 4 29 4 Performing the Upgrade Now that you have the necessary kernel RPM packages you can upgrade your existing kernel At a shell prompt as root change to the directory that contains the kernel RPM packages and follow these steps lt n It is strongly recommended that you keep the old kernel in case you have problems with the new kernel Use the i argument
247. nt for rlogin for remote login and telnet for communicating with another host via the TELNET protocol For more information about OpenSSH see Chapter 14 and the OpenSSH website at http www openssh com openssl 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 stunne1 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 19 1 displays the location of the secure server packages and additional security related packages within the package groups provided by Red Hat Linux This table also tells you whether each package is optional or not for the installation of a secure Web server Chapter 19 Apache HTTP Secure Server Configuration 159 yes yes yes Applications intemet yes openssh askpass gnome Applications Internet yes yes yes yes yes Table 19 1 Security Packages 19 3 An Overview of Certificates and Security Your secure Web server provides security using a combination of the Secure Sockets Layer SSL protocol and in most cas
248. nux system Examples Introduction ix 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 filesystems Install the webalizer RPM if you want to use a Web server log file analysis program application This style should indicate to you that the program named 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 will display 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 will exit 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 will be shown in this style When you see text shown in this style it 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 When you see a word in this style it
249. o 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 216 Chapter 27 Automated Tasks month any integer from to 12 or the short name of the month such as jan feb and so on dayofweek any integer from 0 to 7 where 0 or 7 represents Sunday or the short name of the week such as sun mon and so on command the command to execute The command can either be a command such as 1s proc gt gt tmp proc or the command to execute a custom script that you wrote 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
250. o proceed with this step choose Continue You can also choose to mount your filesystem 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 will attempt to mount your filesystem under the directory mnt sysimage If it fails to mount a partition it will notify you If you select Read Only it will attempt to mount your filesystem under the directory mnt sysimage but in read only mode If you select Skip your filesystem will not be mounted Choose Skip if you think your filesystem is corrupted Once you have your system in rescue mode a prompt appears on VC virtual console 1 and VC 2 use the Ctrl Alt F1 key combination to access VC 1 and Ctrl AIt F2 to access VC 2 sh 2 05a If you selected Continue to mount your partitions automatically and they were mounted successfully you are in single user mode To mount a Linux partition manually inside rescue mode create a directory such as foo and type 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 1 To create an installation
251. odules should be used in the initrd image This is not necessarily the same as the version number of the currently running kernel A 3 Configuring the Boot Loader Making sure the boot loader configuration file has been correctly modified is a crucial step If the file is modified incorrectly you may not be able to boot your system If this happens boot your system with the boot diskette you created earlier and try configuring the boot loader again If your boot diskette does not work refer to Chapter 8 for more information about rescue mode In order to provide a redundant boot source to protect from a possible error in a new kernel you should keep the original kernel available During the installation of Red Hat Linux 8 0 you had the option to choose either GRUB or LILO as your boot loader Refer to the appropriate section that follows A 3 1 GRUB If you selected GRUB as your boot loader the new kernel pkg script should have modified boot grub grub conf to include a section for the new kernel The default GRUB configuration file looks similar to the following NOTICE You have a boot partition This means that all kernel paths are relative to boot default 0 timeout 30 splashimage hd0 0 grub splash xpm gz title Red Hat Linux 2 4 18 7 95 root hd0 0 kernel vmlinuz 2 4 18 7 95 ro root dev hda3 258 Appendix A Building a Custom Kernel initrd initrd 2 4 18 7 95 img If you created a separate boot partition
252. of etc pam d halt otherwise it will do precisely what is specified in etc pam d foo and then run 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 182 Chapter 22 Console Access 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 auth sufficient lib security pam_timestamp so session optional lib security pam_timestamp so 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 desktop environment After the authentication expires the default is five minutes the icon disappears The u
253. ol redhat config network If you select Static IP you must provide additional networking information in the table below the network types Chapter 7 Kickstart Configurator 7 6 Authentication File Help Basic Configuration Installation Method Boot Loader Options Partition Information Network Configuration Firewall Configuration X Configuration Package Selection Pre nstallation Script Post Installation Script Authentication Configuration Authentication Use Shadow Passwords Use MDS NIS LDAP Kerberos 5 Hesiod SMB Name Switch Cache NIS Authentication C Enable NIS Figure 7 9 Authentication 67 In the 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 allows you to configure the following methods of authen tication NIS LDAP Kerberos 5 Hesiod SMB Name Switch Cache They are not enabled by default To enable one or more of these methods click the appropriate tab click the checkbutton next to Enable and enter the appropriate information for the authentication method 68 Chapter 7 Kickstart Configurator 7 7 Firewall Configuration File Help Basic Configuration Firewall Configuration Installation Method Select the default firewall level Boot Loader
254. ollowing command replace lt rpm file gt with filename of the RPM package rpm K lt rpm file gt If all goes well you will see the message md5 gpg OK That means that the signature of the package has been verified and that it is not corrupt rip For more information about GnuPG see Appendix B 31 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 If you want 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 18 Chapter 31 Package Management with RPM 243 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 rpm Vf usr bin paste and the appropriate package will be verified Do
255. olume 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 28 Logical Volume Group 9 1 GB x 3 75 MB Logical Volume Logical Volume fhome l 20 GB 2 GB 5GB Free Space Figure 4 2 Logical Volumes Chapter 4 Logical Volume Manager LVM 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 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 kernel for Red Hat Linux 8 0 is compiled with LVM support To learn how to configure LVM during the Red Hat Linux installation process refer to Chapter 10 redhat Chapter 5 Managing Disk Storage After you have installed your Red Hat Linux system you may want to view the existing partition table change the size of the partitions remove partitions or add partitions from free space or additional hard drives The utility parted allows you to perform these tasks This chapter discusses how to use parted to perform command file system tasks Alternatively you can use fdisk to perform most of these tasks excluding resizing partitions For
256. on sudo pam_unix 4650 authentication failure logname uid 0 euid 0 tty pts 2 ruser Aug 16 15 52 50 falcon sudof4650 pam_krbS authentication succeeds for tfox Aug 16 15 53 03 falcon userhelper pam_timestamp timestamp file var run sudo tfox unknown root is too old Aug 16 15 54 25 falcon userhelper pam_timestamp timestamp file var run sudotfox unknown root is only 81 Aug 16 15 56 50 falcon userhelper pam_timestamp timestamp file var run sudo tfox unknown root is only 14 Aug 16 15 59 07 falcon login pam_unix 962 check pass user unknown Aug 16 15 59 07 falcon login pam_unix 962 authentication failure logname LOGIN uid 0 euid 0 tty tty2 rus Aug 16 15 59 07 falcon login 962 pam_krbS unable to determine uid gid for user Aug 16 15 59 07 falcon login 962 pam_krbS authentication fails for test Aug 16 15 59 09 falcon login 962 FAILED LOGIN 1 FROM null FOR test Authentication failure Aug 16 15 59 11 falcon modprobe modprobe Cant locate module char major 10 134 p Ly GI o Filter for R Fiter Reset Figure 28 1 Log Viewer Chapter 28 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 pull down menu The window shown in Figure 28 2 will appear In the Log Files tab click the up and down arrows beside the refresh rate to change it Click Close to
257. only want the DHCP server to start on one of the interface you can 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 if you have a firewall machine with two network cards One network card can be config ured 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 etc sysconfig dhcpd include e 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 you accept the default of port 67 the server listens on port 67 for requests and responses to the client on port 68 If you specify a port here and use the DHCP relay agent you must specify the same port on which the DHCP relay agent should listen See Section 17 2 4 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 th
258. ontains the ISO images for example dev hda1 in the Hard Drive Partition text box and enter the directory that contains the ISO images in the Hard Drive Directory text box 62 Chapter 7 Kickstart Configurator 7 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 Upgrade existing boot loac Partition Information Network Configuration Use GRUB for the boot loader Authentication Use LILO for the boot loader Firewall Configuration GRUB Options X Configuration Use GRUB password Package Selection C Encrypt GRUB password Pre Installation Script Post Installation Script Install boot loader on Master Boot Record MBR CO Install boot loader on first sector of the boot partition Kernel parameters Figure 7 3 Boot Loader Options You have the option of installing GRUB or LILO as the boot loader If you do not want 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 disk 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 pl
259. ool to run as a text based application by using the com mand redhat config printer tui from a shell prompt To add a printer using the command line version refer to Section 26 10 EERDE Do not edit the etc printcap file Each time the printer daemon 1pa is started or restarted a new etc printcap file is dynamically created If you want to add a printer without using Printer Configuration Tool edit the etc printcap local file The entries in etc printcap local are not displayed in the Printer Configuration Tool but are read by the printer daemon If you upgrade your system from a previous version of Red Hat Linux your existing configuration file is converted to the new format used by this application Each time a new configuration file is generated the old file is saved as etc printcap old File Test Help Sak 2 New Edit Delete Default Apply Queue Aias List Queue Type Details y test LOCAL dev p0 test2 LPD Ip servername example com test3 SMB machinename example com share test4 NCP queuve servername example com Figure 26 1 Printer Configuration Tool Five types of print queues can be configured Local Printer a printer attached directly to your computer through a parallel or USB port In the main printer list as shown in Figure 26 1 the Queue Type for a local printer is set to LOCAL 198 Chapter 26 Printer Configuration Unix Printer Ipd Spool a printer attached
260. 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 server settings under the Server tab Configure the connections settings under the Performance Tuning tab Copy all necessary files to the DocumentRoot and cgi bin directories and save your settings in the HTTP Configuration Tool 18 1 Basic Settings Use the Main tab to configure the basic server settings 144 Chapter 18 Apache HTTP Server Configuration 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 X Cancel Ko Help Figure 18 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 directive sets the hostname of the
261. or a SCSI controller you need an initial RAM disk The purpose of the initial RAM disk is to allow 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 The initial RAM disk is created by using the mkinitrd command However the Red Hat kernel RPM package performs this step for you To verify that it was created use the command 1s 1 boot You should see the file initrd 2 4 18 7 95 img the version should match the version of the kernel you just installed Now that you have installed the new kernel you need to configure the boot loader to boot the new kernel Refer to Section 29 5 for details 29 5 Configuring the Boot Loader The kernel RPM package configures the GRUB or LILO boot loader to boot the newly installed kernel if either boot loader is installed 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 you will not be able to boot your system If this happens boot your system with the boot diskette you created earlier and try configuring the boot loader again 29 5 1 GRUB If you selected GRUB as your boot loader confirm that the file boot grub grub conf contains a title section with the same version as the kernel package you just installed if y
262. or all of the following packages depending on what type of installation you performed your version numbers and packages may differ kernel 2 4 18 7 95 kernel debug 2 4 18 7 95 kernel source 2 4 18 7 95 kernel doc 2 4 18 7 95 kernel pcemcia cs 3 1 27 12 kernel smp 2 4 18 7 95 From the output you can determine which packages you need to download for the kernel upgrade For a single processor system the only required package is the kernel package If you have a computer with more than one processor you need the kernel smp package that con tains support for multiple processors It is recommended that you also install the kernel package in case the multi processor kernel does not work properly for your system If you have a computer with more than four gigabytes of memory you need the kernel bigmem package Again it is recommended that you also install the kernel package for debugging purposes The kernel bigmem package is only built for the 1686 architecture If you are upgrading the kernel on a laptop or are using PCMCIA the kernel pcmcia cs package is also required You do not need the kernel source package unless you plan to recompile the kernel yourself or plan to perform kernel development The kernel doc package contains kernel development docu mentation and is not required The kernel util package includes utilities that can be used to control the kernel or the system s hardware and is not required Red Hat builds kernels th
263. or the Directory Page Search List and Error Pages will work for most servers If you are unsure of these settings do not modify them Site Configuration Directory Page Search List Logging Me Ai 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 Edit Bad Request default t Authorization Required default Forbidden default Not Found default Method Not Allowed default Lv Error Code 400 Bad Request Default Error Page Footer Show footer with email address Help Pox X Cancel Figure 18 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 your_domain this_directory they are going to get either the DirectoryIndex page if it exists or a server generated directory list The server will try to find one of the files listed in the Direct oryIndex directive and will return the first one it finds If it does not find any of these files and if Options Indexes is set for that directory the ser
264. orm Feed FF 209 edit driver 209 edit existing printer 208 exporting settings 210 importing settings 210 local printer 198 LPRng 197 managing print jobs 212 modifying existing printers 208 Novell NetWare NCP printer 203 overriding a printer 208 printing from the command line 212 remote UNIX printer 200 rename existing printer 208 Samba SMB printer 202 save configuration to file 210 strict RFC1179 compliance 201 test page 207 text based application 197 viewing print spool 212 Printer Configuration Tool See printer configuration printtool See printer configuration processes 189 ps 189 R RAID 23 configuring software RAID 79 explanation of 23 Hardware RAID 23 level 0 24 level 1 24 level 4 24 level 5 24 levels 24 reasons to use 23 Software RAID 23 RAM 191 rep 120 Red Hat Network 251 redhat config apache See HTTP Configuration Tool redhat config date See Time and Date Properties Tool redhat config kickstart See Kickstart Configurator redhat config network 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 Properties Tool redhat config users See user configuration and group configuration redhat logviewer See Log Viewer redhat switch printer See Printer Syst
265. ot 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 for 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 adding modifying or deleting shares the nfs service must be restarted for the changes to take effect To apply the changes to the configuration file and resta
266. ou installed the kernel smp and or kernel bigmen you will have a section for it has well NOTICE You have a boot partition This means that all kernel paths are relative to boot default 0 timeout 30 splashimage hd0 0 grub splash xpm gz title Red Hat Linux 2 4 18 7 95 root hd0 0 kernel vmlinuz 2 4 18 7 95 ro root dev hda3 initrd initrd 2 4 18 7 95 img If you created a separate boot partition the paths to the kernel and initrd image are relative to the boot partition 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 second title section set default to 1 You can begin testing your new kernel by rebooting your computer and watching the messages to ensure your hardware is detected properly Chapter 29 Upgrading the Kernel 229 29 5 2 LILO If you selected LILO as your boot loader confirm that the file etc 1lilo conf contains an image section with the same version as the kernel package you just installed boot dev hda map boot map install boot boot b prompt timeout 50 message boot message linear default linux image boot vmlinuz 2 4 18 7 95 label linux initrd initrd 2 4 18 7 95 img read only root dev hda5 The kernel RPM package activates the changes by running the command sbin lilo To configure LILO to boo
267. ou used when adding the printer If you change the print driver click OK to return to the main window Click Apply to save the change and restart the printer daemon 26 8 4 Driver Options The Driver Options tab displays advanced printer options Options vary for each print driver Com mon options include Send Form Feed FF should be selected if the last page of your print job is not ejected from the printer for example the form feed light flashes If this does not work try selecting Send End of Transmission EOT instead Some printers require both Send Form Feed FF and Send End of Transmission EOT to eject the last page Send End of Transmission EOT if sending a form feed does not work Refer to Send FF above Assume Unknown Data is Text should be selected if your print driver does not recognize some of the data sent to it Only select it if you are having problems printing If this option is selected the print driver will assume that any data that it can not recognize is text and try to print it as text If you select this option and Convert Text to Postscript the print driver will assume the unknown data is text and then convert it to PostScript Prerender Postscript should be selected if you are printing characters beyond the basic ASCII set but they are not printing correctly such as Japanese characters This option will prerender non standard PostScript fonts so that they are printed correctly If your printer
268. ou want the installation program to probe for the monitor during installation Probing works for most modern monitors If you select this option and the installation program can not 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 specifying a 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 Chapter 7 Kickstart Configurator Eile Help Installation Method Boot Loader Options Partition Information Network Configuration Authentication Firewall Configuration X Configuration Package Selection Pre Installation Script Post Installation Script Basic Configuration X Configuration lt Configure the X Window System General Video Card Monitor Probe for monitor ViewSonic OptiQuest V55 ViewSonic OptiQuest V641 ViewSonic OptiQuest V655 2 ViewSonic OptiQuest V655 3 ViewSonic OptiQuest V655 ViewSonic OptiQuest V73 ViewSonic OptiQuest V75 ViewSonic OptiQuest V773 2 ViewSonic OptiQuest V773 ViewSonic OptiQuest V775 2 ViewSonic OptiQuest V775 ViewSonic Opt
269. ow 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 SSHELL 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 2 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 14 4 Additional Resources The OpenSSH and OpenSSL projects are in constant development so the most up to date information for them will be found on their websites The man pages for OpenSSH and OpenSSL tools are also good sources of detailed information 14 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 14 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 E redhat Chapter 15 Network File System NFS Network File System NFS is a way to share files between machines on a network
270. owever we hope you will gain enough understanding about GnuPG to begin using cryptography in your own correspondence For more information about GnuPG includ ing an online users guide visit http www gnupg org If you want to learn more about GnuPG PGP and encryption technology see Section B 8 262 Appendix B Getting Started with Gnu Privacy Guard B 2 Warning Messages When executing GnuPG commands you will probably see the message gpg Warning using insecure memory This warning is because non root users can not lock memory pages If users could lock memory pages they could perform out of memory denial of service attacks thus it is a possible security problem For details refer to http www gnupg org faq html q6 1 If you upgraded from a previous version of GnuPG you might see the message gpg WARNING honor http proxy is a deprecated option gpg please use keyserver options honor http proxy instead This warning is because your gnupg options file contains the line honor http proxy Version 1 0 7 prefers a different syntax Change the line to the following keyserver options honor http proxy B 3 Generating a Keypair To begin using GnuPG you must first generate a new keypair a public key and a private key To generate a keypair at a shell prompt type the following command gpg gen key Since you work with your user account most frequently you should perform this action while logged in to
271. p 27 83 Ww Windows file and print sharing 131 Windows 2000 connecting to shares using Samba 132 Windows NT 4 0 connecting to shares using Samba 132 X xDSL connection See network configuration xinetd 114 E redhat The Official Red Hat Linux 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 Colophon Marianne Pecci lt goddess ipass net gt created the admonition graphics note tip important cau tion and warning They may be redistributed with written permission from Marianne Pecci and Red Hat Inc The Red Hat Linux Product Documentation Team consists of the following people Sandra A Moore Primary Writer Maintainer of the Official Red Hat Linux x86 Installation Guide Contributing Writer to the Official Red Hat Linux Getting Started Guide Tammy Fox Primary Writer Maintainer of the Official Red Hat Linux Customization Guide Con tributing Writer to the Official Red Hat Linux Getting Started Guide Writer Maintainer of custom DocBook stylesheets and scripts Edward C Bailey Contributing Writer to the Official Red Hat Linux x86 Installation Guide Johnray Fuller Primary Writer Maintainer of the Official Red Hat Linux Reference Guide Co writer Co maintainer of the Official Red Hat Linux Security Guide John Ha Primary Writer Maintainer to the Official Red Hat Linux Getting Started Guide
272. ports 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 O array is equal to the total capacity of the member disks in a Hardware RAID or the total capacity of member partitions in a Software 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 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
273. post 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 Chapter 6 Kickstart Installations 55 rote 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 filesystem that was just in stalled Spost nochroot cp etc resolv conf mnt sysimage etc resolv conf interpreter usr bin python Allows you to specify a different scripting language such as Python Replace usr bin python with the scripting language of your choice 6 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 6 8 Making the Kickstart File Available A kickstart file must be placed in one of two locations Ona boot diskette Ona network Normally a kicksta
274. pport for a wide range of printers 26 12 1 Switching Print Systems To use the CUPS printing system instead of LPRng run the Printer System Switcher application Start it by selecting to the Main Menu Button on the Panel gt Extras gt System Settings gt Printer System Switcher or type the command redhat switch printer at a shell prompt for example in an XTerm or GNOME terminal The program automatically detects if the X Window System is running If it is running the program starts in graphical mode as shown in Figure 26 15 If X is not detected it starts in text mode To force it to run in text mode use the command redhat switch printer nox Chapter 26 Printer Configuration 213 The redhat switch printer is a tool which enables users to G easily switch between various Printing System LPRng CUPS s gt that they have installed Please choose your Printing System Available Printing System LPRng CUPS Figure 26 15 Printer System Switcher If you selected CUPS you must make sure the 1pd service is stopped and the cups service is started sbin service lpd stop sbin service cups start If you selected LPRng you must make sure the cups service is stopped and the 1pd service is started sbin service cups stop sbin service lpd start Also use chkconfig ntsysv or Services Configuration Tool to configure your sytsem to start the cups Service automatically and disable the 1pd service Refer to Cha
275. printcap file and overwrite your existing etc printcap file with the saved file your printer configuration will not be restored Each time the printer daemon is restarted it creates anew etc printcap file from the special Printer Configuration Tool configuration file If you have configured a backup system for your configuration files you should use the following method to save your printer configuration If you added any custom settings in the etc printcap local file you should save it as part of your backup system also 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 you save this file you can restore your printer settings This is useful if your printer configuration is deleted you reinstall Red Hat Linux and do not have your printer configuration file anymore or you want to use the same printer configuration on multiple systems 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
276. ptables service 111 security levels high 105 medium 106 no firewall 106 sendmail 175 services controlling access to 113 Services Configuration Tool 115 sftp See OpenSSH shutdown disablingCtrlAltDel 179 SMB protocol 131 smb conf 131 Software RAID See RAID ssh See OpenSSH ssh add 124 ssh agent 123 with GNOME 123 striping RAID fundamentals 23 swap space 19 adding 19 explanation of 19 moving 21 recommended size 19 removing 20 syslogd 221 system information file systems 192 dev shm 192 monitoring 193 gathering 189 hardware 194 memory usage 191 processes 189 currently running 189 T TCP wrappers 114 telinit 114 telnet 119 time configuration 183 synchronize with NTP server 184 time zone configuration 184 timetool See Time and Date Properties Tool token ring connection See network configuration top 189 tune2fs converting to ext3 with 16 reverting to ext2 with 16 U user configuration adding users 185 adding users to groups 187 changing full name 187 changing home directory 187 changing login shell 187 changing password 187 filtering list of users 185 locking user accounts 187 modify groups for a user 186 modifying users 186 password expiration 187 setting user account expiration 187 viewing list of users 185 User Manager See user configuration users See user configuration Vv VeriSign using existing certificate 160 volume grou
277. pter 13 for details 26 12 2 CUPS Configuration Interface After starting the cups daemon open a Web browser and connect to the URL http localhost 631 as shown in Figure 26 16 214 Chapter 26 Printer Configuration File Edit View Tab Settings Go Bookmarks Tools Help lt Back gt 7 Q at stop 100 5 amp nttpstocahostear gt g Jay Administration Classes Help Jobs Printers Software Do Administration Tasks Manage Printer Classes On Line Help Manage Jobs Manage Printers Download the Current CUPS Software The Common UNIX Printing System CUPS and the CUPS logo are the trademark property of Easy Software Products CUPS is copyright 1997 2002 by Easy Software Products All Rights Reserved Figure 26 16 CUPS Configuration Tool To add a printer click Manage Printers and then click the Add Printer button For more informa tion click the Help button 26 13 Additional Resources To learn more about printing on Red Hat Linux refer to the following resources 26 13 1 Installed Documentation man printcap The manual page for the etc printcap printer configuration file map lpr The manual page for the 1pr command that allows you to print files from the command line man lpd The manual page for the LPRng printer daemon e man lprm The manual page on the command line utility to remove print jobs from the LPRng spool queue man mpage The manual
278. 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 a 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 allovw file which you will create in the next step 2 Create a file named shutdown allowin etc The shutdown allow 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 shutdown the system from the console using Ctrl Alt Del When that key combination is used the shut down 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 will continue if not an error message will be written to the system console instead For more information on shut down allow see the shut down man page 180 Chapter 22 Console Access 22 2 Disabling Console Program Access In order to disable access b
279. r 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 capacity 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
280. r 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 rote 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 Python Replace usr bin python with the scripting language of your choice 6 6 1 Example Here is an example pre section F Spre bin sh hds mymedia for file in proc ide h 54 Chapter 6 Kickstart Installations do mymedia cat file media if mymedia disk then hds Shds basename file fi done set hds numhd echo drivel echo hds cut d f1 drive2 echo Shds cut d f2 Write out partition scheme based on whether there are 1 or 2 hard drives if Snumhd 2 then 2 drives 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 echo part swap recommended ondisk drivel gt gt tmp part include echo part home fstype ext3 size 1 grow
281. ration Network Administration Tool See network configuration network configuration activating devices 101 CIPE connection 97 activating 99 device aliases 103 Ethernet connection 90 activating 91 ISDN connection 91 activating 92 logical network devices 101 managing etc hosts 99 managing DNS Settings 100 managing hosts 99 modem connection 93 activating 94 overview 89 profiles 101 token ring connection 96 activating 97 wireless connection 98 xDSL connection 94 activating 95 Network File System See NFS Network Time Protocol See NTP NFS etc fstab 125 additional resources 130 autofs See autofs command line configuration 128 configuration 125 exporting 126 hostname formats 129 mounting 125 starting the server 129 status of the server 129 stopping the server 129 NFS Server Configuration Tool 126 NTP configuring 184 ntp conf 184 ntpd 184 step tickers 184 ntpd 184 ntsysv 116 273 0 O Reilly amp Associates Inc 130 156 268 OpenSSH 119 additional resources 124 client 120 scp 120 sftp 121 ssh 120 DSA keys generating 122 generating key pairs 121 RSA keys generating 121 RSA Version 1 keys generating 122 server 119 etc ssh sshd_config 119 starting and stopping 119 ssh add 124 ssh agent 123 with GNOME 123 ssh keygen DSA 122 RSA 121 RSA Version 1 122 OpenSSL additional resources 124 P Package Management Tool 247 installing pac
282. rator 73 7 11 Post Installation Script File Help Basic Configuration Post Installation Script Boot Loader Options Warning An error in this script might cause your kickstart installation to fail Do not include the post command at the beginning Installation Method trad beginning Partition Information Network Configuration Authentication Firewall Configuration Type your post script below X Configuration tside of the chroot e an interpreter Package Selection Pre installation Script Figure 7 16 Post Installation Script You can also add commands to execute on the system after the installation is completed If you have properly configured the network in the kickstart file the network is enabled If you would like to include a post installation script type it in the text area Efon 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 rip More examples can be found at Section 6 7 1 7 11 1 Chroot Environment If you want your post installation script to run outside of the chroot environment click the checkbutton 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 74 Chapter 7 Kickstart Configurator Drip If yo
283. re Add v Active ethO tho He Edit copy Delete Activate 8 Heip Apply X Close Figure 11 13 Wireless Device Be sure to click Apply 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 as seen by its Inactive status To activate the device select it from the device list and click the Activate button 11 9 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 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 click Add in the Hosts tab provide the requested information and click OK Click Apply to write the entry to the file warning Do not remove the localhos
284. rectory The Bind Configuration Tool also includes basic syntax checking when values are entered For example if a valid entry is an IP address you are only allowed to type numbers and the dot character into the text area The Bind Configuration Tool allows you to add a forward master zone a reverse master zone and a slave zone After adding the zones you can edit or delete them from the main window as shown in Figure 20 1 After adding editing or deleting a zone you must choose File gt Apply to write the etc named conf configuration file and all the individual zone files in the var named directory Applying your changes will also cause the named service reload the configuration files You can also choose File gt Quit and click Save and quit 170 Chapter 20 BIND Configuration 20 1 Adding a Forward Master Zone To add a forward master zone also known as a primary master click the Add 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 20 2 will appear with the 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
285. rences between RAID 0 1 and 5 Software RAID can be configured during the graphical installation of Red Hat Linux or during a kickstart installation You can use fdisk or Disk Druid to create your RAID configuration but these instructions will focus mainly on using Disk Druid to complete this task Before you can create a RAID device you must first create RAID partitions using the following step by step instructions Qrip If you are using fdisk to create a RAID partition remember that instead of creating a partition as type 83 which is Linux native you must create the partition as type fa Linux RAID Also for best performance partitions within a given RAID array should span identical cylinders on drives 1 On the Disk Partitioning Setup screen select Manually partition with Disk Druid 2 In Disk Druid choose New to create a new partition 3 You will not be able to enter a mount point you will be able to do that once you have created your RAID device 4 Choose software RAID from the File System Type pull down menu as shown in Figure 9 1 Add Partition Mount Point Not Applicable File System Type I software RAID hda 19469 MB_ Maxtor 520493 Allowable Drives hdb 19469MB Maxtor 52049H3 Size MB 3000 Additional Size Options Fixed size O Fill all space up to MB Fill to maximum allowable size Force to be a primary partition C Check for bad blocks X cancel Po
286. rent configuration 208 Chapter 26 Printer Configuration 26 8 Modifying Existing Printers To delete an existing printer select the printer and click the Delete button on the toolbar The printer will be 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 first column of the printer list beside the default printer If you want to modify an imported printer s settings you cannot modify its settings directly You must override the printer You can only override an imported printer that has been imported using the alchemist libraries Imported printers have the symbol beside them in the first column of the printer list To override the printer select the printer and choose File gt Override Queue from the pulldown menu After overriding a printer the original imported printer will have the symbol beside it in the first column of the printer list After adding your printer s you can edit settings by selecting the printer from the printer list and clicking the Edit button The tabbed window shown in Figure 26 14 will appear The window contains the current values for the printer that you selected to edit Make any changes and click OK Click Apply in the main Printer Configuration Tool window to save the changes and restart the printer
287. respondents or to a keyserver you must export the key To export your key so you can display it on a Web page or paste it in email type the following command gpg armor export lt you yourisp net gt gt mykey asc You will not see any output because not only did you export your public key you redirected the output to a file called for example mykey asc Without the addition of gt mykey asc the key would have been displayed as the standard output on the monitor screen Now the file mykey asc can be inserted into email or exported to a keyserver To see the key type less mykey asc to open the file in a pager type q to quit the pager It should look like the following Version GnuPG v1 0 1 GNU Linux Comment For info see http www gnupg org mQGiBDkHP 3URBACkWGsYh4 3pkXU 9wj X1G67K8 DSr185r7dNtHNfLL ewill0k2 Appendix B Getting Started with Gnu Privacy Guard 265 q8saWJn260ZP sDVqdUJMOdHf J6kQOTAt INzObgcVrxLYNfgeBsvkHF POtnYcZRgL tZ6syBBWs8JB4xt5V09iJSGAMPUQE8Jpdn2aRXPApdoDw17 9LM8Rq6r gwCg5ZZa pGN1kgFu24WM5wC1zg4QTbMD 3MJCSxfL99Ek 5HXcB3yhj o0LmIrGAVBgoWdrRd BIGJQOFhV1NSwC8YhN 4nGHWpaTxgEtnb4CI1lw1I G3DK9IO1LYMyRJinkGJ6XYfP3b cCQmgqATDF 5ugIAmdditnw7dexXqn eavaMxRXJM ROSgJJyVpbA020qKe6L6Inb5H kjcZA 9obTm4 99dDMRO CNR92 fA5prO0zriy ziLUow cqI5 9nt bEb9InY1mfMUN6 SWO JCH pIQH5lerV EookyOyq3o0cUdjeRYF d2j19xmeSyL2H3tDvnuE6vgqFU N sdvby4B21ku7S h0 6W6GPQAe pzdyX9vS Pnf 80su7W3 j 60WprOkUGF 1bCBHYWxs YWdoZXIgPHBhdWxn
288. revocation To generate a revocation certificate use the gen revoke option gpg output revoke asc gen revoke lt you yourisp net gt Note that if you omit the output revoke asc option from the above your revocation certificate will be returned to the standard output which is your monitor screen While you can copy and paste the contents of the output into a file of your choice using a text editor it is probably easier to send the output to a file in your login directory That way you can keep the certificate for use later or move it to a diskette and store it someplace safe The output will look similar to the following sec 1024D 823D25A9 2000 04 26 Your Name lt you yourisp net gt Create a revocation certificate for this key Press Y to create a revocation certificate for the listed key Next you will be asked to select the reason for revocation and provide an optional description After confirming the reason enter the passphrase you used to generate the key Once your revocation certificate has been created revoke asc it will be located in your login directory You should copy the certificate to a floppy diskette and store it in a secure place If you do not know how to copy a file to a diskette in Red Hat Linux see the Official Red Hat Linux Getting Started Guide B 5 Exporting your Public Key Before you can use public key cryptography other people must have a copy of your public key To send your key to cor
289. ring upgrades RPM handles configuration files carefully so that you never lose your customiza tions something that you will 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 rote Because RPM makes changes to your system you must be root in order to install remove or upgrade an RPM package 31 1 RPM Design Goals In order 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 Linux you don t need to reinstall on your machine as you do with operating systems based on other 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 Powerf
290. ript 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 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 27 3 3 for more information Usage of the at command can be restricted Refer to Section 27 3 5 for details 27 3 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 emai
291. rom the boot img or bootnet img image file the correct boot command would be boot linux ks floppy The linux ks floppy command also works if the ks cfg file is located on a vfat or ext2 filesys tem on a floppy diskette and you boot from the Red Hat Linux CD ROM An alternate boot command for booting off the Red Hat Linux CD ROM and having the kickstart file on a vfat or ext2 filesystem on a floppy diskette is boot linux ks hd fd0 ks cfg If you need to use a driver disk with kickstart you can still have the kickstart file on a floppy disk boot linux ks floppy dd The Red Hat Linux installation program looks for a kickstart file if the ks command line argument is passed to the kernel The command line argument can take a number of forms 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 ks http lt server gt lt path gt The installation program will look for the kickstart file on the HTTP server lt 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 kickstar
292. ron service from checked to unchecked and then click the Save Changes button the runlevel 3 configuration changes so that anacron is not started at boot time However runlevel 3 is not reinitialized so anacron is still running Select one of following options at this point 1 Stop the anacron service Stop the service by selecting it from the list and clicking the Stop the selected service button A message will be displayed stating that the service was stopped successfully 2 Re initialize the runlevel Reinitialize the runlevel by going to a shell prompt such as an XTerm or GNOME terminal 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 more than one service and want to activate the changes immediately 3 Do nothing else You do not have to stop the anacron service You can wait until the system is rebooted for the service to stop The next time the system is booted the runlevel will be initialized without the anacron service running 13 4 ntsysv The ntsysv utility provides a simple interface for activating or deactivating services You can use ntsysv to turn an xinet d managed service on or off You can also use ntsysv to start or stop a service in the etc rc d hierarchy in that case the nt sysv command without options is used to configure current runlevel If you want to configure a different runlevel use something like ntsysv lev
293. 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 configuration 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 with the command sbin service lpd restart or by starting Printer Configu ration Tool and clicking Apply 26 10 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 using the command line This method is useful if you want to add a printer from a script or in the post of a kickstart installation 26 10 1 Adding a Printer To add a printer redhat config printer tui Xadd local options Options device node The device node to use For example dev 1p0 required Chapter 26 Printer Configuration 211 make make The IEEE 1284 MANUFACTURER string or the printer manufacturer s name as in the foomatic database if the manufacturer string is not available required model model The IEEE 1284 MODEL string or the printer model in the foomatic database if the model string is not available required name name The name to
294. roperly 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 31 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 31 5 for more information on RPM 31 2 1 Finding RPM Packages Before using an RPM you must know where to find them An Internet search will return many RPM repositories but if you are looking for RPM packages built by Red Hat they can be found at the following locations The official Red Hat 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 html Red Hat Network See Chapter 33 for more details on Red Hat Network 31 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 succe
295. rt 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 56 Chapter 6 Kickstart Installations 6 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 Note that the Red Hat Linux boot diskettes are in MS DOS format so 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 and cp the file over 6 8 2 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 kick
296. rt 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 certificate request your certificate will no longer work and the CA will not be able to help you Your only option would be to request and pay for a new certificate If you are going to purchase a certificate from a CA continue to Section 19 7 If you are generating your own self signed certificate continue to Section 19 8 19 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 will 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 will display the following output and will ask you for your password unless you disabled the password 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 PEM pass phrase Type in the password that you chose when you were generating your key Your system will display some instructions and then ask for a series of responses from you Your inputs will be incorporated into
297. rt the service click the Apply button If the nfs service is not already running you will be prompted to start the service Select Yes to start the daemon The daemon must be running to export the configured directories The old configuration file will be saved as etc exports bak and the new configuration will be written to etc exports 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 modifying the file manually provided the file was modified with correct syntax 15 3 1 Command Line Configuration If you prefer editing configuration files using a text editor or if you do have 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 options are not required For example misc export speedy redhat com would allow users from speedy redhat com to mount misc export with the default read only permissions but misc export speedy redhat com rw Chapter 15 Network File System NFS 129 would allow users from speedy redhat com to mount misc export with read write privileges Refer to Section 15 3 2 for an explanation of possible hostname formats Refer to the Official Red Hat Linux Reference Guide for a list of options that can be
298. rupt If everything verified properly there will be no output If there are any discrepancies they will be 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 s file size L symbolic link T file modification time D device 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 31 3 Checking a Package s Signature If you wish to verify that a package has not been corrupted or tampered with examine only the md5sum 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 You will see the message lt rpm file gt md5 OK 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 wi
299. rypt your entire message In a clearsigned message your signature appears as a text block within the context of your letter a detached signature is sent as a separate file with your correspondence B 8 Additional Resources There is more to encryption technology than can be covered in one slim introduction to GnuPG Here are some resources where you can learn more B 8 1 Installed Documentation man gpgand info gpg Quick Reference of GnuPG commands and options B 8 2 Useful Websites http www gnupg org The GnuPG website with links to the latest GnuPG releases a compre hensive user s guide and other cryptography resources http hotwired lycos com webmonkey backend security tutorials tutoriall html Visit the Encryption Tutorial from Webmonkey to learn more about encryption and how to apply encryption techniques http www eff org pub Privacy The Electronic Frontier Foundation Privacy Security Crypto amp Surveillance Archive 268 Appendix B Getting Started with Gnu Privacy Guard B 8 3 Related Books The Official PGP User s Guide by Philip R Zimmerman MIT Press PGP Pretty Good Privacy by Simson Garfinkel O Reilly amp Associates Inc E Mail Security How to Keep Your Electronic Messages Private by Bruce Schneier John Wiley amp Sons Index Symbols dev shm 192 etc auto master 126 etc exports 128 etc fstab 16 125 etc hosts lpd 202 etc httpd conf h
300. s 1 Click the Devices tab 2 Click the Add button 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 ote The installation program usually detects supported Ethernet devices and prompts you to con figure them If you configured any Ethernet devices during the installation they will already appear 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 On the Configure Network Settings page as shown in Figure 11 1 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 Configure Network Settings i Automatically obtain IP address settings with hcp 7 HCF n Z Automatically obtain DNS information from provider O Statically set IP addresses Aanual IP Address Settings
301. s To use the Network Administration Tool you must be running the X Window System and 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 prefer modifying the configuration files directly refer to the Official Red Hat Linux Reference Guide for information on their location and contents rio Go to the Red Hat Hardware Compatibility List http hardware redhat com hcl to determine if Red Hat Linux supports your hardware device 11 1 Overview To configure a network connection with the Network Administration Tool perform the following steps 1 Add the physical hardware device to the hardware list 2 Add a network device associated with the physical hardware device 3 Configure any hosts that can not be looked up through DNS 4 Configure the hostname and DNS settings This chapter will discuss each of these steps for each type of network connection 90 Chapter 11 Network Configuration 11 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 There are different speeds to networks make sure your NIC is compatible with the network to which you want to connect To add an Ethernet connection follow these step
302. s Edit Delete Pass to CGI Scripts ladd Edit Delete Unset for CGI Scripts Ada Edit Delete 8 Help ox amp Cancel Figure 18 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 Section 18 2 3 and type MAXNUM in the Environment Variable text field and 50 in the Value to set text field Click OK The Set for CGI Scripts section configures the SetEnv 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 envi ronment variable in the resulting dialog box Click OK 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 Scripts section and enter the name of the environment variable to unset This corresponds to the Unset Env directive 18 2 4 Directories Use the Directories page to configure options for specific directories This corresponds to the lt D
303. s RAID level 5 but level 5 has more advantages For this reason level 4 is not supported 26 Chapter 3 Redundant Array of Independent Disks RAID reana Chapter 4 Logical Volume Manager LVM Beginning with Red Hat Linux 8 0 Logical Volume Manager LVM is available for hard drive allo cation 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 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 you want to have the root partition on a logical volume you will need to 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 if you want the logical volume group to span over more than one drive you must create one or more physical volumes per drive Logical Volume Group 9 1 GB x 3 75 MB 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 v
304. s can be complicated and is best tackled by experienced UNIX 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 See the Official Red Hat Linux Reference Guide for more information about iptables Alternatively if you are looking for a utility which will set general access rules for your home ma chine and or if you are new to Linux you should try the GNOME Lokkit utility GNOME Lokkit is a GUI utility which will ask you questions about how you want to use your machine Based on your answers it will then configure a simple firewall for you Refer to Chapter 12 for more information You can also use the Services Configuration Tool redhat config servicelevel It allows you to select the security level for your system similar to the Service Level screen in the Red Hat Linux installation program 13 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 Red Hat Linux uses the following runlevels 114 Chapter 13 Controlling Access to Services 0 Halt 1 Single user mode 2 Not used user definable 3 Full multi user mode 4 Not used user
305. s of a default Red Hat Linux kernel copy the the configuration file from the usr src linux 2 4 configs directory to usr src linux 2 4 config Then run the make xconfig command and only make the desired changes Be sure to save your changes to the configuration file Other available methods for kernel configuration are listed below e make config An interactive text program Components are presented in a linear format and you answer them one at a time This method does not require the X Window System and does not allow you to change your answers to previous questions make menuconfig A text mode menu driven program Components are presented in a menu of categories you select the desired components in the same manner used in the text mode Red Hat Linux installation program Toggle the tag corresponding to the item you want included built in exclude lt M gt module or lt gt module capable This method does not require the X Window System make oldconfig This is a non interactive script that will set up your configuration file to contain the default settings If you are using the default Red Hat Linux kernel it will create a configuration file for the kernel that shipped with Red Hat Linux for your architecture This is useful for setting up your kernel to known working defaults and then turning off features that you do not want ote To use kmod see Chapter 30 for details and kernel modules you must
306. s the module supports For a complete list of options refer to the modinfo man page man modinfo 30 2 Additional Resources For more information on kernel modules and their utilities refer to the following resources 30 2 1 Installed Documentation lsmod man page description and explanation of its output 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 Package Management 3 redhat Chapter 31 Package Management with RPM The RPM Package Manager RPM is an open packaging system available for anyone to use which runs on Red Hat 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 and 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 32 for details Du
307. s the following features The directory for the kernel source is usr src linux 2 4 instead of usr src linux Support for the ext3 filesystem Multi processor SMP support USB support e Preliminary support for IEEE 1394 also referred to as FireWire devices 29 2 Preparing to Upgrade Before you upgrade your kernel you must take a few precautionary steps The first step is to make sure you have a working boot diskette for your system in case a problem occurs If the boot loader is not configured properly to boot the new kernel you will not be able to boot your system unless you have a boot diskette To create a boot diskette for your system you need to determine which version of the kernel you are currently running Execute the following command uname r You must be root to create a boot diskette for your system Login as root at a shell prompt and type the following command where kernelversionis the output of the uname r command sbin mkbootdisk kernelversion 226 Chapter 29 Upgrading the Kernel rip Refer to the man page for mkboot disk for more options Reboot your machine with the boot diskette and verify that it works before continuing Hopefully you will not have to use the diskette but you should store it in a safe place just in case To determine which kernel packages you have installed execute the following command at a shell prompt rpm qa grep kernel The output will contain some
308. sages 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 if you are trying to troubleshoot a problem with the system such as trying to load a kernel driver or if you are 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 28 1 Locating Log Files Most log files are located in the var log directory Some applications such as httpd and samba have a directory within var 1log 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 28 2 Viewing Log Files Most log files are in plain text format You c
309. 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 as seen by its Inactive status To activate the device select it from the device list and click the Activate button 11 5 Establishing an xDSL Connection DSL stands for Digital Subscriber Lines There are different types of DSL such as ADSL IDSL and SDSL Network Administration Tool uses the term xDSL to mean all types of DSL connections Some DSL providers require you to configure your system 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 11 2 to configure your Ethernet card If you are required to use PPPoE follow these steps 1 Click the Devices tab 2 Click the Add button 3 Select xDSL connection from the Device Type list and click Forward 4 If your Ethernet card is already in the hardware list select the Ethernet Device from the pull down menu from the page shown in Figure 11 7 Otherwise
310. scccssssssccssssssssssscsessssssssesecssssssessesssesessesesssesessesesasesssesseseseseseesene 177 22 CONSOLE ACCESS oh ier dees E EEN 179 22 1 Disabling Shutdown Via Ctrl Alt Del o cee eee ee ceeeeseseeseeeeeaeseeeeee 179 22 2 Disabling Console Program ACCESS ccc eseseesesesescseeeeeeeeeeseeeeesaeseseeees 179 22 3 Disabling All Console Access 180 22 4 Defining the Console eee 180 22 5 Making Files Accessible From the Console 180 22 6 Enabling Console Access for Other Applications 22 7 The floppy Group 23 Time and Date Configuration 23 1 Time and Date Properties yrei ea iTe i a E REEE e 183 23 2 Time Zone Configuration 24 User and Group Configuration s sssri st Eso TE IPEE EEES ESPRAI SIETO EES EETRIS arini DAT Adding a New Useiniene nna e Ea ite E N ERE 24 2 Modifying User Properties 24 3 Adding a New Group 24 4 Modifying Group Properties 25 Gathering System Information 25 1 System Processes 25 2 Memory Usage 25 3 File Systems 25 4 Hardware 25 5 Additional RESOULCES vsvcccccccussraveseseccsssssayeaseveccssusbiotessvdceusuepvesenededcessspapersiscsctes 26 Printer CONi guration sissies gres ceeds yo it tt EK E EEA EARRA 26 1 Adding a Local Printer 26 2 Adding a Remote UNIX Printer oo cece eeseesceesesceeeeceeseeeseseeeeesaeaeseeeee 200 26 3 Adding a Samba SMB Printer cceesceesseeeeeeeeceeeeeeeeseeeceeeeeeecnenee
311. seedeuesscaedbess 228 30 Kernel Modules 231 30 1 Kernel Module Utilities maese an ATE E EE o 231 30 2 Additional Resources 232 V Package Management 233 31 Package Management with RPM sessssssssesssesssssrresresrsrtsrsstsesstsrsntsrssrntntsrenesnrnesstseest 235 311 REM Desist Goals nunnan ernie nii Ea E R 235 312 Use RPM sii creat ay aCe pE RERE eueededeaiesseteetesederitienneedices 236 241 242 244 247 31 3 Checking a Package s Signature 31 4 Impressing Your Friends with RPM 31 5 Additional Resources 32 Package Management Tool 32 1 Installing Packages 247 32 2 Removing Packages vrase irritera iara E EEI A EVA A RE 249 33 Red HAt NEIWOTK ooe reese EE EEES NE EERE EGE 251 VI Appendixes cssccsssssssssescessssssscsssssesssnsessesssesesecsssessssssscssesssesessasesssessssssasssessssasesssesessesessseens 253 Ac Building a Custom Kerne lssi ieina eria EASE Aa RAEE 255 A 1 Building a Modularized Kernel ccc ee ceeeseseseecseeeeesesseseseeeeeaeaes 255 A 2 Making an initrd IMa ges ororen oiia E E EERS A 3 Configuring the Boot Loader A 4 Building a Monolithic Kernel A5 Additional RESOUTCES sser eeii sensorio eraras sesiis EEr aS AEEA V NEEESE 260 B Getting Started with Gnu Privacy Guard 261 B 1 An Introduction to GnuPG 261 B 2 Warning Messages B 3 Generating a Keypair B 4 Generating a Revocation Certificate B 5 Exporting your Publ
312. ser can select to forget the cached authentication by clicking on the icon and selecting the option to forget authentication 22 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 Simply add the user s to the floppy group using the tool of your choice Here is an example showing how gpasswd can be used to add user fred to the floppy group root bigdog root gpasswd a fred floppy Adding user fred to group floppy root bigdog root Now user fred will now be able to access the system s diskette drive from the console 3 redhat Chapter 23 Time and Date Configuration Time and Date Properties Tool allows the user to change the system date and time to configure 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 start the application from the desktop go to the Main Menu Button on the Panel gt System Settings gt Date amp Time or type the command redhat config date at a shell prompt for example in an XTerm or a GNOME terminal 23 1 Time and Date Properties As shown in Figure 23 1 the first tabbed window that appears is for configuring the system date and time and the NTP daemon ntpd Time 4 2002 gt
313. server If you want to allow resources such as RealAudio while still blocking access to normal system services choose Medium Select Customize to allow specific services through the firewall ote If you select a medium or high firewall network authentication methods NIS and LDAP will not work No Firewall No 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 Choose Customize to add trusted devices or to allow additional incoming services Trusted Devices 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 connected 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 put the ppp0 interface is still firewalled If you want to restrict traffic on an interface leave it unchecked Chapter 12 Basic Firewall Configuration 107 It is not recommended that you make any device that is connected to public networks such as the Internet a Trusted Device Allow Incoming Enabling these options allow the specified services to pass
314. 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 152 Chapter 18 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 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 In the Aliases section click Add to add a host name alias Adding an alias here adds a ServerAlias directive within the NameVirtualHost directive 18 3 1 2 SSL rote You can not use name based v
315. side 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 P This will free up 5 540 Kilobytes of diskspace Show Details X Cancel Continue Figure 32 4 Package Removal Summary Click Continue to start the removal process When it is finished an Update Complete message will appear Qrip 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 250 Chapter 32 Package Management Tool 3 redhat Chapter 33 Red Hat Network Red Hat Network is an Internet solution for managing a Red Hat Linux system or a network of Red Hat Linux systems All Security Alerts Bug Fix Alerts and Enhancement Alerts collective known as Errata Alerts can be downloaded directly from Red Hat using the Red Hat Update Agent standalone applicatio
316. sing Network Configurator to configure a network interface to use DHCP 17 4 Additional Resources For configuration options not covered here please refer to the following resources 17 4 1 Installed Documentation dhcpd man page describes how the DHCP daemon works e dhcpd conf man page explains how to configure the DHCP configuration file includes some examples dhcpd leases man page explains how to configure the DHCP leases file includes some ex amples e 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 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 17 Dynamic Host Configuration Protocol DHCP 141 17 4 2 Useful Websites http www linuxdoc org HOWTO mini DHCP index html DHCP mini HOWTO from the Linux Documentation Project 142 Chapter 17 Dynamic Host Configuration Protocol DHCP 3 redhat Chapter 18 Apache HTTP Server Configuration The Apache HTTP Server has been updated to version 2 0 and the package has been renamed httpd The configuration options have changed 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 Official Red Hat Linux Reference Guide for
317. siod 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 Drip 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 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 yo
318. 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 share name with your username If the u 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 You can also use Nautilus to view available Samba shares on your network On the GNOME desktop go to the Main Menu Button on the Panel gt Programs gt Applications gt Nautilus to open a Nautilus window Type smb in the Location bar As shown in Figure 16 1 you will see an icon for each available SMB workgroups on your network To access one double click the icon for it File Edit View Go Bookmarks Help a gt TORQ B oO Back Forward Up Stop Reload Home 2 Location smb j TOE View as coms Y 3 MILLCREEK MINE MSHOME MYGROUP oae eneme a SUPPORT Figure 16 1 SMB Browser in Nautilus If the SMB share you are connecting to requires a user name and password combination you must specify them in the Location bar using the following syntax replace user password server name and sharename with the appropriate values smb user password servername sharename 16 4 Additional Resources For configuration options not covered here please refer to the following resources 134 Chapter 16 Samba 16 4 1 Installed Documentation smb co
319. specified Efon 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 redhat com rw misc export speedy redhat com rw The first line grants users from speedy redhat com read write access and denies all other users The second line grants users from speedy redhat 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 15 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 Series of machines specified with wild cards Use the or character to specify a string match For example 192 168 100 specifies any IP address that begins with 192 168 100 When spec ifying wild cards in fully qualified domain names dots are not included in the wild card 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
320. ssful you will see the following Preparing AEE AE EAE AE AE AE AE AE ARE AE AE aE AE AE AE aE AE ARE AEA AP aE AEE EEE HEE HE aE AE AEA 1005 1 foo AEAEE AE AE E AE AE AE AE AE E AE E aE E AE E AE E AE AE AE AE AE AE EAEE EEEE EE E 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 when installing or upgrading a package If verifying the signature fails you will see an error message such as error V3 DSA signature BAD key ID 0352860f If is it a new header only signature you will see an error message such as Chapter 31 Package Management with RPM 237 error Header V3 DSA signature BAD key ID 0352860f If you do not have the appropriate key installed to verify the signature the message will contain NOKEY such as warning V3 DSA signature NOKEY key ID 0352860f Refer to Section 31 3 for more information on checking a package s signature rote If you are installing a kernel package you should use rpm ivh instead Refer to Chapter 29 for details Installing packages is designed to be simple but you may sometimes see errors 31 2 2 1 Package Already Installed If the package of the same version is already installed you will see Preparing HAAR AT AE AE AE AE AE AE RARE ARETE AE AE AEAEE EH RATHER 1005 package foo 1 0 1 is alrea
321. ssyes 7 2 Installation Method 7 3 Boot Loader Options 7 4 Partition Information 7 5 Network Configuration 65 7 6 Authentication 66 7 7 Firewall Configuration 67 7 8 X Configuration 68 7 9 Package Selection 71 7 10 Pre Installation Script js einir teret srie eitte a SEREI ES ERTE A 72 FAI Postalnstallation Seiph ensnsnianny ni aa 72 PADS avin the Flean er EN eE E E EA Es 74 8 3 Booting Single User Mode wall 9 Software RAID Configuration a9 10 LVM Configuration 83 II Network Related Configuration ssssccssssssssssssssssssscssssssssssscssssssssesssssesessssesssssssseesseseseee 87 11 Network Configuration sesioen ete dbce E TEE A VA E dione 89 11 1 Overview 11 2 Establishing an Ethernet Connection ccs cee ceescseeeeceeseseseecseseseeeees 89 11 3 Establishing an ISDN Connection z 11 4 Establishing a Modem Connection s ss ssssssssessssstsssessssrersssrsresesressnrnsreresesresre 11 5 Establishing an xDSL Connection ee ceeeceeeeeeeeeesesceeeeceesesesseecaeseseeeees 11 6 Establishing a Token Ring Connection 96 11 7 Establishing a CIPE Connection 97 11 8 Establishing a Wireless Connection e 11 9 Managing Hosts 99 11 10 Managing DNS Settings 11 11 Activating Devices 101 11 12 Working with Profiles 101 11 13 Device Aliases 12 Basic Firewall Configuration
322. start 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 Chapter 6 Kickstart Installations 57 6 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 Linux CD ROMs with the same directory structure If you are performing a CD based installation insert the Red Hat Linux CD ROM 1 into the com puter before starting the kickstart installation If you are performing a hard drive installation make sure the ISO images of the binary Red Hat 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 Official Red Hat Linux Installation Guide for details 6 10 Starting a Kickstart Installation To begin a kickstart installation you must boot the system from a Red Hat Linux boot diskette or the CD ROM and enter a special boot command at the boot prompt If the kickstart file is located on a boot diskette that was created f
323. start installation you must have a BOOTP DHCP server on your network and it must include configuration information for the machine on which you are attempt ing to install Red Hat 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 on the BOOTP DHCP server you use Here is an example of a line from the dhcpd conf file for the DHCP server shipped with Red Hat Linux 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 kick
324. sysv chkconfig or Services Config uration Tool to enable it at runtime Refer to Chapter 13 for details rip Read usr share doc samba lt version gt docs htmldocs ENCRYPTION html to learn more about encrypted passwords replace lt version gt with the version number of Samba that you have installed 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 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 Chapter 16 Samba 133 16 3 Connecting to a Samba Share To connect to a Linux Samba share from a Microsoft Windows machine use Network Neighborhood or Windows Explorer To connect to a Samba share from a Linux system from a shell prompt type the following command smbclient hostname sharename U username You will need to replace host name with the hostname or IP address of the Samba server you want to connect to sharename with the name of the shared directory you want to browse and username 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
325. t Linux Reference Guide 176 Chapter 21 Mail Transport Agent MTA Configuration System Configuration gt eae Chapter 22 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 will own the files In contrast every user who logs in at the console will be allowed 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 22 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 If you would like to completely disable this ability you will need to comment out the following line in etc inittab by
326. t a prompt if you created a key without a password you will be asked for more information The computer s output and a set of inputs looks like the following you will need to provide the correct information for your organization and host 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 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 will be created in etc httpd conf ssl crt server crt You will need to restart your secure server after generating the certificate with following the command sbin service httpd restart 19 9 Testing Your Certificate When the secure server is installed by the Red Hat Linux installation program a random key and a generic certificate are installed for testing purposes You can connect to your secure server using this certifica
327. t entry 100 Active Profile Common iz New Devices Hardware Hosts DNS 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 127 0 0 1 localhost localdomain localhost Edit Delete G Hep Apply X Close Figure 11 14 Hosts Configuration rip Chapter 11 Network Configuration 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 your system to resolve hostnames and IP addresses using the name servers first If the IP address can not be resolved through the name servers your system looks for the IP address in the etc hosts file 11 10 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 Active Profile Common ied New Devices Hardware Hosts DNS Hostname example redhat com Primary DNS 172 16 1 1 Secondary DNS 172 16 1 2 Tertiary DNS DNS Search Path devel redhat com Edit
328. t file is in the HTTP directory mydir ks cfg the correct boot command would be ks http server example com mydir ks cfg ks floppy The installation program looks for the file ks cfg on a vfat or ext2 filesystem on the floppy in drive dev fd0 58 Chapter 6 Kickstart Installations ks hd lt device gt lt file gt The installation program will mount the filesystem on lt device gt which must be vfat or ext2 and look for the kickstart configuration file as lt file gt in that filesystem for example ks hd sda3 mydir ks cfg ks file lt file gt The installation program will try to read the file lt file gt from the filesystem no mounts will be done This is normally used if the kickstart file is already on the initrd image ks cdrom lt path gt The installation program will look for the kickstart file on CD ROM as file lt lt path gt ks If ks is used alone the installation program will configure the Ethernet card in the system using DHCP The system will use the bootServer from the DHCP response as an NFS server to read the kickstart file from by default this is the same as the DHCP server The name of the kickstart file is one of the following 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 d
329. t the new kernel by default set the default variable to the value of label in the image section for the new kernel You must run the sbin 1ilo command as root to enable the changes After running it you will see output similar to the following Added linux The after 1inux means that the section labeled 1inux is the default kernel that LILO will boot You can begin testing your new kernel by rebooting your computer and watching the messages to ensure your hardware is detected properly 230 Chapter 29 Upgrading the Kernel 3 redhat Chapter 30 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 is dynamically loaded into memory After a specified period of inactivity the module may be removed from memory When you install Red Hat Linux the hardware on your system is probed and you provide information about how the system will be typically used and which programs should be loaded Based on this probing and the information you provide 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 you build your own custom kernel you can make all of these decisions for yourself If you add new hardware after installation and the hardware requires a kernel mo
330. tart mb Make a partition without creating a new file end mb system move minor num start mb end mb Move the partition Display the partition table Quit parted resize minor num start mb end mb Resize the partition from st art mb to end mb rm minor num Remove the partition mkpartfs part type fs type start mb Make a partition and create the specified file end mb system 30 Chapter 5 Managing Disk Storage Command Description 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 will appear Disk geometry for dev hda 0 000 9765 492 megabytes Disk label type msdos Minor Start End Type Filesystem Flags Si 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 hda1 The Start and End values are in megabytes The Type is one of primary extended or logical The Filesystem is the file system
331. te For any purposes other than testing however you need to get a certificate from a CA or generate a self signed certificate See Section 19 5 if you need more information on the different types of certificates available If you have purchased a certificate from a CA or generated a self signed certificate you should have a file named etc httpd conf ssl key server key containing your key and a file named 166 Chapter 19 Apache HTTP Secure Server Configuration etc httpd conf ssl crt server crt containing your certificate If your key and certificate are somewhere else move them to these directories If you changed any of the default locations or filenames for the secure Web server in your Apache HTTP Server configuration files you should put these two files in the appropriate directory based on your modifications Once these CA files have been moved restart your server with the command sbin service httpd restart If your key file is encrypted you will be asked for the password Type in your password to start your server Point your Web browser to your server s home page The URL to access your secure Web server will look like this https your_domain ote 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 will probably automat ically accept the certificate without prompting you for input and create the secure
332. ted for version 2 0 Console Access How to use the pam_timestamp module has been added Log Files This new chapter contains information on how to examine log files with the Log Viewer Package Management Tool The Gnome RPM application has been replaced with Package Management Tool which this new chapter discusses 2 Document Conventions When you read this manual you will see that certain words are represented in different fonts type faces 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 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 filenames In these cases they are considered to be part of the command so the entire phrase will be 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 filename Filenames 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 Red Hat Li
333. ted 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 Chapter 25 Gathering System Information 193 you do not want to see the totals for all 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 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 25 2 25 3 1 Monitoring File Systems Red Hat Linux provides a utility called diskcheck that monitors the amount of free disk space on the system Based on the configuration file it will send email to the system administrator when one or more disk drives reach a specified capacity To use this utility you must have the diskcheck RPM package installed This utility is run as an hourly cron task The following variables can be defined in etc diskcheck conf defaultCutoff When disk drives
334. ter 6 Kickstart Installations 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 filesystem type for the RAID array Valid values are ext2 ext3 swap and vfat noformat Do not format the RAID array 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 system 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
335. terface which e includes a panel desktop system icons and a graphical file manager KDE Desktop Environment 58 58 Details of KDE is a powerful graphical user interface which includes We a panel desktop system icons and a graphical file manager Applications in x Editors 5 5 Detail Sometimes called text editors these are programs that Total install size 4 750 Megabytes Aa amp Cancel i Update Figure 32 1 Package Management Tool The interface for this application is similar to the one used during installation Packages are divided into package groups 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 248 Chapter 32 Package Management
336. that is readable by a Microsoft Windows system Click Next to continue Configure a Windows Print Queue Configure the SMB share of your remote printer Share User imachinename sharename guest Host IP Password 192 168 1 9 waaneeenaananaane Workgroup devel C Translate n gt r in X amp Cancel Back Figure 26 8 Choosing the Print Server The next step is to select the type of printer that is connected to the remote SMB system Skip to Section 26 6 to continue rote If you require a username and password for an SMB LAN Manager print queue they are stored unencrypted in the spool directory which only root or lp may read 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 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 SMB server it is recommended that they also use a different password than the one for the print queue 26 4 Adding a Novell NetWare NCP Printer To add a Novell NetWare NCP printer click the New button in the main Printer Configuration Tool window The window shown in Figure 26 1 will appear Click Next to proceed You will see the screen shown in Fi
337. the service is running use the command sbin service atd status 27 3 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 of 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 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 in five days 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 Chapter 27 Automated Tasks 219 line and type Ctrl D Alternatively a shell sc
338. the Mail Transport Agent Switcher select Main Menu Button on the Panel gt Extras gt System Settings gt Mail Transport Agent Switcher or type the command redhat switchmail 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 21 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 switchmail nox The Mail Transport Agent Switcher is a tool which enables users to easily switch between various Mail Transport Agent that they have installed Please choose your Mail transport agent Available Mail Transport Agent Sendmail O Postfix Jok X Cancel Figure 21 1 Mail Transport Agent Switcher If you selected Postfix you must make sure the sendmail service is stopped and the post fix service is started sbin service sendmail stop sbin service postfix start If you selected Sendmail you must make sure the post fix service is stopped and the sendmail service is started sbin service postfix stop sbin service sendmail start To enable or disable the services at boot time you must configure the runlevel with Services Config uration Tool ntsysv or chkconfig Refer to Chapter 13 for details For more information about email protocols and MTAs refer to the Official Red Ha
339. the Official Red Hat 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 rip If you use the mkpart fs command instead the file system will be 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 type 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 warning Formatting the partition will permanently destroy any data that currently exists on the partition 32 Chapter 5 Managing Disk Storage 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 label
340. 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 24 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 With 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 in the Red Hat Linux installation program refer to the Chapter 9 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 sup
341. tion 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 34 Chapter 5 Managing Disk Storage Installation Related Information 3 redhat Chapter 6 Kickstart Installations 6 1 What are Kickstart Installations Many system administrators would prefer to use an automated installation method to install Red Hat 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 Red Hat Linux installation Kickstart files can be kept on single server system and read by individual computers during the instal lation This installation method can support the use of a single kickstart file to install Red Hat Linux on multiple machines making it ideal for network and system administrators Kickstart lets you automate a Red Hat Linux installation 6 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
342. tner IP Address of Tunnel Device Server Mode Local Port own choice Remote Peer Address 0 0 0 0 auto 7777 Remote Virtual Address Local Virtual Address Secret Key Configure Tunnel v auto Generate X Cancel Back Forward Figure 11 11 CIPE Settings 98 Chapter 11 Network Configuration 11 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 ESSID mode frequency channel transmit rate and key for your wireless device To add a wireless Ethernet connection follow these steps 1 Click the Devices tab 2 Click the Add button 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 Ethernet card list Otherwise select Other Ethernet Card to add the hardware device rote The installation program usually detects supported wireless Ethernet devices and prompts you to configure them If you configured them during the installation program they will already appear 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 and the device If this is
343. 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 25 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 large 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 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
344. tpd 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 included with Red Hat Linux can provide certain security func tionalities but are not required by the secure server to function 158 Chapter 19 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 will need all of these if you intend to load any extra modules other than the modules provided with this product Please see the Official Red Hat Linux Reference Guide for more information on loading modules onto your secure Web server using Apache s DSO functionality If you do not intend to load other modules onto your Apache server you do not need to install this package httpd manual The httpd manual package contains the Apache Project s Apache User s Guide in HTML format This manual is also available on the Web at http httpd apache org docs
345. ts are written for people interested in contributing to the kernel source code and understanding how the kernel works A 5 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 Ikml The linux kernel mailing list 3 redhat Appendix B Getting Started with Gnu Privacy Guard B 1 An Introduction to GnuPG Have you ever wondered if your email can be read during its transmission from you to other people or from other people to you Unfortunately complete strangers could conceivably intercept or even tamper with your email In traditional also known as snail mail letters are usually sealed within envelopes stamped and delivered from post office branch to branch until they reach their destination But sending mail through the Internet is much less secure email is usually transmitted as unencrypted text from server to server No special steps are taken to protect your correspondence from being seen or tampered with by other people To help you protect your privacy Red Hat Linux 8 0 includes GnuPG the GNU Privacy Guard which is installed by default during a typical Red Hat Linux installation It is also referred to as GPG GnuPG is a tool for secure communication it is a complete and free replacement for the encryption technology of PGP Pretty Good Privacy a widely popular encryption application Usin
346. ttpd conf 143 etc named custom 169 etc printcap 197 etc printcap local 197 etc sysconfig dhepd 139 etc sysconfig iptables 108 110 proc directory 195 var spool cron 216 A anacron additional resources 220 Apache HTTP Secure Server accessing 166 books 167 certificate authorities 161 choosing a CA 161 creation of request 163 installing 165 moving it after an upgrade 160 pre existing 160 self signed 165 test vs signed vs self signed 161 testing 165 connecting to 166 explanation of security 159 installed docs 167 installing 157 key generating 162 packages 157 port numbers 166 providing a certificate for 159 security explanation of 159 upgrading from 1 0 or 2 0 160 URLs 166 URLs for 166 websites 167 Apache HTTP Server See HTTP Configuration Tool additional resources 156 related books 156 securing 159 APXS 158 at 218 additional resources 220 autofs 126 etc auto master 126 Automated Tasks 215 B batch 218 additional resources 220 BIND configuration 169 adding a forward master zone 170 adding a reverse master zone 171 adding a slave zone 173 applying changes 169 default directory 169 boot diskette 225 booting emergency mode 77 rescue mode 75 single user mode 77 Cc CA See Apache HTTP Secure Server chkconfig 116 CIPE connection See network connection command line options printing from 212 configuration console access 179 NFS
347. type which can 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 Qrp 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 y E 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 Start parted where dev hda is the device on which to create the partition parted dev hda Chapter 5 Managing Disk Storage 31 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 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 Partitions in
348. u exchanged your public key will also have to be informed of its expiration and supplied with a new public key If you do not choose an expiration date you will be asked to confirm your decision Press y to confirm your decision Your next task is to provide a user ID that consists of your name your email address and an optional comment When you are finished you will be presented with a summary of the information you entered Once you accept your choices you will have to enter a passphrase rip Like your account passwords a good passphrase is essential for optimal security in GnuPG For example mix your passphrase with uppercase and lowercase letters use numbers or punctuation marks Once you enter and verify your passphrase your keys will be generated You will see a message similar to the following We need to generate a lot of random bytes It is a good idea to perform some other action type on the keyboard move the mouse utilize the disks during the prime generation this gives the random number generator a better chance to gain enough entropy Pet tittet FREE EF inent t h at t Eku t REFE FEE EF Fatt tt Baa aia a aa aia da mia sia aia sia aia sia a mia ala a aba sia aa ala sla mla sda sda aia ala aia mia sia a ala sla aa ala aa aia sia aa ais a 444 When the activity on the screen ceases your new keys will be made and placed in the directory gnupg in your home directory To list your keys use the command gpg
349. u 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 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 Chapter 6 Kickstart Installations 41 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 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
350. u want to make any changes to the newly installed file system in the post installation section outside of the chroot environment you must append the directory name with mnt sysimage For example if you check the Run outside of the chroot environment button the previous example needs to be changed to the following echo Hackers will be punished gt mnt sysimage etc motd 7 11 2 Use an Interpreter If you want to specify a scripting language to use to execute your script click the Use an interpreter button and enter the interpreter in the text box beside the button For example usr bin python2 2 can be specified for a Python script This option corresponds to using Spost interpreter usr bin python2 2 in your kickstart file 7 12 Saving the File After you have finished choosing your kickstart options if you want to preview the contents of the kickstart file 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 K System language lang en_US Language modules to install langsupport en_US System keyboard keyboard us System mouse mouse genericps 2 System timezone timezone utc America New_York Root password rootpw iscrypted 1 OvTYluQd N4KvDuvuQutbzSF zl gt X Cancel sae to Fil Figur
351. ul 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 simply verify the package You will be notified of any anomalies At that point you can reinstall the package if necessary Any configuration files that you modified are preserved during reinstallation 236 Chapter 31 Package Management with RPM 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 instructions 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 p
352. ure 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 Certificate Authority or 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 will not be au tomatically accepted by a user s browser the user will be asked by the browser if they want to accept the certificate and create the secure connection See Section 19 5 for more information on the differences between self signed and CA signed certificates 160 Chapter 19 Apache HTTP Secure Server Configuration Once you have a self signed certificate or a signed certificate from the CA of your choice you will need to install it on your secure Web server 19 4 Using Pre Existing Keys and Certificates If you already have an existing key and certificate for example if you are installing the secure Web server to replace another company s secure Web server product you will probably be able to use your existing key and certificate with the secure Web server In the following two situations you will not be able to use your existing key and certificate Ifyou are changing your IP address or domain name You can not use
353. use freshening you will not have to delete any unwanted packages from the group that you downloaded before using RPM In this case you can simply issue the following command rpm Fvh rpm RPM will automatically upgrade only those packages that are already installed 240 Chapter 31 Package Management with RPM 31 2 6 Querying Use the rpm q command to query the database of installed packages The rpm q foo command will print the package name version and release number of the installed package foo foo 2 0 1 rote Notice that we used the package name foo To query a package you will 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 e f lt file gt will query the package which owns lt file gt When specifying a file you must 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
354. use the dummy one provided in Red Hat Linux for your website For details on purchasing a CA approved digital certificate refer to the Chapter 19 Chapter 18 Apache HTTP Server Configuration 153 General Options 4 Enable SSL su Site Gobh guration SSL Configuration Logging Certificate File Jetc httpd confssi crt server c Browse Environment Variables Se Directories Certificate Key File Jetc httpd conf ssl key server v Browse Certificate Chain File jetc httpd conf ssl crt ca crt x Browse Certificate Authority File Jetc httpd conf ssl crt ca bundl Browse SSL Log File logs ssl_engine_log v Browse SSL Log Level Info z sst Options O FakeBasicAuth o ExportCertData oO CompatEnvVars C StrictRequire C _OptRenegotiate Heip Pox amp Cancel Figure 18 9 SSL Support 18 3 1 3 Additional Virtual Host Options The Site Configuration Environment Variables and Directories 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 18 2 for details on these options 18 4 Server Settings The Server tab allows you to configure basic server settings The default settings for these options are appropriate for most situations
355. ver will generate and return a list in HTML format of the subdirectories and files in the directory 146 Chapter 18 Apache HTTP Server Configuration Use the Error Code section to configure Apache HTTP Server to redirect the client to a local or external URL if 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 Web page that you created in a file called 404 html copy 404 html1 to Document Root errors 404 htm1 In this case Document Root is the Document Root directory that you have defined the default is var www htm1 Then choose File as the Behavior for 404 Not Found error code and enter errors 404 htm1 as the Location From the Default Error Page Footer menu you can choose one of the following options Sho
356. vmlinuz 2 4 18 7 95 Added linux Writing boot sector Be sure the messages contains Writing boot sector The after linux means that the section labeled 1inux is the default kernel that LILO will boot From now on when the system boots you will see the old and new entries To boot the new kernel select it and press Enter You can begin testing your new kernel by rebooting your computer and watching the messages to ensure your hardware is detected properly If it is successful you can change LILO to boot the new kernel by default by changing the label after default in the configuration file and running the command lilo v A 4 Building a Monolithic Kernel To build a monolithic kernel follow the same steps as building a modularized kernel with a few exceptions 260 Appendix A Building a Custom Kernel When configuring the kernel do not compile anything as a module In other words only answer Yes or No to the questions Also you should answer No to kmod support and module version CONFIG_MODVERSIONS support Omit the following steps make modules make modules_install Edit lilo conf to include the line append nomodules or append the kernel line in grub conf with nomodules A 5 Additional Resources For more information on the Linux kernel refer to these resources A 5 1 Installed Documentation e usr src linux 2 4 Documentat ion Advanced documentation on the Linux kernel and its modules These documen
357. w 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 18 3 1 1 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 18 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 file var log httpd error_log Site Configuration Transfer Log Logg Environment Variables Directories Log to Program I Log to File logs access_log v Browse Use System Log Use custom logging facilities Custom Log String Error Log Log to File logs error_log d Browse Log to Program Use System Log Log Level Error z Reverse DNS Lookup Reverse Lookup x 8 Help ox amp Cancel Figure 18 4 Logging Chapter 18 Apache HTTP Server Configuration 147 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 informat
358. w in Figure 11 5 appears Select Modem F Modem Properties Modem Device dev ttys y Baud Rate 115200 x Elow Control Hardware CRTSCTS na Modem Volume Off z O Use touch tone dialing X cancel Back Forward Figure 11 5 Modem Settings 6 Configure the baud rate flow control and modem volume If you do not know these values accept the defaults If you do not have touch tone dialing uncheck the corresponding checkbox 7 Click Forward 8 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 the values contact your ISP Click Forward 9 On the Create Dialup Connection page click Apply After configuring the modem device it appears in the device list as shown in Figure 11 6 94 Chapter 11 Network Configuration Active Profile Common T New Devices Hardware Hosts DNS 4c You may configure network devices associated with 4 physical hardware here Multiple logical devices can be P associated with a single piece of hardware Profile Status Device Nickname Type Add v active pppo p ode Edit Copy Delete Activate sl gt Gee Y Apy X close Figure 11 6 Modem Device Be sure to click Apply to
359. xample to set the language to English the kickstart file should contain the following line lang en_US Valid language codes are the following please note that these are subject to change at any time Chapter 6 Kickstart Installations 45 cs_CZ da_DK en_US fr_FR de_DE is_IS it_IT ja_JP eucJP ko_KR eucKR no_NO pt_PT ru_RU koi8r sl_SI es_ES sv_SE uk_UA zh_CN GB18030 zh_TW Big5 langsupport required Sets the language s to install on the system The same language codes used with lang can be used with langsupport If you just want to install one language specify it For example to install and use the French language fr_FR langsupport fr_FR default If you want to install language support for more than one language you must specify a default 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 installed with the specified language set to the default lilo replaced by boot loader warning This option has been replaced by bootloader and is only available for backwards compatibility Refer to boot loader Specifies how the boot loader should be installed on the system By default LILO installs on the MBR of the first disk and installs a dual boot system if a DOS partition is found the DOS Windows system will boot if the user types dos at the LILO prompt
360. xinetd Click on a service to display a brief description of that service at the bottom of the window To start stop or restart a service immediately select the service and choose the action from the Actions pulldown menu You can also select the service and click the start stop or restart button on the toolbar If you select an xinetd service such as telnet the Start Stop and Restart buttons will not be active If you change the Start at Boot value of an xinetd service you must click the Save Changes button to restart xinetd and disable enable the xinetd services that you changed To enable a service at boot time for the currently selected runlevel check the checkbox beside the name of the service under the Start at Boot column After configuring the runlevel you must apply the changes Select File gt Save Changes from the pulldown menu or click the Save Changes button Miva When you save changes to xinetd services xinetd is restarted When you save changes to other services the runlevel is reconfigured but the changes do not take effect immediately 116 Chapter 13 Controlling Access to Services If you check or uncheck the Start at Boot value for a service in etc rc d init d the Save Changes button will become active Click it to reconfigure the currently selected runlevel The changes do not affect the system immediately For example assume you are configuring runlevel 3 If you change the Start at Boot value for the anac
361. xt3 partitions without losing data See the appendix titled Upgrading Your Current System in the Official Red Hat Linux Installation Guide for details The following sections will walk you through the steps for creating and tuning ext3 partitions If you have ext2 partitions and are running Red Hat Linux 8 0 you can skip the partitioning and formating sections below and go directly to Section 1 3 16 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 a Red Hat Linux system you may want to create partition the drive and use the ext3 file system 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 e21label 4 Create the mount point 5 Add the partition to etc fstab Refer to Chapter 5 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
362. y users to console programs you should run this 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 22 3 Disabling All Console Access The PAM pam_console so module manages console file permissions and authentication See the Official Red Hat Linux Reference Guide for more information on configuring PAM If you want to disable all console access including program and file access comment out all lines that refer to pam_console so in the etc pam d directory As root the following script will do the trick cd etc pam d for iin do sed pam_console so s lt i gt foo amp amp mv foo i done 22 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
363. 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 md5sum The output would be like the following asr share doc textutils 2 0a NEWS usr share doc textutils 2 0a README usr info textutils info gz usr man manl cat 1 gz usr man manl cksum 1 gz usr man manl1 comm 1 gz usr man manl csplit 1 gz usr man manl cut 1 gz usr man manl1 expand 1 gz usr man manl1 fmt 1 gz usr man manl1 fold 1 gz usr man manl1 head 1 gz usr man manl1 join 1 gz usr man man1 md5sum 1 gz usr man man1 nl1 1 gz usr man man1 od 1 gz asr man manl paste 1 gz usr man man1 pr 1 gz usr man manl ptx 1 gz usr man manl1 sort 1 gz usr man manl split 1 gz usr man manl sum 1 gz usr man manl tac 1 gz usr man manl1 tail 1 gz usr man man1 tr 1 gz usr man manl tsort 1 gz asr man manl unexpand 1 gz usr man man1 uniq 1 gz usr man manl we 1 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 sndconfig 0 68 3 1386 rpm The output would look like the following Name sndconfig Relocations not relocateable Version 0 68 Vendor Red Hat Release ae Build Date Sun 23 Jun 2002 08 22 52 PM EDT Install date Mon 01 Jul 2002 08 40 06 AM EDT Build Host perf90 perf redhat com Group Applications Multimedia Source RPM sndconfig
364. ype Add v active pppo p D Eat Copy Delete Activate ni D Gre Y apply X close Figure 11 4 ISDN Device Be sure to click Apply 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 be changed When the device is added it is not activated as seen by its Inactive status To activate the device select it from the device list and click the Activate button Chapter 11 Network Configuration 93 11 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 Add button 3 Select Modem connection from the Device Type list and click Forward 4 If there is a modem already configured in the hardware list on the Hardware tab Network Administration Tool assumes you want to use it to establish a modem connection If there is not modem already configured it tries to detect any modems in the system This probe might take a while 5 After probing the windo

Red Hat Linux 8.0 The Official Red Hat Linux Customization Guide

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