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Red Hat Enterprise Linux 4 System Administration

1. New Edit Delete Reset RAID LVM Disk Setup aa Device Mampan rype romat Sa Choose where you would like gt LVM Volume Groups Red Hat Enterprise Linux AS to be installed Y VolGroup00 8512 LogVol02 swap 1024 If you do not know how to LogVol0L home ext3 v 1024 partition your system or if you LogVol00 I ext3 4 5024 need nap wn using ae gt RAID Devices manual partitioning tools refer to the tas pefe aeiia Topot sa S dev md1 VolGroup00 LVM PV vV 8573 75 If you used automatic 7 Hard Drives partitioning you can either Vv dev sda accept the current partition dev sdal dev md0 software RAID 102 1 settings click Next or modify dev sda2 dev mdl software RAID 8574 14 the setup using the manual Jdevisdb panong dev sdbl Idev md0 software RAID 1021 If you are manually partitioning dev sdb2 dev md1 software RAID 8574 14 your system you can see your current hard drive s and 3 2 partitions displayed below Use I Hide RAID device LVM Volume Group members Bide Help Release Notes lt Back Next Figure 10 9 Final Sample RAID With LVM Configuration You can continue with your installation process Refer to the Red Hat Enterprise Linux Installation Guide for further instructions 84 Chapter 10 Software RAID Configuration Chapter 11 Swap Space 11 1 What is Swap Spac
2. Virtual Hosts Name address Add Default Virtual Host Default virtual host Edit Delete Edit Default Settings OK 3 Cancel T Heip Figure 25 8 Virtual Hosts http httpd apache org docs 2 0 vhosts and the Apache HTTP Server documentation on your ma chine provide more information about virtual hosts 25 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 and clicking the Edit button 25 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 lt VirtualHost gt directive The default DocumentRoot is var www html The Webmaster email address corresponds to the ServerAdmin directive within the VirtualHost directive This email address is used in the footer of error pages if you choose to show a footer with an email address on the error pages 204 Chapter 25 Apache HTTP Server Configuration In the Host Information section choose Default Virtua
3. partition your system or if you i need help with using the New Edit Delete Reset RAID LVM manual partitioning tools refer i Mount Point Size to the product documentation Device nannaa e Format yp Start End i PEN Hard Drives p AS fdevisda partitioning you can either akcept ihe caiiehi paniion devisdal software RAID 12 1 2B settings click Next or modify Free Free space 8574 14 1106 the setup using the manual jdevisdb partitioning tool fdevi sdb1 software RAID 1 1 8 Free Free space 8574 14 1106 Ifyou are manually partitioning your system you can see your current hard drive s and partitions displayed below Use Hide RAID device LVM Volume Group members Bride Release Notes lt Back BD Next Bruene SRetease Nos asa gt ne Figure 10 4 RAID 1 Partitions Ready Pre Device and Mount Point Creation 10 2 Creating the RAID Devices and Mount Points Once you have all of your partitions created as software RAID partitions the following steps create the RAID device and mount point 1 Select the RAID button on the Disk Druid main partitioning screen refer to Figure 10 5 2 Figure 10 5 appears Select Create a RAID device RAID Options Software RAID allows you to combine several disks into a larger RAID device A RAID device can be configured to provide additional speed and reliability compared to using an individual drive
4. Devices Hardware IPsec DNS Hosts You may configure the system s hostname domain name servers and search domain Name servers are used to look up other hosts on the network Hostname localhost localdomain Primary DNS 172 16 52 28 Secondary DNS 172 16 52 27 Tertiary DNS DNS Search Path devel redhat com Figure 18 14 DNS Configuration 142 Chapter 18 Network Configuration Note The name servers section does not configure the system to be a name server Instead it configures the name servers to use when resolving IP addresses to hostnames and vice versa 18 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 tries to determine the hostname for an IP address it refers to the etc hosts file before using the name servers if you are using the default Red Hat Enterprise Linux configuration If the IP address is listed in the etc hosts file the name servers are not used If your network contains computers whose IP addresses are not listed in DNS it is recommended that you add them to the etc hosts file To add an entry to the etc hosts file go to the Hosts tab click the New button on the toolbar provide the requested information and click OK Select File gt Save or
5. is Help 3 Cancel lt 4 Back D Eorward Figure 34 8 Adding an NCP Printer Text fields for the following options appear Server The hostname or IP address of the NCP system to which the printer is attached Queue The remote queue for the printer on the NCP system User The name of the user you must log in as to access the printer Password The password for the user specified in the User field above Next select the printer type Refer to Section 34 7 Selecting the Printer Model and Finishing for de tails waming If you require a username and password they are stored unencrypted in files only readable by root and Ipd Thus it is possible for others to learn the username and password if they have root access To avoid this the username and password to access the printer should be different from the username and password used for the user s account on the local Red Hat Enterprise Linux system If they are different then the only possible security compromise would be unauthorized use of the printer If there are file shares from the server it is recommended that they also use a different password than the one for the print queue 34 6 Adding a JetDirect Printer To add a JetDirect printer click the New button in the main Printer Configuration Tool window The window shown in Figure 34 1 appears Click Forward to proceed 264 Chapter 34 Printer Configuration I
6. Figure 2 3 Boot Loader Options GRUB is the default boot loader for Red Hat Enterprise Linux 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 diskette or have another way to boot your system such as a third party boot loader You must choose where to install the boot loader the Master Boot Record or the first sector of the boot partition Install the boot loader on the MBR if you plan to use it as your boot loader To pass any special parameters to the kernel to be used when the system boots enter them in the Kernel parameters text field For example if you have an IDE CD ROM Writer you can tell the kernel to use the SCSI emulation driver that must be loaded before using cdrecord by configuring hdd ide scsi as a kernel parameter where hdd is the CD ROM device You can password protect the GRUB boot loader by configuring a GRUB password Select Use GRUB password and enter a password in the Password field Type the same password in the Confirm Password text field To save the password as an encrypted password in the file select Encrypt GRUB password If the encryption option is selected when the file is saved the plain text password that you typed are encrypted and written to the kickstart file If type an already encrypted password unselect to encrypt it If Upgrade an existing installation is selected on the Installation Met
7. Important Do not edit the etc printcap file or the files in the etc cups directory Each time the printer daemon cups is started or restarted new configuration files are dynamically created The files are dynamically created when changes are applied with the Printer Configuration Tool as well Action Test Help A New Edit Delete Default Apply Queue name Default Description printer my printer Figure 34 1 Printer Configuration Tool The following types of print queues can be configured Locally connected a printer attached directly to the computer through a parallel or USB port Networked CUPS IPP a printer that can be accessed over a TCP IP network via the Internet Printing Protocol also known as IPP for example a printer attached to another Red Hat Enterprise Linux system running CUPS on the network 258 Chapter 34 Printer Configuration Networked UNIX LPD a printer attached to a different UNIX system that can be accessed over a TCP IP network for example a printer attached to another Red Hat Enterprise Linux system running LPD on the network Networked Windows SMB a printer attached to a different system which is sharing a printer over an SMB network for example a printer attached to a Microsoft Windows machine Networked Novell NCP a printer attached to a different system which uses Novell s NetWare network technology Netw
8. Notice that the default is not set to the new kernel To configure z IPL to boot the new kernel by default change the value of the default variable to the name of the section that contains the new kernel The first line of each section contains the name in brackets After modifying the configuration file run the following command as root to enable the changes Chapter 37 Manually Upgrading the Kernel 291 sbin zipl Begin testing the new kernel by rebooting the computer and watching the messages to ensure that the hardware is detected properly 37 6 4 IBM eServer iSeries Systems The boot vmlinitrd lt kernel version gt file is installed when you upgrade the kernel How ever you must use the dd command to configure the system to boot the new kernel 1 As root issue the command cat proc iSeries mf side to determine the default side either A B or C 2 As root issue the following command where lt kernel version gt is the version of the new kernel and lt side gt is the side from the previous command dd if boot vmlinitrd lt kernel version gt of proc iSeries mf lt side gt vmlinux bs 8k Begin testing the new kernel by rebooting the computer and watching the messages to ensure that the hardware is detected properly 37 6 5 IBM eServer pSeries Systems IBM eServer pSeries systems use YABOOT as the boot loader which uses etc aboot conf as the configuration file Confirm that the file contains an image secti
9. The man pages for useradd passwd groupadd and chage 33 7 2 Related Books Red Hat Enterprise Linux Reference Guide This manual gives a list of standard users and groups discusses user private groups and provides an overview of shadow passwords Red Hat Enterprise Linux Introduction to System Administration This companion manual con tains more information on managing users and groups as well as managing user resources 256 Chapter 33 User and Group Configuration Chapter 34 Printer Configuration The Printer Configuration Tool allows users to configure a printer This tool helps maintain the printer configuration file print spool directories and print filters Red Hat Enterprise Linux 4 uses the CUPS printing system If a system was upgraded from a previous Red Hat Enterprise Linux version that used CUPS the upgrade process preserved the configured queues Using the Printer Configuration Tool requires root privileges To start the application select Ap plications the main menu on the panel gt System Settings gt Printing or type the command system config printer This command automatically determines whether to run the graphical or text based version depending on whether the command is executed in the graphical desktop envi ronment or from a text based console To force the Printer Configuration Tool to run as a text based application execute the command system config printer tui from a shell prompt
10. If DHCP is specified and the boot file begins with a the boot file provided by DHCP is looked for on the NFS server If DHCP is specified and the boot file begins with something other then a the boot file provided by DHCP is looked for in the kickstart directory on the NFS server If DHCP did not specify a boot file 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 uses 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 eth1l at the boot prompt 26 Chapter 1 Kickstart Installations Chapter 2 Kickstart Configurator Kickstart Configurator allows you to create or modify a kickstart file using a graphical user interface so that you do not have to remember the correct syntax of the file To use Kickstart Configurator you must be running the X Window System To start Kickstart Configurator select Applications the main menu on the panel gt System Tools gt Kickstart or type the command usr sbin system config kickstart As you are creating a kickstart file you can select File gt Preview at any time to review your current selections To start with an exi
11. 13 2 Managing Disk Quotas If quotas are implemented they need some maintenance mostly in the form of watching to see if the quotas are exceeded and making sure the quotas are accurate Of course if users repeatedly exceeds their quotas or consistently reaches their soft limits a system administrator has a few choices to make depending on what type of users they are and how much disk space impacts their work The administrator can either help the user determine how to use less disk space or increase the user s disk quota if needed 13 2 1 Enabling and Disabling Tt is possible to disable quotas without setting them to be 0 To turn all user and group quotas off use the following command quotaoff vaug If neither the u or g options are specified only the user quotas are disabled If only g is specified only group quotas are disabled Chapter 13 Implementing Disk Quotas 101 To enable quotas again use the quaotaon command with the same options For example to enable user and group quotas for all file systems use the following command quotaon vaug To enable quotas for a specific file system such as home use the following command quotaon vug home If neither the u or g options are specified only the user quotas are enabled If only g is specified only group quotas are enabled 13 2 2 Reporting on Disk Quotas Creating a disk usage report entails running the repquota utility For example the command
12. 18 5 Establishing an xDSL Connection DSL stands for Digital Subscriber Lines There are different types of DSL such as ADSL IDSL and SDSL The Network Administration Tool uses the term xDSL to mean all types of DSL connections Some DSL providers require that the system is configured to obtain an IP address through DHCP with an Ethernet card Some DSL providers require you to configure a PPPoE Point to Point Protocol over Ethernet connection with an Ethernet card Ask your DSL provider which method to use If you are required to use DHCP refer to Section 18 2 Establishing an Ethernet Connection to con figure your Ethernet card If you are required to use PPPoE follow these steps Chapter 18 Network Configuration 137 1 Click the Devices tab 2 Click the New button 3 Select xDSL connection from the Device Type list and click Forward 4 If your Ethernet card is in the hardware list select the Ethernet Device from the pulldown menu from the page shown in Figure 18 8 Otherwise the Select Ethernet Adapter window appears Note The installation program detects supported Ethernet devices and prompts you to configure them If you configured any Ethernet devices during the installation they are displayed in the hardware list on the Hardware tab Configure DSL connection a Select the ethemet device for this account Ethernet Device ethO 82557 8 9 Ethernet Pro 100 w Enter the provider name for this a
13. To perform a pen based flash memory kickstart installation the kickstart file must be named ks cfg and must be located in the flash memory s top level directory Create the boot image first and then copy the ks cfg file For example the following transfers a boot image to the pen drive dev sda using the dd command dd if diskboot img of dev sda bs 1M Chapter 1 Kickstart Installations 23 Note Creation of USB flash memory pen drives for booting is possible but is heavily dependent on system hardware BIOS settings Refer to your hardware manufacturer to see if your system supports booting to alternate devices 1 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 kickstart installation you must have a BOOTP DHCP server on your network and it must include configuration information for the machine on which you are attempting to in
14. Uninstalling a package is just as simple as installing one Type the following command at a shell prompt rpm e foo Note Notice that we used the package name foo not the name of the original package file foo 1 0 1 i386 rpm To uninstall a package replace foo with the actual package name of the original package You can encounter a dependency error when uninstalling a package if another installed package de pends on the one you are trying to remove For example Chapter 15 Package Management with RPM 115 error Failed dependencies foo is needed by installed bar 2 0 20 3 i386 rpm To cause RPM to ignore this error and uninstall the package anyway which may break the package depending on it use the nodeps option 15 2 4 Upgrading Upgrading a package is similar to installing one Type the following command at a shell prompt rpm Uvh foo 2 0 1 i386 rpm As part of upgrading a package RPM automatically uninstalls any old versions of the foo package In fact you may want to always use U to install packages which works even when there are no previous versions of the package installed o You don t want to use the u option for installing kernel packages because RPM replaces the previous kernel package This does not affect a running system but if the new kernel is unable to boot during your next restart there would be no other kernel to boot instead Using the i option adds the kernel to your GRUB boot men
15. For Common Name make sure you type in the real name of your secure server a valid DNS name and not any aliases which the server may have The Email Address should be the email address for the webmaster or system administrator e Avoid special characters like amp and etc Some CAs reject a certificate request which contains a special character If your company name includes an ampersand amp spell it out as and instead of amp e Do not use either of the extra attributes A challenge password and An optional company name To continue without entering these fields just press Enter to accept the blank default for both inputs The file etc httpd conf ssl csr server csr is created when you have finished entering your information This file is your certificate request ready to send to your CA After you have decided on a CA follow the instructions they provide on their website Their instruc tions tell you how to send your certificate request any other documentation that they require and your payment to them After you have fulfilled the CA s requirements they send a certificate to you usually by email Save or cut and paste the certificate that they send you as etc httpd conf ssl crt server crt Be sure to keep a backup of this file 26 8 Creating a Self Signed Certificate You can create your own self signed certificate Note that a self signed certificate does not provide the security guarantees of
16. 3 4 Provide a one word nickname such as ipsecO for the connection and select whether the con Click Forward to start configuring a host to host IPsec connection nection should be automatically activated when the computer starts Click Forward Select Host to Host encryption as the connection type Click Forward Select the type of encryption to use manual or automatic If manual is selected an encryption key must be provided later in the process If automatic is selected the racoon daemon is used to manage the encryption key If racoon is used the ipsec tools package must be installed Click Forward to continue Specify the IP address of the other host If you do not know the IP address of the other system run the command sbin ifconfig lt device gt on the other system where lt device gt is the Ethernet device used to connect to the other host If only one Ethernet card exists in the system the device name is ethO The IP address is the number following the inet addr label Click Forward to continue If manual encryption was selected in step 6 specify the encryption key to use or click Generate to create one Specify an authentication key or click Generate to generate one It can be any combination of numbers and letters Click Forward to continue Verify the information on the IPsec Summary page and click Apply Select File gt Save to save the configuration Select the IPsec connection
17. APE EE Saha PA TUET ED EA RA EREE fe PAEA ENE sce asta sap EE EAEE te N E a N e is 65537 0x10001 Enter pass phrase You now must enter in a passphrase For security reason it should contain at least eight characters include numbers and or punctuation and it should not be a word in a dictionary Also remember that your passphrase is case sensitive Note You are required to remember and enter this passphrase every time you start your secure server If you forget this passphrase the key must be completely re generated Re type the passphrase to verify that it is correct Once you have typed it in correctly etc httpd conf ssl key server key the file containing your key is created Note that if you do not want to type in a passphrase every time you start your secure server you must use the following two commands instead of make genkey to create the key Use the following command to create your key usr bin openssl genrsa 1024 gt etc httpd conf ssl key server key Then use the following command to make sure the permissions are set correctly for the file chmod go rwx etc httpd conf ssl key server key After you use the above commands to create your key you do not need to use a passphrase to start your secure server QO caution Disabling the passphrase feature for your secure server is a security risk It is not recommended that you disable the passphrase feature for secure server Chapter 26 Apache
18. The command line version can be used in a configuration script or a kickstart script The authentication options are summarized in Table 27 1 These options can also be found in the authconfig man page or by typing authconfig help ata shell prompt Option description O Specify NIS domain krb5adminserver lt server gt Specify Kerberos administration server krb5realm lt realm gt Specify Kerberos realm Chapter 27 Authentication Configuration 227 Option Description O enablekrb5kdcdns Enable use of DNS to find Kerberos KDCs disablekrb5kdcdns Disable use of DNS to find Kerberos KDCs enablekrb5realmdns Enable use of DNS to find Kerberos realms disablekrb5realmdns Disable use of DNS to find Kerberos realms Enable SMB enablesmbauth disablesmbauth Disable SMB smbworkgroup lt workgroup gt Specify SMB workgroup smbservers lt server gt Specify SMB servers enablewinbind Enable winbind for user information by default disablewinbind Disable winbind for user information by default enablewinbindauth Enable winbindauth for authentication by default disablewinbindauth Disable winbindauth for authentication by default smbsecurity lt user server domain ads gt Security mode to use for Samba and winbind smbrealm lt STRING gt Default realm for Samba and winbind when security ads smbidmapuid lt lowest highest gt UID range winbind assigns to domain or ADS
19. The hesiod package must be installed Winbind Select this option to configure the system to connect to a Windows Active Directory or a Windows domain controller User information can be accessed as well as server authentication options can be configured Cache User Information Select this option to enable the name service cache daemon nscd and configure it to start at boot time The nscd package must be installed for this option to work 27 2 Authentication The Authentication tab allows for the configuration of network authentication methods To enable an option click the empty checkbox beside it To disable an option click the checkbox beside it to clear the checkbox Chapter 27 Authentication Configuration User Information Authentication Kerberos Kerberos is a trusted third party authentication system which is commonly used in medium to large networks LDAP The Lightweight Directory Access Protocol is a standard way of searching a directory which can hold arbitrary data in a structured hierarchy LDAP is increasingly being used in small to large networks Z Enable Kerberos Support Configure Kerberos SMB SMB authentication verifies user passwords by attempting to connect to a server which uses the SMB system message block protocol suite Winbind Winbind allows a system to retrieve information about users and to authenticate users by using information stored in an NTDOM or ADS se
20. The ntsysv utility provides a simple interface for activating or deactivating services You can use ntsysv to turn an xinetd managed service on or off You can also use ntsysv to configure runlevels By default only the current runlevel is configured To configure a different runlevel specify one or more runlevels with the level option For example the command ntsysv level 345 con figures runlevels 3 4 and 5 The ntsysv interface works like the text mode installation program Use the up and down arrows to navigate up and down the list The space bar selects unselects services and is also used to press the Ok and Cancel buttons To move between the list of services and the Ok and Cancel buttons use the Tab key A signifies that a service is set to on Pressing the F1 key displays a short description of the selected service A waming Services managed by xinetd are immediately affected by ntsysv For all other services changes do not take effect immediately You must stop or start the individual service with the command service Chapter 20 Controlling Access to Services 161 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 20 5 chkconfig The chkconfig command can also be used to activate and deactivate services The chkconfig list command displays a list of system services and whether th
21. and Enhancement Alerts are issued for all the systems in your network 126 Chapter 17 Red Hat Network File Edit View Go Bookmarks Tools Help E Red Hat Network Errata Relevant al E reo nar network ee aa p Eons a cnn No systems seLecre Manage Clear A Errata Relevant to Your Systems 2 1 20 of 219 gt n Updated Xpef package fixes security issue 2 2005 01 26 a Updated less package fixes security issue 2 2005 01 26 Updated kibS packages fix security vulnerabilities 2 2005 01 19 a painted carnal oa ages ty E e 2 2005 0118 ic Updated ruby package fixes denial of service issue 2 2005 01 17 ic Updated libtiff packages fix security issues 2 2005 0113 a Updated mozilla packages fix a buffer overflow 2 2005 01 13 ic Updated XpeF packages fix security issues 2 2005 01 12 al Updated CUPS packages fix security issues 2 2005 01 12 l a Updated VIN packages fx securty vleraity 2 oa 4 Updated samba packages 2 2008 01 04 Updated aspell packages 2 2005 01 04 Updated ilio packages fix security wiherabites 2 wwa RHSA 2004654 Updated SquirelMail package fixes security vulnerability 2004 12 23 RHBA2004696 Updated BIND packages 2 wema A o eianeson iladan karnal narb anar fw es 2 amma 1393 m Figure 17 2 Relevant Errata e Automatic email notifications Receive an email notification when an Errata Alert is issued for your system s e Scheduled Errata Upda
22. buttons to use a two button mouse as a three button mouse When this option enabled clicking the two mouse buttons simultaneously emulates a middle mouse button click If a serial port mouse is selected click the Serial devices button to configure the correct serial device number such as dev ttys0 for the mouse Click OK to save the new mouse type The selection is written to the file etc sysconfig mouse and the console mouse service gpm is restarted The changes are also written to the X Window Sys tem configuration file etc X11 xorg conf however the mouse type change is not automatically applied to the current X session To enable the new mouse type log out of the graphical desktop and log back in OM To reset the order of the mouse buttons for a left handed user go to Applications the main menu on the panel gt Preferences gt Mouse and select Left handed mouse for the mouse orientation Chapter 32 X Window System Configuration During installation the system s monitor video card and display settings are configured To change any of these settings for the system use the X Configuration Tool To start the X Configuration Tool select Applications the main menu on the panel gt System Set tings gt Display or type the command system config display at a shell prompt for example in an XTerm or GNOME terminal If the X Window System is not running a small version of X is started to run the program A
23. misc export on shadowman example com 22 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 before this command can be executed 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 is mounted from the server 170 Chapter 22 Network File System NFS 22 2 2 Mounting NFS File Systems using autofs A third option for mounting an NFS share is the use of the autofs service 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
24. mount points in the misc directory this relationship would be defined in the etc auto master file Each entry in auto master has three fields The first field is the mount point The second field is the location of the map file and the third field is optional The third field can contain information such as a timeout value For example to mount the directory proj52 on the remote machine penguin example net at the mount point misc myproject on your machine add the following line to auto master misc etc auto misc timeout 60 Next add the following line to etc auto misc myproject rw soft intr rsize 8192 wsize 8192 penguin example net proj52 The first field in etc auto misc is the name of the misc subdirectory This directory is created dynamically by automount It should not actually exist on the client machine The second field con tains mount options such as rw for read and write access The third field is the location of the NFS export including the hostname and directory f Note The directory misc must exist on the local file system There should be no subdirectories in misc on the local file system To start the autofs service at a shell prompt type the following command 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 auto
25. option domain name servers 192 168 113 option time offset 18000 Eastern Standard Time range 192 168 1 10 192 168 1 100 Example 24 1 Subnet Declaration All subnets that share the same physical network should be declared within a shared network dec laration as shown in Example 24 2 Parameters within the shared network but outside the enclosed Chapter 24 Dynamic Host Configuration Protocol DHCP 189 subnet declarations are considered to be global parameters The name of the shared network should be a descriptive title for the network such as using the title 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 0 254 more parameters for EXAMPLE shared network subnet 192 168 1 0 netmask 255 255 252 0 parameters for subnet range 192 168 1 1 192 168 1 254 subnet 192 168 2 0 netmask 255 255 252 0 parameters for subnet range 192 168 2 1 192 168 2 254 Example 24 2 Shared network Declaration As demonstrated in Example 24 3 the group declaration can be used to apply global parameters to a group of declarations For example shared networks subnets and hosts can be grouped group option routers 192 168 1 254 option subnet mask 255 255 2 55 vi0i option domain name example com option domain name servers 19256 16 83 113 option time offset 1800
26. package selection specification 18 part 12 partition 12 post installation configuration 21 poweroff 13 pre installation configuration 19 raid 14 reboot 14 rootpw 15 selinux 15 shutdown 15 skipx 15 text 16 timezone 16 upgrade 16 volgroup 17 what it looks like 1 xconfig 16 zerombr 17 kickstart installations 1 CD ROM based 22 diskette based 22 file format 1 file locations 22 flash based 22 installation tree 23 LVM 10 network based 23 24 starting 24 from a boot CD ROM 24 from CD ROM 1 with a diskette 24 L LDAP 224 225 loading kernel modules 293 log files 281 see also Log Viewer description 281 examining 283 locating 281 rotating 281 syslogd 281 viewing 281 Log Viewer alerts 283 filtering 281 log file locations 282 refresh rate 282 searching 281 logical volume 63 71 logical volume group 63 Logical Volume Manager see LVM logrotate 281 Ipd 258 Ismod 293 lspci 305 LVM 63 additional resources 64 configuring LVM during installation 65 explanation of 63 installing automatic partitioning 65 66 creating a logical volume 71 creating physical volumes 68 creating the boot partition 67 creating volume groups 70 logical volume 63 71 logical volume group 63 LVM tools and utilities 94 physical extent 71 physical volume 63 68 volume groups 70 with kickstart 10 LVM2 explanation of 64 325 Mail Transport Agent see MTA Mail Tr
27. packages dependencies 114 determining file ownership with 119 finding deleted files from 118 freshening with RPM 115 installing 112 with Package Management Tool 122 locating documentation for 119 obtaining list of files 119 preserving configuration files 115 querying 116 querying uninstalled 119 removing 114 with Package Management Tool 123 tips 118 upgrading 115 verifying 117 pam_smbpass 182 pam_timestamp 233 parted 89 creating partitions 91 overview 89 removing partitions 93 resizing partitions 93 selecting device 91 table of commands 89 viewing partition table 90 partition table viewing 90 partitions creating 91 formating mkfs 92 labeling e2label 92 making mkpart 91 removing 93 resizing 93 viewing list 90 password aging 251 forcing expiration of 251 PCI devices listing 305 physical extent 71 physical volume 63 68 pixels 243 postfix 297 PPPoE 136 Pre Execution Environment 43 327 printconf see printer configuration printer configuration 257 adding CUPS IPP printer 259 IPP printer 259 JetDirect printer 263 local printer 258 LPD printer 260 Novell NetWare NCP printer 263 Samba SMB printer 261 cancel print job 272 command line options 269 add a printer 269 remove a printer 269 restore configuration 268 save configuration 268 setting default printer 270 CUPS 257 default printer 266 delete existing printer 266 drive
28. self signed certificate continue to Section 26 8 Creating a Self Signed Certificate 26 7 Generating a Certificate Request to Send toaCA Once you have created a key the next step is to generate a certificate request which you need to send to the CA of your choice Make sure you are in the usr share ssl certs directory and type the following command make certreq Your system displays the following output and asks you for your passphrase unless you disabled the passphrase option umask 77 usr bin openssl req new key etc httpd conf ssl key server key out etc httpd conf ssl csr server csr Using configuration from usr share ssl openssl cnf Enter pass phrase Type in the passphrase that you chose when you were generating your key unless you don t need to Next your system displays some instructions and then ask for a series of responses from you Your inputs are incorporated into the certificate request The display with example responses looks similar to the following You are about to be asked to enter information that will be incorporated into your certificate request What you are about to enter is what is called a Distinguished Name or a DN There are quite a few fields but you can leave some blank For some fields there will be a default value If you enter the field will be left blank Country Name 2 letter code GB US State or Province Name full name Berkshire North Carolina Locality N
29. ssh authorized_keys2 ssh known_hosts2 and etc ssh_known_hosts2 are obsolete SSH Protocol 1 and 2 share the ssh authorized_keys ssh known_hosts and etc ssh ssh_known_hosts files Red Hat Enterprise Linux 4 uses SSH Protocol 2 and RSA keys by default If you reinstall and 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 166 Chapter 21 OpenSSH 21 3 4 1 Generating an RSA Key Pair for Version 2 Use the following steps to generate an RSA key pair for version 2 of the SSH protocol This is the default starting with OpenSSH 2 9 1 To generate an RSA key pair to work with version 2 of the protocol type the following command at a shell prompt ssh keygen t rsa Accept the default file location of ssh id_rsa Enter a passphrase different from your account password and confirm it by entering it again The public key is written to ssh id_rsa pub The private key is written to ssh id_rsa Never distribute your private key to anyone 2 Change the permissions of the ssh directory using the following command chmod 755 ssh 3 Copy the contents of ssh id_rsa pub into the file ssh authorized_keys on the machine to which you want to connect If the file ssh authorized_keys exist append the contents of the file ssh id_rsa
30. user interface GNOME Desktop Environment 34 34 Details GNOME is a powerful graphical user interface which includes a panel desktop system icons and a graphical file manager we KDE Desktop Environment 0 15 gt KDE is a powerful graphical user interface which includes S038 a panel desktop system icons and a graphical file or manager Applications O Editors 0 3 _Sometimes called text editors these are programs that X Total install size 1 369 Megabytes Update Figure 16 1 Package Management Tool The interface for this application is similar to the one used for individual package selection during installation Packages are divided into package groups 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 link beside it Individual pa
31. 155 ISDN connection see network configuration 324 K Kerberos 225 kernel downloading 287 large memory support 285 modules 293 multiple processor support 285 upgrading 285 kernel modules etc rc modules 295 listing 293 loading 294 persistent loading 295 unload 294 keyboard configuring 239 Keyboard Configuration Tool 239 keyboards 239 configuration 239 kickstart how the file is found 24 Kickstart Configurator 27 opost script 41 opre script 40 authentication options 35 basic options 27 boot loader 30 boot loader options 30 Display configuration 36 firewall configuration 35 installation method selection 29 interactive 28 keyboard 27 language 27 language support 28 mouse 27 network configuration 34 package selection 39 partitioning 31 software RAID 32 preview 27 reboot 28 root password 28 encrypt 28 saving 42 SELinux configuration 36 text mode installation 28 time zone 27 kickstart file include 17 post 21 pre 19 auth 2 authconfig 2 autopart 2 autostep 2 bootloader 5 CD ROM based 22 clearpart 5 cmdline 6 creating 2 device 6 diskette based 22 driverdisk 6 firewall 7 firstboot 7 flash based 22 format of 1 halt 8 include contents of another file 17 install 8 installation methods 8 interactive 9 keyboard 9 lang 9 langsupport 9 logvol 10 mouse 10 network 10 network based 23 24 options 2 partitioning examples 18
32. 2 2 Command Line Configuration The Samba Server Configuration Tool is a graphical interface for managing Samba shares users and basic server settings It modifies the configuration files in the etc samba directory Any changes to these files not made using the application are preserved To use this application you must be running the X Window System have root privileges and have the system conf ig samba RPM package installed To start the Samba Server Configuration Tool from the desktop go to the Main Menu Button on the Panel gt System Settings gt Server Set tings gt Samba or type the command system config samba at a shell prompt for example in an XTerm or a GNOME terminal File Preferences Help B Add Properties Delete Help Directory Permissions Description Figure 23 1 Samba Server Configuration Tool 178 Note The Samba Server Configuration Tool does not display shared printers or the default stanza that allows users to view their own home directories on the Samba server Chapter 23 Samba 23 2 1 1 Configuring Server Settings The first step in configuring a Samba server is to configure the basic settings for the server and a few security options After starting the application select Preferences gt Server Settings from the pulldown menu The Basic tab is displayed as shown in Figure 23 2 Basic Security Workgroup mygroup Descript
33. 94 sleeping 0 stopped 0 zombie Cpu s 2 3 us 0 3 sy 0 0 ni 95 4 id 2 0 wa 0 0 hi 0 0 si Mem 645712k total 613184k used 32528k free 176124k buffers Swap 1310712k total Ok used 1310712k free 226136k cached PID USER PR NI VIRT RES SHR S CPU MEM TIME COMMAND 10456 root 14 1 31408 17m 4828 S 2 3 2 7 158 16 98 X 18110 root 16 0 3032 1052 840 R 0 7 0 2 0 00 07 top 1 root 16 0 3036 560 480 S 0 0 0 1 0 00 98 init 2 root 34 19 0 0 0S 0 0 0 0 0 00 10 ksoftirgd 0 3 root 5 10 0 0 0S 0 0 0 0 0 00 07 events 0 4 root 5 10 0 0 0S 0 0 0 0 0 00 01 khelper 5 root 15 10 0 0 0S 0 0 0 0 0 00 00 kacpid 17 root 5 S10 0 0 0S 0 0 0 0 0 00 00 kblockd 0 18 root 1S 0 0 0 0S 0 0 0 0 0 00 00 khubd 27 root 20 0 0 0 0S 0 0 0 0 0 00 00 pdflush 28 root 15 0 0 0 0S 0 0 0 0 0 01 96 pdflush 30 root 12 10 0 0 0S 0 0 0 0 0 00 00 aio 0 29 root 16 0 0 0 0S 0 0 0 0 0 01 98 kswapd0O 103 root 25 0 0 0 0S 0 0 0 0 0 00 00 kseriod 173 root 23 0 0 0 0S 0 0 0 0 0 00 00 scsi_eh_0O 174 root 15 0 0 0 0S 0 0 0 0 0 00 00 ahc_dv_0 177 root 20 0 0 0 0s 0 0 0 0 0 00 00 scsi_eh_1 To exit top press the q key 302 Chapter 40 Gathering System Information Table 40 1 contains useful interactive commands that you can use with top For more information refer to the top 1 manual page Description Space Immediately refresh the display Display a help sereen k Kill a process You are prompted for the process ID and the signal to send to it Change the number
34. FTP or HTTP installations The install command and the installation method command must be on separate lines cdrom Install from the first CD ROM drive on the system harddrive Install from a Red Hat installation tree on a local drive which must be either vfat or ext2 e partition Partition to install from such as sdb2 e dir Directory containing the RedHat directory of the installation tree For example harddrive partition hdb2 dir tmp install tree nfs Install from the NFS server specified gt BSELVeEr Server from which to install hostname or IP e dir Directory containing the RedHat directory of the installation tree For example nfs server nfsserver example com dir tmp install tree Chapter 1 Kickstart Installations 9 url Install from an installation tree on a remote server via FTP or HTTP For example url uri 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 are 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 Refer to the autostep command keyboard required Sets system keyboard type Here is the list of a
35. For more information on using RAID devices please consult the Red Hat Enterprise Linux AS documentation You currently have 3 software RAID partition s free to use What do you want to do now Create a software RAID partition Create a RAID device default dev mdo Clone a drive to create a RAID device default dev md0 3 Cancel OK Figure 10 5 RAID Options 3 Next Figure 10 6 appears where you can make a RAID device and assign a mount point Chapter 10 Software RAID Configuration 81 Make RAID Device Mount Point boot v File System Type ext3 v RAID Device mdO RAID Level RAIDO v 4 sdal 102 MB RAID Members Mishi MEME Number of spares Cancel amp OK Figure 10 6 Making a RAID Device and Assigning a Mount Point 4 Enter a mount point 5 Choose the file system type for the partition At this point you can either configure a dynamic LVM file system or a traditional static ext2 ext3 file system For more information on configuring LVM on a RAID device select physical volume LVM and then refer to Chapter 8 LVM Configuration If LVM is not required continue on with the following instructions 6 Select a device name such as md0 for the RAID device 7 Choose your RAID level You can choose from RAID 0 RAID 1 and RAID 5 If you need assistance in determining which RAID level
36. L T Reverse order Enter page numbers and or E 1 X groups of pages to print separated by commas 1 2 5 10 12 17 Options Print All pages j Cancel Figure 34 16 Print Verification Window 272 Chapter 34 Printer Configuration To view the list of print jobs in the print spool from a shell prompt type the command 1pq The last few lines 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 34 1 Example of 1pq output If you want to cancel a print job find the job number of the request with the command l1pq and then use the command lprm job number For example lprm 902 would cancel the print job in Example 34 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 prints the text file sample txt The print filter determines what type of file it is and converts it into a format the printer can understand 34 13 Sharing a Printer The Printer Configuration Tool s ability to share configuration options can only be used if you are using the CUPS printing system Allowing users on a different computer on the network to print to a printer configured for your system is called sharing the print
37. Ltd My Company Inc Organizational Unit Name eg section Documentation Common Name your name or server s hostname myhost example com Email Address myemail example com After you provide the correct information a self signed certificate is created in etc httpd conf ssl crt server crt Restart the secure server after generating the certificate with following the command sbin service httpd restart 26 9 Testing The Certificate To test the test certificate installed by default either a CA signed certificate or a self signed certificate point your Web browser to the following home page replacing server example com with your domain name https server example com f Note Note the s after http The https prefix is used for secure HTTP transactions 220 Chapter 26 Apache HTTP Secure Server Configuration If you are using a CA signed certificate from a well known CA your browser probably automatically accepts the certificate without prompting you for input and creates the secure connection Your browser does not automatically recognize a test or a self signed certificate because the certificate is not signed by a CA If you are not using a certificate from a CA follow the instructions provided by your browser to accept the certificate Once your browser accepts the certificate your secure server displays a default home page 26 10 Accessing The Server To access your secure server use a URL similar to
38. Matrox Mystique G200 Matrox Productiva G100 MediaVision Proaxcel 128 Mirage 2 128 Miro CRYSTAL VRX Miro Crystal 10SD with GenDAC Video Card RAM 32 MB v Figure 2 12 X Configuration Video Card 2 8 3 Monitor After configuring the video card click on the Monitor tab as shown in Figure 2 13 Eile Help Basic Configuration Display Configuration Installation Method Configure the X Window System Boot Loader Options General Video Card Monitor Partition Information Proba far monitor Network Configuration pain Monitor 640x480 Authentication i Monitor 800x600 lai Gon iggratian Monitor 1024x768 Monitor 1280x1024 Package Selection Pre Installation Script Post Installation Script Monitor 1400x1050 Monitor 1600x1200 LCD Panel 640x480 LCD Panel 800x600 LCD Panel 1024x768 LCD Panel 1280x800 LCD Panel 1400x1050 LCD Panel 1440x900 LCD Panel 1600x1200 v Use custom monitor sync rates Horizontal Syne He Vertical Sync kHz Figure 2 13 X Configuration Monitor Chapter 2 Kickstart Configurator 39 Probe for monitor is selected by default Accept this default to have the installation program probe for the monitor during installation Probing works for most modern monitors If this option is selected and the installation program cannot successfully probe the monitor the in
39. 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 18 10 appears Select the manufacturer and model of the adapter Select the device name If this is the system s first token ring card select tr if this is the second token ring card select tr1 and so on The Network Administration Tool also allows the user to configure the resources for the adapter Click Forward to continue Chapter 18 Network Configuration Select Token Ring Adapter Adapter IBM Olympic based PCI token ring Device trO Resource IRQ Unknown Cancel D Eorward Figure 18 10 Token Ring Settings 139 6 On the Configure Network Settings page choose between DHCP and static IP address You may specify a hostname for the device If the device receives a dynamic IP address each time the network is started do not specify a hostname Click Forward to continue 7 Click Apply on the Create Tokenring Device page After configuring the token ring device it appears in the device list as shown in Figure 18 11 File Profile Help B B 4 ax New Edit Copy Delete Activate Deactivate Devices Hardware IPsec DNS Hosts jec You may configure network devices associated with 3 o physical hardware here Multiple logical devices can be 9 associated with a sin
40. Red Hat Enterprise Linux Be cause there are numerous ways to manually configure a system with LVM the following example is similar to the default configuration done in Section 8 1 Automatic Partitioning On the Disk Partitioning Setup screen select Manually partition with Disk Druid Chapter 8 LVM Configuration 67 8 2 1 Creating the boot Partition In a typical situation the disk drives are new or formatted clean The following figure Figure 8 2 shows both drives as raw devices with no partitioning configured Disk Setup Drive dev sda 8676 MB Model IBM PSG ST39103LC 1 Free s678 MB Choose where you would like Red Hat Enterprise Linux AS to Drive jdev sdb 8676 MB Model IBM PSG ST39204LC 1 lt Free be installed 8678 MB If you do not know how to partition your system or if you need help with using the L nw ps pie Reset RAID NM manual partitioning tools refer Mount Point Size to the product documentation Deer RAIDVolume TYPE Format yg Start End Hard Drives Ifyou used automatic ie at partitioning you can either accept the current partition Free Free space 8679 11107 settings click Next or modify Y dev sdb the setup using the manual Free Free space 8679 11107 partitioning tool If you are manually partitioning your system you can see your current hard drive s and partitions displayed below Use v
41. Select this option to allow the NFS service to be started by a user other than root This option corresponds to insecure Allow insecure file locking Do not require a lock request This option corresponds to insecure_locks Disable subtree checking If a subdirectory of a file system is exported but the entire file system is not exported the server checks to see if the requested file is in the subdirectory exported This check is called subtree checking Select this option to disable subtree checking If the entire file Chapter 22 Network File System NFS 173 system is exported selecting to disable subtree checking can increase the transfer rate This option corresponds to no_subtree_check 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 root By default the user and group IDs of the root user are both 0 Root squashing maps the user ID 0 and the group ID 0 to the user and group IDs of anonymous so that root on the client does not have root privileges on the NFS server If this option is sele
42. Software RAID performance can excel against Hardware RAID The MD driver in the Linux kernel is an example of a RAID solution that is completely hardware independent The performance of a software based array is dependent on the server CPU performance and load For information on configuring Software RAID during installation refer to the Chapter 10 Software RAID Configuration For those interested in learning more about what Software RAID has to offer here are 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 e Automatic CPU detection to take advantage of certain CPU optimizations 9 4 RAID Levels and Linear Support RAID supports various configurations including levels 0 1 4 5 and linear These RAID types are defined as follows Level 0 RAID level 0 often called striping is a performance oriented striped data mapping technique This means the data being written to the array is broken down into strips and written across the member disks of the array allowing high I O performance at low inherent cost but pro vides no redundancy The storage capacity of a level 0 array is equal to the total capacity of the member disks in a Hardware RAID or the total capacity of member partitions in a Software RAID Level 1 RAID lev
43. System Information 40 5 Additional Resources To learn more about gathering system information refer to the following resources 40 5 1 Installed Documentation ps help Displays a list of options that can be used with ps top manual page Type man top to learn more about top and its many options free manual page type man free to learn more about free and its many options df manual page Type man df to learn more about the df command and its many options e du manual page Type man du to learn more about the du command and its many options e lspci manual page Type man lspci to learn more about the 1spci command and its many options e proc directory The contents of the proc directory can also be used to gather more de tailed system information Refer to the Red Hat Enterprise Linux Reference Guide for additional information about the proc directory 40 5 2 Related Books Red Hat Enterprise Linux Introduction to System Administration Red Hat Inc Includes a chap ter on monitoring resources Chapter 41 OProfile OProfile is a low overhead system wide performance monitoring tool It uses the performance mon itoring hardware on the processor to retrieve information about the kernel and executables on the system such as when memory is referenced the number of L2 cache requests and the number of hardware interrupts received On a Red Hat Enterprise Linux system the oprofile RPM
44. This section must be at the end of the kickstart file after the commands and must start with the spre command You can access the network in the pre section however name service has not been configured at this point so only IP addresses work Note Note that the pre install script is not run in the change root environment interpreter usr bin python Allows you to specify a different scripting language such as Python Replace usr bin python with the scripting language of your choice 20 Chapter 1 Kickstart Installations 1 6 1 Example Here is an example pre section Spre bin sh hds mymedia for file in proc ide h do mymedia cat file media if mymedia disk then hds Shds basename file fi done set Shds numhd echo drivel echo hds cut d f1 drive2 echo hds cut d 2 Write out partition scheme based on whether there are 1 or 2 hard drives if numhd 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 ondisk hdb gt gt tmp part i
45. Tool Note The Security Level Configuration Tool only configures a basic firewall If the system needs more complex rules refer to the Red Hat Enterprise Linux Reference Guide for details on configuring specific iptables rules 154 Chapter 19 Basic Firewall Configuration 19 1 1 Enabling and Disabling the Firewall Select one of the following options Disable firewall Disabling the firewall provides complete access to your system and does no security checking Security checking is the disabling of access to certain services This should only be selected if you are running on a trusted network not the Internet or plan to do more firewall configuration later warming If you have a firewall configured or any customized firewall rules in the etc sysconfig iptables file the file is deleted by selecting Disable firewall and clicking OK to save the changes Enable firewall This option configures the system to reject incoming connections that are not in response to outbound requests such as DNS replies or DHCP requests If access to services running on this machine is needed you can choose to allow specific services through the firewall If you are connecting your system to the Internet but do not plan to run a server this is the safest choice 19 1 2 Trusted Services Enabling options in the Trusted services list allows the specified service to pass through the firewall WWW HTTP The HTTP protocol is used
46. Whether users should only be able to read the files in the shared directory or whether they should be able to read and write to the shared directory On the Access tab select whether to allow only specified users to access the share or whether to allow all Samba users to access the share If you select to allow access to specific users select the users from the list of available Samba users The share is added immediately after clicking OK 23 2 2 Command Line Configuration Samba uses etc samba smb conf as its configuration file If you change this configuration file the changes do not take effect until you restart the Samba daemon with the command service smb restart To specify the Windows workgroup and a brief description of the Samba server edit the following lines in your smb conf file workgroup WORKGROUPNAME server string BRIEF COMMENT ABOUT SERVER Replace WORKGROUPNAME with the name of the Windows workgroup to which this machine should belong The BRIEF COMMENT ABOUT SERVER is optional and is used as the Windows comment about the Samba system To create a Samba share directory on your Linux system add the following section to your smb conf file after modifying it to reflect your needs and your system sharename comment Insert a comment here 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 t
47. a CA signed certificate Refer to Section 26 5 Types of Certificates for more details about certificates Chapter 26 Apache HTTP Secure Server Configuration 219 To make your own self signed certificate first create a random key using the instructions provided in Section 26 6 Generating a Key Once you have a key make sure you are in the usr share ssl certs directory and type the following command make testcert The following output is shown and you are prompted for your passphrase unless you generated a key without a passphrase umask 77 usr bin openssl req new key etc httpd conf ssl key server key x509 days 365 out etc httpd conf ssl crt server crt Using configuration from usr share ssl openssl cnf Enter pass phrase Next you are asked for more information The computer s output and a set of inputs looks like the following provide the correct information for your organization and host 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
48. a Python script This option corresponds to using pre interpreter usr bin python2 2 in your kickstart file O eaution Do not include the spre command It is added for you Chapter 2 Kickstart Configurator 2 11 Post Installation Script Eile Help Basic Configuration Installation Method Boot Loader Options Partition Information Network Configuration Authentication Firewall Configuration Display Configuration Package Selection Pre Installation Script Post4nstallation Script Post nstallation Script Warning An error in this script might cause your kickstart installation to fail Do not include the post command at the beginning LI Run outside of the chroot environment Use an interpreter Type your post script below Figure 2 16 Post Installation Script 41 You can also add commands to execute on the system after the installation is completed If the net work is properly configured in the kickstart file the network is enabled and the script can include commands to access resources on the network To include a post installation script type it in the text area QO caution Do not include the spost command It is added for you For example to change the message of the day for the newly installed system add the following command to the post section echo Hackers will be punished gt etc motd OG More examples can be found in Section 1 7 1 Examples 42 C
49. about OpenSSH see Chapter 21 OpenSSH the Red Hat Enterprise Linux Reference Guide 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 stunnel package provides the Stunnel SSL wrapper Stunnel supports the SSL encryption of TCP connections It provides encryption for non SSL aware daemons and protocols such as POP IMAP and LDAP without requiring any changes to the daemon s code Note Newer implementations of various daemons now provide their services natively over SSL such as dovecot or OpenLDAP s slapd server which may be more desirable than using stunnel For example use of stunnel only provides wrapping of protocols while the native support in OpenLDAP s slapa can also handle in band upgrades for using encryption in response to a StartTLS Client request Chapter 26 Apache HTTP Secure Server Configuration 213 Table 26 1 displays a summary of the secure server packages and whether each package is optional for the installation of a secure server Table 26 1 Security Packages 26 3 An Overview of Certificates and Security Your secure server provides security using a combi
50. boot into rescue mode or unmount any partitions on the device and turn off any swap space on the device Start parted where dev sda is the device on which to create the partition parted dev sda 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 12 1 4 Resizing a Partition for details 12 1 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 the Red Hat Enterprise Linux Installation Guide For example to create a primary partition with an ext3 file system from 1024 megabytes until 2048 megabytes on a hard drive type the following command mkpart primary ext3 1024 2048 If you use the mkpartfs command instead the file system is created after the partition is created However parted does not support creating an ext3 file system Thus if you wish to create an ext3 file system use mkpart and create the file system with the mkfs command as described later mkpartfs works for file system ty
51. by Apache and by other Web servers to serve webpages If you plan on making your Web server publicly available enable this option This option is not required for viewing pages locally or for developing webpages You must have the httpd package installed to serve webpages Enabling WWW HTTP will not open a port for HTTPS the SSL version of HTTP FTP The FTP protocol is used to transfer files between machines on a network If you plan on making your FTP server publicly available enable this option The vsftpd package must be installed for this option to be useful SSH Secure Shell SSH is a suite of tools for logging into and executing commands on a remote ma chine To allow remote access to the machine via ssh enable this option The openssh server package must be installed to access your machine remotely using SSH tools Telnet Telnet is a protocol for logging into remote machines Telnet communications are unencrypted and provide no security from network snooping Allowing incoming Telnet access is not recom mended To allow inbound Telnet access you must have the telnet server package installed Mail SMTP To allow incoming mail delivery through your firewall so that remote hosts can connect 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 configur
52. c devel 6 0 7 1 5 i386 rpm 1386 rpm Eile Edit Help Boot Log RPM Packages Cron Log This log file contains a list of RPM packages installed on Kernel Startup Log amp the system This list is updated daily by an automated cron Mail Log task MySQL Server Log 4Suite 1 0 3 i386 rpm rs News Log Canna 3 7p3 7 EL4 i386 rpm RPM Pack Canna devel 3 7p3 7 EL4 i386 rpm Kea Canna libs 3 7p3 7 EL4 i386 rpm Security Log ElectricFence 2 2 2 19 i386 rpm System Log FreeWnn 1 10pl020 5 i386 rpm Update Agent Log FreeWnn devel 1 10p1020 5 i386 rpm Q Filter E Reset Figure 36 1 Log Viewer Chapter 36 Log Files By default the currently viewable log file is refreshed every 30 seconds To change the refresh rate select Edit gt Preferences from the pulldown menu The window shown in Figure 36 2 appears In the Log Files tab click the up and down arrows beside the refresh rate to change it Click Close to return to the main window The refresh rate is changed immediately To refresh the currently viewable file manually select File gt Refresh Now or press Ctrl R On the Log Files tab in the Preferences the log file locations can be modified Select the log file from the list and click the Edit button Type the new location of the log file or click the Browse button to locate the file location using a file selection dialog Click OK to return to the preferences and click C
53. can invoke powerful queries and verifications on your system If you prefer a graphical interface you can use the Package Management Tool to perform many RPM commands Refer to Chapter 16 Package Management Tool for details During upgrades RPM handles configuration files carefully so that you never lose your customiza tions something that you cannot 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 i Note Because RPM makes changes to your system you must be root to install remove or upgrade an RPM package 15 1 RPM Design Goals To understand how to use RPM it can be helpful to understand RPM s design goals Upgradability Using RPM you can upgrade individual components of your system without completely rein stalling When you get a new release of an operating system based on RPM such as Red Hat Enterprise Linux you do not need to reinstall on your machine as you do with operating systems based on other packaging systems RPM allows intelligent fully automated in place upgrades of your system Configuration files in packages are p
54. conf file Domain The Samba server relies on a Windows NT Primary or Backup Domain Controller to verify the user The server passes the username and password to the Controller and waits for it to return Specify the NetBIOS name of the Primary or Backup Domain Controller in the Authentication Server field The Encrypted Passwords option must be set to Yes if this is selected Server The Samba server tries to verify the username and password combination by passing them to another Samba server If it can not the server tries to verify using the user authentication mode Specify the NetBIOS name of the other Samba server in the Authentication Server field Share Samba users do not have to enter a username and password combination on a per Samba server basis They are not prompted for a username and password until they try to connect to a specific shared directory from a Samba server User Default Samba users must provide a valid username and password on a per Samba server basis Select this option if you want the Windows Username option to work Refer to Section 23 2 1 2 Managing Samba Users for details Encrypt Passwords This option must be enabled if the clients are connecting from a system with Windows 98 Windows NT 4 0 with Service Pack 3 or other more recent versions of Mi crosoft Windows The passwords are transfered between the server and the client in an encrypted format instead of as a plain text word th
55. double click on the RPM icon 16 2 Removing Packages To remove all the packages installed within a package group uncheck the checkbox beside it To remove individual packages click the Details button beside the package group and uncheck the indi vidual packages When you are finished selecting packages to remove click the Update button in the main window The application computes the amount of freed disk space as well as the software package dependencies If other packages depend on the packages you selected to remove they are automatically added to the list of packages to be removed Click the Show Details button to view the list of complete packages to be removed Completed System Preparation 1 packages are queued for removal Q This will free up 1 046 Kilobytes of diskspace Show Details 38 Cancel Continue Figure 16 4 Package Removal Summary Click Continue to start the removal process When it is finished an Update Complete message appears o 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 displays the number of packages to be installed and removed 124 Chapter 16 Package Management Tool Chapter 17 Red Hat Network Red Hat Network is an Internet solution for managing one or more Red Hat Enterprise Linux systems All Security Alerts
56. editor change the desired limits For example Disk quotas for user testuser uid 501 Filesystem blocks soft hard inodes soft hard dev VolGroup00 LogVol02 440436 500000 550000 37418 0 0 To verify that the quota for the user has been set use the command quota testuser 100 Chapter 13 Implementing Disk Quotas 13 1 5 Assigning Quotas per Group Quotas can also be assigned on a per group basis For example to set a group quota for the devel group the group must exist prior to setting the group quota use the command edquota g devel This command displays the existing quota for the group in the text editor Disk quotas for group devel gid 505 Filesystem blocks soft hard inodes soft hard dev VolGroup00 LogVol02 440400 0 0 37418 0 0 Modify the limits save the file and then configure the quota To verify that the group quota has been set use the command quota g devel 13 1 6 Assigning Quotas per File System To assign quotas based on each file system enabled for quotas use the command edquota t Like the other edquota commands this one opens the current quotas for the file system in the text editor Grace period before enforcing soft limits for users Time units may be days hours minutes or seconds Filesystem Block grace period Inode grace period dev mapper VolGroup00 LogVol102 7days 7days Change the block grace period or inode grace period save the changes to the file and exit the text editor
57. explaining how to configure the network this part discusses topics related to networking such as how to allow remote logins share files and directories over the network and set up a Web server Table of Contents 18 Network Configuration cssssssscssesssssessesssssesseeesesssssssessesssesssesssseseesssesssessseseesesasssessessseses 131 19 Basic Firewall Configuration scssssssssssssssssssssessessssssssesesssesseessesesessseesessssassessesasessesesesnses 153 20 Controlling Access to Services sssssssssssssssssssesessssessseessessesesessessesesesssessessseesssesesesessesesese 157 PALO A ee a ARATO T T OIRA EN 22 Network File System NFS PARELEL aE PEL OEE I OEE E E EEE ENE E O E OE ceases 24 Dynamic Host Configuration Protocol DHCP eesesessessosesrercscosoerososseseosesesreoeosesseseseoseeses 187 25 Apache HTTP Server Configuration esesseseeseseeseeresesrescosesrercsooseerosroseseerosreseososrsresesesseeresse 195 26 Apache HTTP Secure Server Configuration essseeseesessereecososresooseseerosooseseosroreseoeosesreseoseseeree 211 27 Authentication Configuration eseesesseseosessseeseososroseososesrerooseseosesroseseosroreseososroreososeeresesroseseess 223 Chapter 18 Network Configuration To communicate with other computers computers must have a network connection This is accom plished by having the operating system recognize an interface card such as Ethernet ISDN mo
58. file file owner andrius group andrius user rw user smoore r group r mask r other r If a directory is specified and it has a default ACL the default ACL is also displayed such as file file owner andrius group andrius user rw user smoore r group r mask r other r default user rwx default user andrius rwx default group r x default mask rwx default other r x 14 5 Archiving File Systems With ACLs A waming The tar and dump commands do not backup ACLs The star utility is similar to the tar utility in that it can be used to generate archives of files however some of its options are different Refer to Table 14 1 for a listing of more commonly used options For all available options refer to the star man page The star package is required to use this utility 106 Chapter 14 Access Control Lists Description Creates an archive file Do not extract the files use in conjunction with x to show what extracting the files does Replaces files in the archive The files are written to the end of the archive file replacing any files with the same path and file name Updates the archive file The files are written to the end of the archive if they do not exist in the archive or if the files are newer than the files of the same name in the archive This option only work if the archive is a file or an unblocked tape that may backspace Extracts the files
59. format group name where group name is the NIS netgroup name 22 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 Chapter 22 Network File System NFS 175 sbin service nfs status Start the NFS daemon with the following command sbin service nfs start Stop the NFS daemon with the following command sbin service nfs stop To start the nfs service at boot time use the command sbin chkconfig level 345 nfs on You can also use chkconf ig ntsysv or the Services Configuration Tool to configure which services start at boot time Refer to Chapter 20 Controlling Access to Services for details 22 4 Additional Resources This chapter discusses the basics of using NFS For more detailed information refer to the following resources 22 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 22 4 2 Useful Websites e http nfs sourceforge net the NFS webpage includes links to the mailing lists and FAQs http www tldp org HOWTO NFS HOWTO index html The Linux NFS HOWTO from the Linux Documentation Project 22 4 3 Related Books Managing NFS and NIS Services by Hal Stern O Reilly amp Associates Inc 176 Chapter 2
60. from the archive If used with U and a file in the archive is older than the corresponding file on the file system the file is not extracted Displays the most important options Displays the least important options Do not strip leading slashes from file names when extracting the files from an archive By default they are striped when files are extracted When creating or extracting archive or restore any ACLs associated with the files and directories Table 14 1 Command Line Options for star 14 6 Compatibility with Older Systems If an ACL has been set on any file on a given file system that file system has the ext_attr attribute This attribute can be seen using the following command tune2fs l1 lt filesystem device gt A file system that has acquired the ext_attr attribute can be mounted with older kernels but those kernels do not enforce any ACLs which have been set Versions of the e2fsck utility included in version 1 22 and higher of the e2f sprogs package includ ing the versions in Red Hat Enterprise Linux 2 1 and 4 can check a file system with the ext_attr attribute Older versions refuse to check it 14 7 Additional Resources Refer to the follow resources for more information 14 7 1 Installed Documentation acl man page Description of ACLs Chapter 14 Access Control Lists 107 getfacl man page Discusses how to get file access control lists e setfacl man page Explains how to
61. installation with the Network Administration Tool system config network Refer to Chapter 18 Network Configuration for details For each Ethernet card on the system click Add Network Device and select the network device and network type for the device Select eth0 to configure the first Ethernet card eth1 for the second Ethernet card and so on Chapter 2 Kickstart Configurator 2 6 Authentication Eile Help Basic Configuration Installation Method Boot Loader Options Partition Information Network Configuration Authentication Configuration Authentication Use Shadow Passwords Use MDS NIS LDAP Kerberos 5 Hesiod SMB Name Switch Cache NIS Authentication C Enable NIS Authentication Firewall Configuration NIE Domain Display Configuration Use broadcast to find NIS serv Package Selection Pre Installation Script Post Installation Script Figure 2 9 Authentication 35 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 allow you to configure the following methods of authen tication NIS LDAP e Kerberos 5 e Hesiod SMB Name Switch Cache These methods are not enabled by default To enable one or more of these methods click the appropri ate tab click the checkb
62. 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 EB nportant If the configuration file is changed the changes do not take effect until the DHCP daemon is restarted with the command service dhcpd restart Qi Instead of changing a DHCP configuration file and restarting the service each time using the omshe11 command provides an interactive way to connect to query and change the configuration of a DHCP server By using omshe11 all changes can be made while the server is running For more information on omshe11 refer to the omshe11 man page In Example 24 1 the routers subnet mask domain name domain name servers and time offset options are used for any host statements declared below it Additionally a subnet can be declared a subnet declaration must be included for every subnet in the network If it is not the DHCP server fails to start In this example there are global options for every DHCP client in the subnet and a range declared Clients are assigned an IP address within the range subnet 192 168 1 0 netmask 255 255 255 0 option routers 192 168 1 254 option subnet mask 255 255 255 0 option domain name example com
63. 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 essentially win the race to access the files The first user to log in at the console owns those files Once the first user logs out the next user who logs in owns the files In contrast every user who logs in at the console is 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 28 1 Disabling Shutdown Via Ctrl Alt Del By default etc inittab specifies that your system is set to shutdown and reboot in response to a Ctrl Alt Del key combination used at the console To completely disable this ability comment out the following line in etc inittab by putting a hash mark in front of it ca ctrlaltdel sbin shutdown t3 r now Alternatively you may want to allow certain non root users the right to shutdown or reboot the system from the console using Ctrl Alt Del You can re
64. 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 Each in dividual connection made to look up each hostname adds up Therefore for your own Web server s 200 Chapter 25 Apache HTTP Server Configuration benefit as well as for the Internet s benefit you should leave this option set to No Reverse Lookup 25 2 3 Environment Variables Use the Environment tab to configure options for specific variables to set pass or unset for CGI scripts Sometimes it is necessary to modify environment variables for CGI scripts or server side include SSI pages The Apache HTTP Server can use the mod_env module to configure the environment variables which are passed to CGI scripts and SSI pages Use the Environment Variables page to configure the directives for this module Use the Set for CGI Scripts section to set an environment variable that is passed to CGI scripts and SSI pages For example to set the environment variable MAXNUM to 50 click the Add button inside the Set for CGI Script section as shown in Figure 25 5 and type MAXNUM in the Environment Variable text field and 50 in the Va
65. no smaller than the amount of RAM in the system and no larger than twice the amount of RAM in the system raid lt id gt The partition is used for software RAID refer to raid pv lt id gt The partition is used for LVM refer to 1ogvo1 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 1 Kickstart Installations 13 onpart Or usepart Put the partition on the already existing device For example partition home onpart hdal puts 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 puts the partition on the second SCSI disk on the system asprimary Forces automatic allocation of the partition as a primary partition or the partitioning fails type replaced by fstype This option is no longer available Use fstype fstype Sets the file system type for the partition Valid values are ext 2 ext3 swap and vfat start Specif
66. of hard drives is allocated to one or more physical volumes A physical volume cannot 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 cannot be on a logical volume group because the boot loader cannot read it If the root partition is on a logical volume create a separate boot partition which is not a part of a volume group Since a physical volume cannot span over multiple drives to span over more than one drive create one or more physical volumes per drive Physical Volume Physical Volume Physical Volume boot 9 1GB 9 1 GB 9 1 GB 75 MB ext3 Logical Volume Group 9 1 GB x 3 75 MB we lt Figure 7 1 Logical Volume Group The logical volume group is divided into logical volumes which are assigned mount points such as home and m and file system types such as ext2 or ext3 When partitions reach their full capacity free space from the logical volume group can be added to the logical volume to increase the size of the partition When a new hard drive is added to the system it can be added to the logical volume group and partitions that are logical volumes can be expanded 64 Chapter 7 Logical Volume Manager LVM Logical Volume Group 9 1 GB x 3 75 MB Logical Volume Logical Volume Free Space home 20 GB 2GB 5 GB Figure 7 2 Logical Volumes On the other hand if a system is partitioned with
67. or hostname of the tftp server which provides the files necessary to start the installation program and the location of the files on the tftp server This is possible because of PXELINUX which is part of the syslinux package The following steps must be performed to prepare for a PXE installation 1 Configure the network NFS FTP HTTP server to export the installation tree 2 Configure the files on the tftp server necessary for PXE booting 3 Configure which hosts are allowed to boot from the PXE configuration 4 Start the tftp service 5 Configure DHCP 6 Boot the client and start the installation 3 1 Setting up the Network Server First configure an NFS FTP or HTTP server to export the entire installation tree for the version and variant of Red Hat Enterprise Linux to be installed Refer to the section Preparing for a Network Installation in the Red Hat Enterprise Linux Installation Guide for detailed instructions 3 2 PXE Boot Configuration The next step is to copy the files necessary to start the installation to the tftp server so they can be found when the client requests them The tftp server is usually the same server as the network server exporting the installation tree To copy these files run the Network Booting Tool on the NFS FTP or HTTP server A separate PXE server is not necessary For the command line version of these instructions refer to Section 3 2 1 Command Line Configuration To use the g
68. or not you want to establish a network connection A network connection is useful if you need to backup files to a different computer or install some RPM packages from a shared network location for example The following message is displayed The rescue environment will now attempt to find your Linux installation and mount it under the directory mnt sysimage You can then make any changes required to your system If you want to proceed with this step choose Continue You can also choose to mount your file systems read only instead of read write by choosing Read only If for some reason this process fails you can choose Skip and this step will be skipped and you will go directly to a command shell If you select Continue it attempts to mount your file system under the directory mnt sysimage If it fails to mount a partition it notifies you If you select Read Only it attempts to mount your file system under the directory mnt sysimage but in read only mode If you select Skip your file system is not mounted Choose Skip if you think your file system is corrupted 1 Refer to the Red Hat Enterprise Linux Installation Guide for more details Chapter 5 Basic System Recovery 55 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 3 00b If you selected Continue to mount
69. package must be installed to use this tool Many processors include dedicated performance monitoring hardware This hardware makes it possi ble to detect when certain events happen such as the requested data not being in cache The hardware normally takes the form of one or more counters that are incremented each time an event takes place When the counter value essentially rolls over an interrupt is generated making it possible to control the amount of detail and therefore overhead produced by performance monitoring OProfile uses this hardware or a timer based substitute in cases where performance monitoring hard ware is not present to collect samples of performance related data each time a counter generates an interrupt These samples are periodically written out to disk later the data contained in these samples can then be used to generate reports on system level and application level performance OProfile is a useful tool but be aware of some limitations when using it Use of shared libraries Samples for code in shared libraries are not attributed to the particular application unless the separate library option is used Performance monitoring samples are inexact When a performance monitoring register triggers a sample the interrupt handling is not precise like a divide by zero exception Due to the out of order execution of instructions by the processor the sample may be recorded on a nearby instruction opre
70. perform a new installation or an up grade If you choose upgrade the Partition Information and Package Selection options are disabled They are not supported for kickstart upgrades Choose the type of kickstart installation or upgrade screen from the following options CD ROM Choose this option to install or upgrade from the Red Hat Enterprise Linux CD ROMs NFS Choose this option to install or upgrade from an NFS shared directory In the text field for the the NFS server enter a fully qualified domain name or IP address For the NFS directory enter the name of the NFS directory that contains the RedHat directory of the installation tree For example if the NFS server contains the directory mirrors redhat i386 RedHat enter mirrors redhat i386 for the NFS directory FTP Choose this option to install or upgrade from an FTP server In the FTP server text field enter a fully qualified domain name or IP address For the FTP directory enter the name of the FTP directory that contains the RedHat directory For example if the FTP server contains the directory mirrors redhat i386 RedHat enter mirrors redhat i386 for the FTP directory If the FTP server requires a username and password specify them as well e HTTP Choose this option to install or upgrade from an HTTP server In the text field for the HTTP server enter the fully qualified domain name or IP address For the HTTP directory enter the name of the HTTP
71. press Ctrl S to save the changes to the etc hosts file The network or network services do not need to be restarted since the current version of the file is referred to each time an address is resolved waming Do not remove the localhost entry Even if the system does not have a network connection or have a network connection running constantly some programs need to connect to the system via the localhost loopback interface File Profile Help S B New Edit Devices Hardware IPsec DNS Hosts You may specify static computer hostname to IP address mappings here If DNS is in use these settings will take precedence over any information it may provide IP Name aliases Figure 18 15 Hosts Configuration Chapter 18 Network Configuration 143 Om To change lookup order edit the etc host conf file The line order hosts bind specifies that etc hosts takes precedence over the name servers Changing the line to order bind hosts configures the system to resolve hostnames and IP addresses using the name servers first If the IP address cannot be resolved through the name servers the system then looks for the IP address in the etc hosts file 18 10 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 devi
72. pub to the file ssh authorized_keys on the other machine 4 Change the permissions of the authorized_keys file using the following command chmod 644 ssh authorized_keys 5 If you are running GNOME skip to Section 21 3 4 4 Configuring ssh agent with GNOME If you are not running the X Window System skip to Section 21 3 4 5 Configuring ssh agent 21 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 Co A passphrase is a string of words and characters used to authenticate a user Passphrases differ from passwords in that you can use spaces or tabs in the passphrase Passphrases are generally longer than passwords because they are usually phrases instead of a single word The public key is written to ssh id_dsa pub The private key is written to ssh id_dsa It is important never to give anyone the private key 2 Change the permissions of the ssh directory with the following command chmod 755 ssh 3 Copy the contents of ssh id_dsa pub into the file ssh authorized_keys on the machine to which you want to connect If the file ssh authorized_keys exist ap
73. restart a service immediately select the service from the list and click the appropriate button on the toolbar or choose the action from the Actions pulldown menu If the service is an xinetd service the action buttons are disabled because they can not be started or stopped individually If you enable disable an xinetd service by checking or unchecking the checkbox next to the service name you must select File gt Save Changes from the pulldown menu to restart xinetd and imme diately enable disable the xinetd service that you changed xinetd is also configured to remember the setting You can enable disable multiple xinetd services at a time and save the changes when you are finished 160 Chapter 20 Controlling Access to Services For example assume you check rsync to enable it in runlevel 3 and then save the changes The rsync service is immediately enabled The next time xinetd is started rsync is still enabled y When you save changes to xinetd services xinetd is restarted and the changes take place imme diately When you save changes to other services the runlevel is reconfigured but the changes do not take effect immediately To enable a non xinetd service to start at boot time for the currently selected runlevel check the checkbox beside the name of the service in the list After configuring the runlevel apply the changes by selecting File gt Save Changes from the pulldown menu The runlevel configuration is changed bu
74. service is disabled and configured not to start at boot time execute the following two commands sbin service ipchains stop sbin chkconfig level 345 ipchains off The Services Configuration Tool can be used to enable or disable the iptables and ipchains services Chapter 20 Controlling Access to Services Maintaining security on your system is extremely important and one approach for this task is to manage access to system services carefully Your system may need to provide open access to particular services for example httpd if you are running a Web server However if you do not need to provide a service you should turn it off to minimize your exposure to possible bug exploits There are several different methods for managing access to system services Decide which method of management to use based on the service your system s configuration and your level of Linux expertise The easiest way to deny access to a service is to turn it off Both the services managed by xinetd and the services in the etc rc d init d hierarchy also known as SysV services can be configured to start or stop using three different applications Services Configuration Tool a graphical application that displays a description of each service displays whether each service is started at boot time for runlevels 3 4 and 5 and allows services to be started stopped and restarted e ntsysv a text based application that allows you to config
75. set file access control lists star man page Explains more about the star utility and its many options 14 7 2 Useful Websites http acl bestbits at Website for ACLs 108 Chapter 14 Access Control Lists lll Package Management All software on a Red Hat Enterprise Linux system is divided into RPM packages which can be installed upgraded or removed This part describes how to manage the RPM packages on a Red Hat Enterprise Linux system using graphical and command line tools Table of Contents 15 Package Management with RPM sccssssssssssssssssssssessssesesessesesesesessssssesessssasevesesesessesesesesee 111 16 Package Management Tool ssssssssssssessssnsesssessesssssssessessseesevesscssessssesesssesessesesesesseseveseses 121 17 Red Hat Network ssssssssssssssssssssssssssssssssscssssessonssssesesssessessssssessasssessesesesssesesessasssessseseanes 125 Chapter 15 Package Management with RPM The RPM Package Manager RPM is an open packaging system available for anyone to use which runs on Red Hat Enterprise Linux as well as other Linux and UNIX systems Red Hat Inc encourages other vendors to use RPM for their own products RPM is distributable under the terms of the GPL For the end user RPM makes system updates easy Installing uninstalling and upgrading RPM pack ages can be accomplished with short commands RPM maintains a database of installed packages and their files so you
76. should contain the mount point for the new partition and the next column should be the file system type for example ext3 or swap If you need more information about the format read the man page with the command man fstab If the fourth column is the word defaults the partition is mounted at boot time To mount the partition without rebooting as root type the command mount work Chapter 12 Managing Disk Storage 93 12 1 3 Removing a Partition waming Do not attempt to remove a partition on a device that is in use Before removing a partition boot into rescue mode or unmount any partitions on the device and turn off any swap space on the device Start parted where dev sda is the device on which to remove the partition parted dev sda View the current partition table to determine the minor number of the partition to remove print Remove the partition with the command rm For example to remove the partition with minor number 3 rm 3 The changes start taking place as soon as you press Enter so review the command before committing to it After removing the partition use the print command to confirm that it is removed from the partition table You should also view the output of cat proc partitions to make sure the kernel knows the partition is removed The last step is to remove it from the etc fstab file Find the line that declares the removed partition and remove it from the file 12 1 4 Resi
77. 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 the HTTP Configuration Tool you must allow access through port 443 under the Main tab gt Available Addresses Refer to Section 25 1 Basic Settings for details Then select the virtual host name in the Virtual Hosts tab click the Edit button choose SSL from the left hand menu and check the Enable SSL Support option as shown in Figure 25 9 The SSL Configuration section is pre configured with the dummy digital certificate The digital certificate provides authentication for your secure Web server and identifies the secure server to client Web browsers You must purchase your own digital certificate Do not use the dummy one provided for your website For details on purchasing a CA approved digital certificate refer to the Chapter 26 Apache HTTP Secure Server Configuration 25 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 25 2 Default Settings for details on these options 206 Chapter 25 Apache HTTP Server Configuration 25 4 Server Settings The Server tab allows you to configure basic server settings Th
78. terminal emulator for the X Window System redhat config soundcard A graphical interface for detecting and configuring sounde Z radhat confio xfraa96_A_oranhicolintarface for canfinurina Emad6 gl gt Package Information Full Name None Size None x Close Figure 16 2 Individual Package Selection After selecting package groups and individual packages to install click the Update button on the main window Information such as the number of packages to be installed and the amount of disk space required to install the packages as well as any package dependencies is displayed in a summary window If there are package dependencies they are 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 Q This will take 1 120 Kilobytes of diskspace Show Details 38 Cancel Continue Figure 16 3 Package Installation Summary Click Continue to start the installation process When it is finished an Update Complete message appears Chapter 16 Package Management Tool 123 Om If you use Nautilus to manage 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
79. the BIOS boot order For example bootloader driveorder sda hda location Specifies where the boot record is written Valid values are the following mbr the default partition installs the boot loader on the first sector of the partition containing the kernel or none do not install the boot loader password Sets the GRUB boot loader password to 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 Similar to password except the password should already be encrypted 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 Note If the clearpart command is used then the onpart command cannot be used on a logical partition all Erases all partitions from the system 6 Chapter 1 Kickstart Installations drives Specifies which drives to clear partitions from For example the following clears all the partitions on the first two drives on the primary IDE controller clearpart drives hda hdb all initlabel Initializes the disk label to the default for your architecture for example msdos for x86 and gpt for Itanium It is useful so that the installation program does not ask if it should i
80. the NTP server until you click OK After clicking OK the configuration is saved and the NTP daemon is started or restarted if it is already running Clicking the OK button applies any changes made to the date and time the NTP daemon settings and the time zone settings It also exits the program Chapter 29 Date and Time Configuration 237 29 3 Time Zone Configuration As shown in Figure 29 3 the third tabbed window that appears is for configuring the system time zone To configure the system time zone click the Time Zone tab The time zone can be changed by either using the interactive map or by choosing the desired time zone from the list below the map To use the map click on the city that represents the desired time zone A red X appears and the time zone selection changes in the list below the map Click OK to apply the changes and exit the program Date amp Time Network Time Protocol Time Zone Please select the nearest city in your timezone Asia Krasnoyarsk Moscow 04 Yenisei River America Montserrat a America Nassau America Nipigon Eastern Time Ontario amp Quebec place America Nome Alaska Time west Alaska 5 gt System clock uses UTC T Heip Cancel 2 OK Figure 29 3 Timezone Properties If your system clock is set to use UTC select the System clock uses UTC option UTC s
81. the boot loader which includes all AMD64 systems 37 6 1 1 GRUB Confirm that the file boot grub grub conf contains a title section with the same version as the kernel package just installed if the kernel smp or kernel hugemem package was installed a section exists for it as well Note that you do not have to rerun grub after making changes to this file NOTICE You have a boot partition This means that all kernel and initrd paths are relative to boot eg root hd0 0 kernel vmlinuz version ro root dev hda2 initrd initrd version img boot dev hda default 1 timeout 10 splashimage hd0 0 grub splash xpm gz title Red Hat Enterprise Linux 2 6 9 5 EL root hd0 0 kernel vmlinuz 2 6 9 5 EL ro root LABEL initrd initrd 2 6 9 5 EL img title Red Hat Enterprise Linux 2 6 9 1 906_EL root hd0 0 kernel vmlinuz 2 6 9 1 906_EL ro root LABEL initrd initrd 2 6 9 1 906_EL img If a separate boot partition was created the paths to the kernel and initrd image are relative to boot Notice that the default is not set to the new kernel To configure GRUB to boot the new kernel by default change the value of the default variable to the title section number for the title section that 290 Chapter 37 Manually Upgrading the Kernel contains the new kernel The count starts with 0 For example if the new kernel is the first title section set default to 0 Begin testing the new kernel by rebooting th
82. the diskless environment such as diskless i386 RHEL4 AS For example mkdir p diskless i386 RHEL4 AS This directory is referred to as the diskless directory 3 Create a subdirectory of this directory named root mkdir p diskless i386 RHEL4 AS root 4 Copy Red Hat Enterprise Linux from the client system to the server using rsync For example rsync a e ssh installed system example com diskless i386 RHEL4 AS root The length of this operation depends on the network connection speed as well as the size of the file system on the installed system Depending on these factors this operation may take a while 5 Start the tftp server as discussed in Section 4 1 Start the t ftp Server 6 Configure the DHCP server as discussed in Section 4 2 Configuring the DHCP Server 7 Finish creating the diskless environment as discussed in Section 4 4 Finish Configuring the Diskless Environment 8 Configure the diskless clients as discussed in Section 4 5 Adding Hosts 9 Configure each diskless client to boot via PXE and boot them 4 1 Start the tftp Server On the DHCP server verify that the tftp server package is installed with the command rpm q tftp server If it is not installed install it via Red Hat Network or the Red Hat Enterprise Linux CD ROMs For more information on installing RPM packages refer to Part III Package Management tftp is an xinetd based service start it with the following commands sbin chkconfig le
83. 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 and the default Red Hat kernel is compiled with LVM support To learn how to configure LVM during the installation process refer to Chapter 8 LVM Configuration 7 2 What is LVM2 LVM version 2 or LVM2 is the default for Red Hat Enterprise Linux which uses the device mapper driver contained in the 2 6 kernel LVM2 which is almost completely compatible with the earlier LVM version can be upgraded from versions of Red Hat Enterprise Linux running the 2 4 kernel Although upgrading from LVMI1 to LVM2 is usually seamless refer to Section 7 3 Additional Resources for further details on more complex requirements and upgrading scenarios 7 3 Additional Resources Use these sources to learn more about LVM 7 3 1 Installed Documentation rpm qd lvm This command shows all the documentation available from the 1vm package including man pages lvm help This command shows all LVM commands available 7 3 2 Useful Websites http sourceware org lvm2 LVM2 webpage which contains an overview link to the mailing lists and more http tldp org HOWTO LVM HOWTO LV
84. the following https server example com Your non secure server can be accessed using an URL similar to the following http server example com The standard port for secure Web communications is port 443 The standard port for non secure Web communications is port 80 The secure server default configuration listens on both of the two standard ports Therefore do not need to specify the port number in a URL the port number is assumed However if you configure your server to listen on a non standard port for example anything other than 80 or 443 you must specify the port number in every URL which is intended to connect to the server on the non standard port For example you may have configured your server so that you have a virtual host running non secured on port 12331 Any URLs intended to connect to that virtual host must specify the port number in the URL The following URL example attempts to connect to a non secure server listening on port 12331 http server example com 12331 26 11 Additional Resources Refer to Section 25 7 Additional Resources for more information about the Apache HTTP Server 26 11 1 Useful Websites http www redhat com mailman listinfo redhat secure server The redhat secure server mailing list You can also subscribe to the redhat secure server mailing list by emailing lt redhat secure server request redhat com gt and include the word subscribe in the subject line http Awww modssl
85. the name of the interface to the list of DHCPDARGS Command line options here DHCPDARGS eth0 This is useful for a firewall machine with two network cards One network card can be configured as a DHCP client to retrieve an IP address to the Internet The other network card can be used as a DHCP server for the internal network behind the firewall Specifying only the network card connected to the internal network makes the system more secure because users can not connect to the daemon via the Internet Other command line options that can be specified in etc sysconfig dhcpd include p lt portnum gt Specify the UDP port number on which dhcpd should listen The default is port 67 The DHCP server transmits responses to the DHCP clients at a port number one greater than the UDP port specified For example if the default port 67 is used the server listens on port 67 for requests and responses to the client on port 68 If a port is specified here and the DHCP relay agent is used the same port on which the DHCP relay agent should listen must be specified Refer to Section 24 2 4 DHCP Relay Agent for details f Run the daemon as a foreground process This is mostly used for debugging d Log the DHCP server daemon to the standard error descriptor This is mostly used for de bugging If this is not specified the log is written to var log messages e cf lt filename gt Specify the location of the configuration file Th
86. this directory Note Even if OProfile is configured not to profile the kernel the SMP kernel still must be running so that the oprofile module can be loaded from it Chapter 41 OProfile 309 Setting whether samples should be collected within the kernel only changes what data is collected not how or where the collected data is stored To generate different sample files for the kernel and application libraries refer to Section 41 2 3 Separating Kernel and User space Profiles 41 2 2 Setting Events to Monitor Most processors contain counters which are used by OProfile to monitor specific events As shown in Table 41 2 the number of counters available depends on the processor 2 2 2 Pf pc tvpowsert Pf type ppc64 970 IBM eServer S 390 and S 390x IBM eServer zSeries Table 41 2 OProfile Processors and Counters Pentium 4 hyper threaded i386 p4 ht Use Table 41 2 to verify that the correct processor type was detected and to determine the number of events that can be monitored simultaneously timer is used as the processor type if the processor does not have supported performance monitoring hardware If timer is used events cannot be set for any processor because the hardware does not have support for hardware performance counters Instead the timer interrupt is used for profiling If timer is not used as the processor type the events monitored can be changed and counter 0 for the processor is set to a time
87. tion is deleted if Red Hat Enterprise Linux is reinstalled or if the same printer configuration is needed on multiple systems The file should be saved on a different system before reinstalling To restore the configuration type this command as root usr sbin system 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 is overwritten If you want to keep your existing configuration and add the configuration in the saved file you can merge the files with the following command as root usr sbin system config printer tui Ximport merge lt settings xml Your printer list then consists 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 Issue the following command as root sbin service cups restart Chapter 34 Printer Configuration 269 34 11 Command Line Configuration If you do not have X installed and you do not want to use the text based version you can add a printer via the command line
88. to create this group unselect Create a private group for the user To specify a user ID for the user select Specify user ID manually If the option is not selected the next available user ID starting with number 500 is assigned to the new user Red Hat Enterprise Linux reserves user IDs below 500 for system users Click OK to create the user User Name tfox Full Name Tammy Fox Password tire Confirm Password sree Login Shell bin bash v lt Create home directory Home Directory home tfox lt Create a private group for the user Specify user ID manually 38 Cancel 2 OK Figure 33 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 33 2 Modifying User Properties for more information To add the user to more user groups click on the User tab select the user and click Properties In the User Properties window select the Groups tab Select the groups that you want the user to be a member of select the primary group for the user and click OK 33 2 Modifying User Properties To view the properties of an existing user click on the Users tab select the user from the user list and click Properties from the menu or choose File gt Properties from the pulldown menu A window similar to Figure 33 3 appears Chapter 33 User and Group Configuration 24
89. to the Firewall Configuration screen in the installation program Refer to Chapter 19 Basic Firewall Configuration for more information If you need more specific firewall rules refer to the iptables chapter in the Red Hat Enterprise Linux Reference Guide 20 1 Runlevels Before you can configure access to services you must understand Linux runlevels A runlevel is a state or mode that is defined by the services listed in the directory etc rc d rc lt x gt d where lt x gt is the number of the runlevel The following runlevels exist e 0 Halt 158 Chapter 20 Controlling Access to Services 1 Single user mode 2 Not used user definable 3 Full multi user mode 4 Not used user definable 5 Full multi user mode with an X based login screen 6 Reboot If you use a text login screen you are operating in runlevel 3 If you use a graphical login screen you are operating in runlevel 5 The default runlevel can be changed by modifying the etc inittab file which contains a line near the top of the file similar to the following id 5 initdefault Change the number in this line to the desired runlevel The change does not take effect until you reboot the system To change the runlevel immediately use the command telinit followed by the runlevel number You must be root to use this command The tel init command does not change the etc inittab file it only changes the runlevel currently ru
90. user home directories UIDs and shells More information 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 hesiod conf This option is used by the Hesiod library to determine the name to search DNS for when looking up informa tion similar to LDAP s use of a base DN hesiodrhs The Hesiod RHS right hand side option set in etc hesiod conf This option is used by the Hesiod library to determine the name to search DNS for when looking up information similar to LDAP s use of a base DN o 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 authenticat
91. users for the system However these permission sets have limitations For example different permissions cannot be configured for different users Thus Access Control Lists ACLs were implemented The Red Hat Enterprise Linux 4 kernel provides ACL support for the ext3 file system and NFS exported file systems ACLs are also recognized on ext3 file systems accessed via Samba Along with support in the kernel the acl package is required to implement ACLs It contains the utilities used to add modify remove and retrieve ACL information The cp and mv commands copy or move any ACLs associated with files and directories 14 1 Mounting File Systems Before using ACLs for a file or directory the partition for the file or directory must be mounted with ACL support If it is a local ext3 file system it can mounted with the following command mount t ext3 o acl lt device name gt lt partition gt For example mount t ext3 o acl dev VolGroup00 LogVol02 work Alternatively if the partition is listed in the etc fstab file the entry for the partition can include the acl option LABEL work work ext3 acl t2 If an ext3 file system is accessed via Samba and ACLs have been enabled for it the ACLs are rec ognized because Samba has been compiled with the with acl support option No special flags are required when accessing or mounting a Samba share 14 1 1 NFS By default if the file system being exported by an NFS server supp
92. which package groups to install There are also options available to resolve and ignore package dependencies automatically Currently Kickstart Configurator does not allow you to select individual packages To install in dividual packages modify the spackages section of the kickstart file after you save it Refer to Section 1 5 Package Selection for details 40 2 10 Pre Installation Script Chapter 2 Kickstart Configurator Eile Help Basic Configuration Installation Method Boot Loader Options Partition Information Network Configuration Authentication Firewall Configuration Display Configuration Package Selection Pretnstallation Script Post4nstallation Script Pre Installation Script Warning An error in this script might cause your kickstart installation to fail Do not include the pre command at the beginning C Use an interpreter Type your pre script below Figure 2 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 To include a pre installation script type it in the text area To specify a scripting language to use to execute the script select the Use an interpreter option and enter the interpreter in the text box beside it For example usr bin python2 2 can be specified for
93. 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 18 Chapter 1 Kickstart Installations 1 4 1 Advanced Partitioning Example The following is a single integrated example showing the clearpart raid part volgroup and logvol kickstart options in action clearpart drives hda hdc initlabel Raid 1 IDE config part raid 11 size 1000 asprimary ondrive hda part raid 12 size 1000 asprimary ondrive hda part raid 13 size 2000 asprimary ondrive hda part raid 14 size 8000 ondrive hda part raid 15 size grow ondrive hda part raid 21 size 1000 asprimary ondrive hdc part raid 22 size 1000 asprimary ondrive hdc part raid 23 size 2000 asprimary ondrive hdc part raid 24 size 8000 ondrive hdc part raid 25 size grow ondrive hdc You can add spares x raid fstype ext3 device md0 level RAID1 raid 11 raid 21 raid safe fstype ext3 device md1 level RAID1 raid 12 raid 22 raid swap fstype swap device md2 level RAID1 raid 13 raid 23 raid usr fstype ext3 device md3 level RAID1 raid 14 raid 24 raid pv 01 fstype ext3
94. yy Inactive pppO Provider xDSL Figure 18 9 xDSL Device Be sure to select File gt Save to save the changes After adding the xDSL connection you can edit its configuration by selecting the device from the device list and clicking Edit For example when the device is added it is configured not to start at boot time by default Edit its configuration to modify this setting When the device is added it is not activated immediately as seen by its Inactive status To activate the device select it from the device list and click the Activate button If the system is configured to activate the device when the computer starts the default this step does not have to be performed again 18 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 o H 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 New button on the toolbar 3 Select Token Ring connection from the Device Type list and click Forward 4 If you have already added the token ring card to the hardware list select it from the Tokenring card list Otherwise select
95. 0 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 24 3 Group Declaration To configure a DHCP server that leases a dynamic IP address to a system within a subnet modify Example 24 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 190 Chapter 24 Dynamic Host Configuration Protocol DHCP 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 24 4 Range Parameter To assign an IP address to a client based on the MAC address of the network interface card use the hardware ethernet parameter within a host declaration As demonstrated in Example 24 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 Note that the optional parameter host name can also be used to assign a
96. 00 LogVol00 12G 6 0G 4 6G 57 dev sdal 99M 9 1M 85M 10 boot none 316M 0 316M 0 dev shm In the list of mounted 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 is displayed in a list The grand total for the current directory and subdirectories are also shown as the last line in the list If 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 GNOME System Monitor tab as shown in Figure 40 2 on the bottom of the tab under Devices Chapter 40 Gathering System Information 305 40 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 Applications the main menu on the panel gt System Tools gt Hardware Browser or type hwbrowser at a shell prompt As shown in Figure 40 3 it displays your CD ROM devices diskette drives hard drives and their partitions network devices pointing d
97. 0O for the connection and select whether the connection should be automatically activated when the computer starts Click Forward Select Network to Network encryption VPN and click Forward Select the type of encryption to use manual or automatic If manual is selected an encryption key must be provided later in the process If automatic is selected the racoon daemon is used to manage the encryption key If racoon is used the ipsec tools package must be installed Click Forward to continue On the Local Network page enter the following information Local Network Address The IP address of the device on the IPsec router connected to the private network Local Subnet Mask The subnet mask of the local network IP address Local Network Gateway The gateway for the private subnet Click Forward to continue IPsec Local Network Please enter your local network settings Local Network Address 192 168 1 3 Local Subnet Mask 255 255 255 0 Local Network Gateway 172 31 1 1 3 Cancel lt Back gt Eorward Figure 18 21 Local Network Information On the Remote Network page enter the following information Remote IP Address The publicly addressable IP address of the IPsec router for the other private network In our example for ipsecO enter the publicly addressable IP address of ipsecl and vice versa Remote Network Address The network addr
98. 2 Network File System NFS Chapter 23 Samba Samba uses the SMB protocol to share files and printers across a network connection Operating systems that support this protocol include Microsoft Windows OS 2 and Linux The Red Hat Enterprise Linux 4 kernel contains Access Control List ACL support for ext3 file systems If the Samba server shares an ext3 file system with ACLs enabled for it and the kernel on the client system contains support for reading ACLs from ext3 file systems the client automatically recognizes and uses the ACLs 23 1 Why Use Samba Samba is useful if you have a network of both Windows and Linux machines Samba allows files and printers to be shared by all the systems in a network To share files between Linux machines only use NFS as discussed in Chapter 22 Network File System NFS To share printers between Linux ma chines only you do not need to use Samba refer to Chapter 34 Printer Configuration 23 2 Configuring a Samba Server The default configuration file etc samba smb conf allows users to view their home directories as a Samba share It also shares all printers configured for the system as Samba shared printers In other words you can attach a printer to the system and print to it from the Windows machines on your network 23 2 1 Graphical Configuration To configure Samba using a graphical interface use the Samba Server Configuration Tool For command line configuration skip to Section 23
99. 204LC 1 i Free be installed 8678 MB If you do not know how to partition your system or if you need help with using the New Edit Dace Reset RAJD LM manual partitioning tools refer 7 Mount Point Size to the product documentation Device RAID Volume Pe Format p Start End i dana Hard Drives p AS fdevisda partitioning you can either accept the current partition Free Free space 8679 11107 settings click Next or modify Y dev sdb the setup using the manual Free Free space 8679 11107 partitioning tool Ifyou are manually partitioning your system you can see your current hard drive s and ns displayed below Use Hide RAID device LVM Volume Group members p B elease Notes ck gt t Figure 10 1 Two Blank Drives Ready For Configuration 1 In Disk Druid choose RAID to enter the software RAID creation screen 2 Choose Create a software RAID partition to create a RAID partition as shown in Figure 10 2 Note that no other RAID options such as entering a mount point are available until RAID partitions as well as RAID devices are created RAID Options Software RAID allows you to combine several disks into a larger RAID device A RAID device can be configured to provide additional speed and reliability compared to using an individual drive For more information on using RAID devices please consult the Red H
100. 3 After the Setup Agent has been completed Enter the following command from the command line as the root user e usr bin up2date register 5 Using the Mouse Red Hat Enterprise Linux is designed to use a three button mouse If you have a two button mouse you should have selected three button emulation during the installation process If you are using three button emulation pressing both mouse buttons at the same time equates to pressing the missing third middle button In this document if you are instructed to click with the mouse on something that means click the left mouse button If you need to use the middle or right mouse button that will be explicitly stated This will be reversed if you have configured your mouse to be used by a left handed person The phrase drag and drop may be familiar to you If you are instructed to drag and drop an item on your GUI desktop click on something and hold the mouse button down While continuing to hold down the mouse button drag the item by moving the mouse to a new location When you have reached the desired location release the mouse button to drop the item 6 Copying and Pasting Text With X Copying and pasting text is easy using your mouse and the X Window System To copy text click and drag your mouse over the text to highlight it To paste the text somewhere click the middle mouse button in the spot where the text should be placed 7 More to Come The Red Hat Enterpri
101. 7 Manually Upgrading the Kernel 0 0 cece ccc eee eese cece cacseesecececeeseeesensesesseeesaeseneeeee 285 37 1 Overview Of Kernel Packages inrsin dennen a e 285 37 2 Preparing to Upgrade 286 37 3 Downloading the Upgraded Kernel o 0 ce cc ceeeeceseeseseecseeeeeeeeseeesesseeeesaeaes 287 37 4 Performing the Upptade iscsi catsscz ccssttveastsevastie a NATET E 288 37 5 Verifying the Initial RAM Disk Image w 288 37 6 Verifying the Boot Loader 289 293 293 a295 295 38 Kernel Modules 38 1 Kernel Module Utilities 38 2 Persistent Module Loading 38 3 Additional Resources 00 39 Mail Transport Agent MTA Configuration 297 VI System Monitoring 299 40 Gathering System Information cece cece ceeceeecseseeeceessscseeenstesseseseeeesaeaesaeaee 301 40 1 System Processes 0 asceceseensssvensdeecenesssueds cecdedenvagureventenevnonsontbecndshensoveuvevenecseds 301 40 2 Memory USa gece issnin EEEE E EO E arenes dates 303 40 3 File Systems 40 4 Hardware 40 5 Additional RESOUICES ccscesssssssccsscsssssessccsssecssesssssessesscsnesscestenesenssnesneees 305 41 OProfile sirsiran aiian 41 1 Overview of Tools 41 2 Configuring OProfile 308 41 3 Starting and Stopping OProfile 312 41 4 Saving Data eee 312 4125 Analyzing the Data oraes isi raai O EE IE 312 41 6 Understanding dev oprof iLe onreyipe
102. 73 subscription registration v swap space 85 creating 85 expanding 85 explanation of 85 file creating 86 88 LVM2 creating 86 extending 86 reducing 87 removing 87 moving 88 recommended size 85 removing 87 syslogd 281 system analysis OProfile see OProfile system information file systems 304 330 dev shm 304 gathering 301 hardware 305 memory usage 303 processes 301 currently running 301 system recovery 53 common problems 53 forgetting the root password 53 hardware software problems 53 reinstalling the boot loader 56 unable to boot into Red Hat Enterprise Linux 53 system config authentication see Authentication Configuration Tool system config date see Time and Date Properties Tool system config display see X Configuration Tool system config httpd see HTTP Configuration Tool system config keyboard 239 system config kickstart see Kickstart Configurator system config mouse see Mouse Configuration Tool system config netboot 43 system config network see network configuration system config network cmd 131 145 151 system config packages see Package Management Tool system config printer see printer configuration system config securitylevel see Security Level Configuration Tool system config time see Time and Date Properties Tool system config users see user configuration and group configuration system logviewer see Log Viewer system switch mail see Mail Tran
103. 8 resembles the default configuration except for the use of RAID a New Edit Delete Reset RAID LVM Disk Setup Ana Device RAID Naine Type Format an Start End Choose where you would like SSE Red Hat Enterprise Linux AS to be installed dev md0 boot ext3 v 101 944 dev md1 swap v 1027 6 If you do not know how to dev md2 I ext3 vo 7546 16 partition your system or if you Y Hard Drives need help with using the devisda Psp pier ec aa dev sdal dev md0 software RAID 102 1 B dev sda2 dev md1 software RAID 1028 14 14 If you used automatic dev sda3 dev md2 software RAID 7546 145 1106 partitioning you can either Y jdev sdb accept the current partition dev sdb dev md0 software RAID 12 1 B settings click Next or modify jdev sdb2 dev mdi software RAID 1028 14 14 the setup using the manual dev sdb3 dev md2 software RAID 7546 145 1106 partitioning tool If you are manually partitioning your system you can see your current hard drive s and partitions displayed below Use C Hide RAID device LVM Volume Group members Buide Help GRelease Notes lt Back B gt Next Figure 10 8 Final Sample RAID Configuration The figure as shown in Figure 10 9 is an example of a RAID and LVM configuration Chapter 10 Software RAID Configuration 83 gt
104. 9 User Data Account Info Password Info Groups User Name tfox Full Name Tammy Fox Password Confirm Password Home Directory home tfox Login Shell bin bash 3 Cancel 2 OK Figure 33 3 User Properties The User Properties window is divided into multiple tabbed pages User Data Shows the basic user information configured when you added the user Use this tab to change the user s full name password home directory or login shell Account Info Select Enable account expiration if you want the account to expire on a certain date Enter the date in the provided fields Select User account is locked to lock the user account so that the user cannot log in to the system Password Info This tab shows the date that the user s password last changed To force the user to change passwords after a certain number of days select Enable password expiration The number of days before the user s password expires the number of days before the user is warned to change passwords and days before the account becomes inactive can also be changed Groups Select the groups that you want the user to be a member of and the user s primary group 33 3 Adding a New Group To add a new user group click the Add Group button A window similar to Figure 33 4 appears Type the name of the new group to create To specify a group ID for the new group selec
105. Any networked IPP printer found via CUPS browsing appears in the main window under the Browsed queues category If you have a firewall configured on the print server it must be able to send and receive connections on the incoming UDP port 631 If you have a firewall configured on the client the computer sending the print request it must be allowed to send and accept connections on port 631 260 Chapter 34 Printer Configuration If you disable the automatic browsing feature you can still add a networked IPP printer by clicking the New button in the main Printer Configuration Tool window to display the window in Figure 34 2 Click Forward to proceed In the window shown in Figure 34 3 enter a unique name for the printer in the Name text field The printer name cannot contain spaces and must begin with a letter The printer name may contain letters numbers dashes and underscores _ Optionally enter a short description for the printer which can contain spaces After clicking Forward Figure 34 5 appears Select Networked CUPS IPP from the Select a queue type menu Select a queue type Networked CUPS IPP z Server Path servername example com printers queuel is Help Cancel gq Back p gt Eorward Figure 34 5 Adding an IPP Printer Text fields for the following options appear Server The hostname or IP address of the remote machine to which the printer i
106. Authorization Required default Forbidden default Not Found default Method Not Allowed default Not Acceptable default Ie Error Code 400 Bad Request Default Error Page Footer Show footer with email address T Help Cancel 2 OK Figure 25 3 Site Configuration 198 Chapter 25 Apache HTTP Server Configuration The entries listed in the Directory Page Search List define the DirectoryIndex directive The DirectoryIndex is the default page served by the server when a user requests an index of a directory by specifying a forward slash at the end of the directory name For example when a user requests the page http www example com this_directory they are going to get either the DirectoryIndex page if it exists or a server generated directory list The server tries to find one of the files listed in the DirectoryIndex directive and returns the first one it finds If it does not find any of these files and if Options Indexes is set for that directory the server generates and returns a list in HTML format of the subdirectories and files in the directory Use the Error Code section to configure Apache HTTP Server to redirect the client to a local or external URL in the event of a problem or error This option corresponds to the ErrorDocument directive If a problem or error occurs when a client tries to connect to the Apache HTTP Server the default action is to display the short error message shown in the Erro
107. Bug Fix Alerts and Enhancement Alerts collectively known as Errata Alerts can be downloaded directly from Red Hat using the Red Hat Update Agent standalone application or through the RHN website available at https rhn redhat com File Edit View Go Bookmarks Tools Help EJ Red Hat Network Your RHN E reo mar nervon inaani S ma rm a 4x on No sysreus setecren manage Gear Your rin Tota systems g Mo recent actons Ot of date systems 2 Ungrouped systems 8 Inactive systems 6 View All Updated xpe package ives security issue Updated less package fixes securty issue Updated ts packages fix security vulnerabilities Updated kenel packages fix security vulnerabilities pitied nity package fixes terial of service issue Girt E EEEE SN A E 2 Updated mozilla packages fix a buffer overflow Oe a eevee 2 Updated xpat packages tix security issues 2 UW S 10 6 219 relevant erata stoun WewAbRecranens Figure 17 1 Your RHN Red Hat Network saves you time because you receive email when updated packages are released You do not have to search the Web for updated packages or security alerts By default Red Hat Network installs the packages as well You do not have to learn how to use RPM or worry about resolving software package dependencies RHN does it all Red Hat Network features include Errata Alerts learn when Security Alerts Bug Fix Alerts
108. Chapter 13 Implementing Disk Quotas gt Note The following examples assume that a separate home partition was created during the installation of Red Hat Enterprise Linux Although not ideal the root partition the installation default created partition can be used for setting quota policies in the etc fstab file 13 1 2 Remounting the File Systems After adding the usrquota and or grpquota options remount each file system whose fstab entry has been modified If the file system is not in use by any process use one of the following methods Issue the umount command followed by the mount command to remount the file system e Issue the mount o remount home command to remount the file system If the file system is currently in use the easiest method for remounting the file system is to reboot the system 13 1 3 Creating the Quota Database Files After each quota enabled file system is remounted the system is capable of working with disk quo tas However the file system itself is not yet ready to support quotas The next step is to run the quotacheck command The quotacheck command examines quota enabled file systems and builds a table of the current disk usage per file system The table is then used to update the operating system s copy of disk usage In addition the file system s disk quota files are updated To create the quota files aquota user and aquota group on the file system use the c option of the quotac
109. ES sesi essare dea esei Eie ET EREE AREY 175 23 1 Why Use Sambar rs eritreo EE RERA REA AAACN 177 23 2 Configuring Samba Server iseer sireenin r oeeaaeaii ae 177 23 3 Connecting to a Samba Share 183 23 4 Additional Resources 0 185 24 Dynamic Host Configuration Protocol DHCP 187 24 1 Why Use DHCP n se 187 24 2 Configuring a DHCP Server 187 24 3 Configuring a DHCP Client cc cecceccesessescseescseeseneeseeseseeseseeaeeaeaeeeseeeaeeeeaes 192 244 Additional RESOULCES ninasi esya na oia Ai aE 193 25 Apache HTTP Server Configuration 25 1 Basic Setn Sni eaae aA EA NEO AR RIA EEEE AIEEE TARRI 195 23 2 Default Settings i rne a A NAN A N 197 25 3 Virtual Hosts Settings 202 25 4 Server Settings 205 25 5 Performance Tuning 25 6 Saving Your Settings 25 7 Additional Resources 208 26 Apache HTTP Secure Server Configuration 211 26 1 Introduiction enninu nn e ees 211 26 2 An Overview of Security Related Packages 0 c cc ccceceesescsesseeeecseseeseeeeees 211 26 3 An Overview of Certificates and Security occ eeeeeeeeeereeeeeeeeneees 213 26 4 Using Pre Existing Keys and Certificates 0 ccccscsseeseseeseeeeteeeeeeeeeeeeseeeeaeees 214 26 5 Lypes of Certificates ieres aean ENEE E ERE EEA E 214 26 6 Generating a Key s s sssessssssssissesierereererssrsessree 215 26 7 Generating a Certificate Request to Send to a CA 217 26 8 Creating a Self
110. Enter key After typing all the commands press Enter to go to a blank line and type Ctrl D Alternatively a shell script can be entered at the prompt pressing Enter after each line in the script and typing Ctrl D on a blank line to exit If a script is entered the shell used is the shell set in the user s SHELL environment the user s login shell or bin sh whichever is found first As soon as the load average is below 0 8 the set of commands or script is executed If the set of commands or script tries to display information to standard out the output is emailed to the user Use the command atq to view pending jobs Refer to Section 35 2 3 Viewing Pending Jobs for more information Usage of the batch command can be restricted For more information refer to Section 35 2 5 Controlling Access to At and Batch for details 35 2 3 Viewing Pending Jobs To view pending at and batch jobs use the atq command The atq command displays a list of pending jobs with each job on a line Each line follows the job number date hour job class and username format Users can only view their own jobs If the root user executes the atq command all jobs for all users are displayed 35 2 4 Additional Command Line Options Additional command line options for at and batch include Option Description o f Read the commands or shell script from a file instead of specifying them at the prompt Send email to the user when the j
111. Ethernet Select the Ethernet device on the host to use to mount the diskless environment If the host only has one Ethernet card select eth0 Ignore the Kickstart File option It is only used for PXE installations Hostname or IP Address Subnet 192 168 1 1 Operating System thel 4as 2 C Serial Console Diskless OS Network OS Install Snapshot name test1 Kickstart File Ethemet etho z 3 Cancel 2 OK Figure 4 1 Add Diskless Host In the existing snapshot directory in the diskless directory a subdirectory is created with the Snapshot name specified as the file name Then all of the files listed in snapshot files and snapshot files customare copied copy from the root directory to this new directory 4 6 Booting the Hosts Consult the documentation for your PXE card to configure the host to boot via PXE When the diskless client boots it mounts the remote root directory in the diskless directory as read only It also mounts its individual snapshot directory as read write Then it mounts all the files and directories in the files and files custom files using the mount o bind over the read only 52 Chapter 4 Diskless Environments diskless directory to allow applications to write to the root directory of the diskless environment if they need to Chapter 5 Basic System Recovery When things go wrong there are ways to fix problems However these methods require that you understand the system well This chapt
112. HTTP Secure Server Configuration 217 Problems associated with not using a passphrase 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 webpages that appear to be from your secure server If UNIX security practices are rigorously maintained on the host computer all operating system patches and updates are installed as soon as they are available no unnecessary or risky services are operating and so on secure server s passphrase may seem unnecessary However since your secure server should not need to be re booted very often the extra security provided by entering a passphrase is a worthwhile effort in most cases The server key file should be owned by the root user on your system and should not be accessible to any other user Make a backup copy of this file and keep the backup copy in a safe secure place You need the backup copy because if you ever lose the server key file after using it to create your certificate request your certificate no longer works and the CA is not able to help you Your only option is to request and pay for a new certificate If you are going to purchase a certificate from a CA continue to Section 26 7 Generating a Certificate Request to Send toa CA If you are generating your own
113. M HOWTO from the Linux Documentation Project Chapter 8 LVM Configuration LVM can be configured during the graphical installation process the text based installation process or during a kickstart installation You can use the utilities from the 1vm package to create your own LVM configuration post installation but these instructions focus on using Disk Druid during installation to complete this task Read Chapter 7 Logical Volume Manager LVM first to learn about LVM An overview of the steps required to configure LVM include Creating physical volumes from the hard drives Creating volume groups from the physical volumes Creating logical volumes from the volume groups and assign the logical volumes mount points gt Note Although the following steps are illustrated during a GUI installation the same can be done during a text based installation Two 9 1 GB SCSI drives dev sda and dev sdb are used in the following examples They de tail how to create a simple configuration using a single LVM volume group with associated logical volumes during installation 8 1 Automatic Partitioning On the Disk Partitioning Setup screen select Automatically partition For Red Hat Enterprise Linux LVM is the default method for disk partitioning If you do not wish to have LVM implemented or if you require RAID partitioning manual disk partitioning through Disk Druid is required The following properties make up the automatical
114. 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 25 7 2 Useful Websites http www apache org The Apache Software Foundation http httpd apache org docs 2 0 The Apache Software Foundation s documentation on Apache HTTP Server version 2 0 including the Apache HTTP Server Version 2 0 User s Guide http www redhat com support resources web_ftp apache html Red Hat Support maintains a list of useful Apache HTTP Server links http www redhat com support docs faqs RH apache FAQ book1 html The Apache Centralized Knowledgebase compiled by Red Hat 25 7 3 Related Books Apache The Definitive Guide by Ben Laurie and Peter Laurie O Reilly amp Associates Inc Red Hat Enterprise Linux Reference Guide Red Hat Inc This companion manual includes instructions for migrating from Apache HTTP Server version 1 3 to Apache HTTP Server version Chapter 25 Apache HTTP Server Configuration 209 2 0 manually more details about the Apache HTTP Server directives and instructions for adding modules to the Apache HTTP Server 210 Chapter 25 Apache HTTP Server Configuration Chapter 26 Apache HTTP Secure Server Configuration 26 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
115. NFS HTIP FIP gt D 0 s client example com L lt net location gt k lt kernel gt K lt kickstart gt lt os identifer gt Chapter 3 PXE Network Installations 45 The following list explains the options e a Specifies that an OS instance is being added to the PXE configuration e i lt description gt Replace lt description gt with a description of the OS instance This corresponds to the Description field in Figure 3 1 p lt NFSIHTTPIFTP gt Specify which of the NFS FTP or HTTP protocols to use for installa tion Only one may be specified This corresponds to the Select protocol for installation menu in Figure 3 1 e D lt O0I1 gt Specify 0 which indicates that it is not a diskless configuration since pxeos can be used to configure a diskless environment as well e s client example com Provide the name of the NFS FTP or HTTP server after the s option This corresponds to the Server field in Figure 3 1 e L lt net location gt W Provide the location of the installation tree on that server after the L option This corresponds to the Location field in Figure 3 1 e k lt kernel gt Provide the specific kernel version of the server installation tree for booting e K lt kickstart gt Provide the location of the kickstart file if available e lt os identifer gt Specify the OS identifier which is used as the directory name in the tftpboot linux install directory This corr
116. P Click Forward 8 On the IP Settings page select whether to obtain an IP address automatically or whether to set on statically Click Forward when finished 9 On the Create Dialup Connection page click Apply After configuring the modem device it appears in the device list with the type Modem as shown in Figure 18 7 File Profile Help SfHB F x New Edit Copy Delete Activate Deactivate Devices Hardware IPsec DNS Hosts guc You may configure network devices associated with 3 o physical hardware here Multiple logical devices can be T associated with a single piece of hardware Profile Status Device Nickname Type Ve eae Modem Figure 18 7 Modem Device Be sure to select File gt Save to save the changes After adding the modem device you can edit its configuration by selecting the device from the device list and clicking Edit For example when the device is added it is configured not to start at boot time by default Edit its configuration to modify this setting Compression PPP options login name password and more can also be changed When the device is added it is not activated immediately as seen by its Inactive status To activate the device select it from the device list and click the Activate button If the system is configured to activate the device when the computer starts the default this step does not have to be performed again
117. Page Size allows the paper size to be selected The options include US Letter US Legal A3 and A4 Effective Filter Locale defaults to C If Japanese characters are being printed select ja_JP Oth erwise accept the default of C Media Source defaults to Printer default Change this option to use paper from a different tray To modify the driver options click OK to return to the main window Click Apply to save the change and restart the printer daemon 34 10 Saving the Configuration File When the printer configuration is saved using the Printer Configuration Tool the application creates its own configuration file that is used to create the files in the etc cups directory You can use the command line options to save or restore the Printer Configuration Tool file If the etc cups directory is saved and restored to the same locations the printer configuration is not restored because each time the printer daemon is restarted it creates a new etc printcap file from the Printer Configuration Tool configuration file When creating a backup of the system s configuration files use the following method to save the printer configuration files To save your printer configuration type this command as root usr sbin system config printer tui Xexport gt settings xml Your configuration is saved to the file settings xml If this file is saved it can be used to restore the printer settings This is useful if the printer configura
118. Red Hat Enterprise Linux 4 System Administration Guide 3 redhat Red Hat Enterprise Linux 4 System Administration Guide Copyright 2005 Red Hat Inc 3 Red Hat Inc 1801 Varsity Drive Raleigh NC 27606 2072 USA Phone 1 919 754 3700 Phone 888 733 4281 Fax 1 919 754 3701 PO Box 13588 Research Triangle Park NC 27709 USA rhel sag EN 4 Print RHI 2005 06 06T17 10U1 Copyright 2005 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 and the Red Hat Shadow Man logo are registered trademarks of Red Hat Inc in the United States and other countries All other trademarks referenced herein 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 Tt OTELI K HLH i PANET IE T E T E i 1 Changes To This Mangaleneir gern T AE e EEE ET R R i 2 Architecture specific Information ii 3 Docu
119. Resources s5s3seesc ss sasnvesyseesst stacvdsserastses ss sas TEEVEE ESTEE e EN R EE 102 14 Access Control Lists ireanii tein nn R EER AE o EN EA 2enmecate 103 14 1 Mounting File Systems 14 2 Setting Access ACLs 14 3 Setting Default ACLs 14 4 Retrieving ACLs 14 5 Archiving File Systems With ACLs 14 6 Compatibility with Older Systems 14 7 Additional Resources 106 III Package Management 15 Package Management with RPM uu cece eee cee cseeeeeeecaeseeeeecseseseeeeeseeseeseeesaeseeaeaes 111 15 1 RPM Design Goals ssr tn urerat tA SREY 111 15 2 USin RPM earn E RENEA NE AE ORR AN IEY 15 3 Checking a Package s Signature 15 4 Impressing Your Friends with RPM wu esse cseseeeesescseseeeeeteeseseseeeees 118 15 5 Additional Resources esiin tessstvsssessegsigtvesscsiatseatesayiseisssssgigavevsrsgesesteaeesss 120 16 Package Management Tool 16 1 Installing Packages 16 2 Removing Packages 17 Red Hat Network tesisi oiriin e KEEA ER ER IV Network Related Configurration ssscssssssssssssssssesssssssssssesessesssesssessssesesssessesesssesesseresees 129 18 Network Configuration 18 1 Overview 0 eee eects eeeeeee 18 2 Establishing an Ethernet Connection 18 3 Establishing an ISDN Connection 18 4 Establishing a Modem Connection a 135 18 5 Establishing an xDSL Connection 136 18 6 Establishing a Token Ring Connection oo ieee ese eeeeeeescs
120. S see NFS findsmb 184 firewall configuration see Security Level Configuration Tool floppy group use of 234 free 303 ftp 163 G getfacl 105 GNOME Print Manager 270 change printer settings 270 GNOME System Monitor 302 gnome system monitor 302 GnuPG checking RPM package signatures 117 group configuration adding groups 249 additional information 254 filtering list of groups 247 groupadd 251 modify groups for a user 248 modify users in groups 250 modifying group properties 250 viewing list of groups 247 groups see group configuration floppy use of 234 H hardware viewing 305 Hardware Browser 305 Hardware RAID see RAID hesiod 224 HTTP Configuration Tool directives see HTTP directives error log 198 modules 195 transfer log 198 323 HTTP directives DirectoryIndex 197 ErrorDocument 198 ErrorLog 199 Group 206 HostnameLookups 199 KeepAlive 207 KeepAliveTimeout 207 Listen 196 LogFormat 199 LogLevel 199 MaxClients 207 MaxKeepAliveRequests 207 Options 198 ServerAdmin 196 ServerName 196 TimeOut 207 TransferLog 199 User 206 httpd 195 hwbrowser 305 information about your system 301 insmod 294 installation kickstart see kickstart installations LVM 65 PXE see PXE installations software RAID 77 Internet connection see network configuration introduction i IPsec host to host 147 network to network 148 ipsec tools 147 149 iptables
121. Signed Certificate oe 218 26 9 Testing The Certificate wo 219 26 10 Accessing The Server we 220 26 1 1 Additional RESOULCES 325s sssses peteccescaesphonceccts cones aaa PEE EVESEN 220 21 Authentication Confido i orai rE E ER EER E 223 27 1 User Information 223 27 2 Authentication 224 27 3 Command Line Version 226 V System Configuration 229 28 Console ACCESS a aa iaaa E E AE AE E A ARE A i 231 28 1 Disabling Shutdown Via Ctrl Alt Del 231 28 2 Disabling Console Program Access 231 28 3 Defining the Console eee 232 28 4 Making Files Accessible From the Console 232 28 5 Enabling Console Access for Other Applications 233 28 6 The floppy Group 234 29 Date and Time Configuration 235 29 1 Time and Date Properties 235 29 2 Network Time Protocol NTP Properties cccccecsseeseseeteeeeteeeeeeeeeeeeseeeeaeees 236 29 3 Time Zone Configuration 236 30 Keyboard Configuration tics iusvse iin ina nies sensors neh R ii ia 239 3 1 Mouse Configuration ieorcccncsssccscuavetesssnsmioteteciutive gusta lecle avy e a 241 32 X Window System Configuration 243 243 wee 243 244 32 1 Display Settings 32 2 Display Hardware Settings 32 3 Dual Head Display Settings 33 User and Group Configuration 247 33 1 Adding a New User 247 33 2 Modifying User Properties mirassi si in ia E ORR E 248 33 3 Addin
122. Table of Contents 28 29 30 31 32 33 34 35 36 37 38 39 Console ACCESS tenes reee e eeta e EST a Seea TEO E e REES Date and Time Configuration scssssssssssssssssessessssssssesesssesseessesesesseessessssassessesesesseseseseses Keyboard Configuration scsssssccsssssssscsssssssesssesssssssesessesssessoesescesossoessesesssesessecesosssseeseses Mouse Configuration sccsssssssscssesesssesessssssessoesessssesesessesesssesesssssesesssessesssesessesesssesseeseses X Window System Configuration User and Group Configuration c sssscsssssssssscssssssssssssesesssssseessesesssssessessssesesssesesesseseseseses Printer Configuration cssssssscessssssesscesssssesseesessssesesessesssssesesescesosessecsessssessesessseseeeseses Automated Tasks sssssssssscsssssssecsssssessesssssssesesessesssessssssesesessesssssesessasssesssessasesesesessassseseseses MEO 8 1 C E E A E SE E sovvesdeouschatornesdsonsisensdonscbasedsenetbiduoetessiotsccesedsens Manually Upgrading the Kernel eessesseseseososseroscoseeresosroseoresseseecososresessesrereseoseseerrsreseeeesesres Kernel Modules scssssssssssssssssssssssescsvesssesesssessesssesssvesesssescesssesesossasssesssecsssssesesessesssesesesoases Mail Transport Agent MTA Configuration s sssssssssssessssesseessssesssssessessssssesssesesssevese 297 Chapter 28 Console Access When normal non root users log into a computer
123. Test that the logical volume has been extended properly cat proc swaps free 11 2 2 Creating an LVM2 Logical Volume for Swap To add a swap volume group assuming dev VolGroup00 LogVol02is the swap volume you want to add Create the LVM2 logical volume of size 256 MB lvm lvcreate VolGroup00 n LogVol02 L 256M 2 Format the new swap space mkswap dev VolGroup00 LogVol02 3 Add the following entry to the etc fstab file dev VolGroup00 LogVol02 swap swap defaults 00 4 Enable the extended logical volume swapon va 5 Test that the logical volume has been extended properly cat proc swaps free 11 2 3 Creating a Swap File To add a swap file 1 Determine the size of the new swap file in megabytes and multiply by 1024 to determine the number of blocks 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 Chapter 11 Swap Space 87 4 To enable the swap file immediately but not automatically at boot time swapon swapfile 5 To enable it at boot time edit etc fstab to include the following entry swapfile swap swap defaults 00 The next time the system boots it enables the new swap file 6 After adding the new swap file and enabling it verify it is enabled by viewing t
124. The combination of these three components are referred to in this chapter as the secure Web server or just as the secure server The mod_ss1 module is a security module for the Apache HTTP Server The mod_ss1 module uses the tools provided by the OpenSSL Project to add a very important feature to the Apache HTTP Server the ability to encrypt communications In contrast regular HTTP communications between a browser and a Web server are sent in plain text which could be intercepted and read by someone along the route between the browser and the server This chapter is not meant to be complete and exclusive documentation for any of these programs When possible this guide points to appropriate places where you can find more in depth documenta tion on particular subjects This chapter shows you how to install these programs You can also learn the steps necessary to generate a private key and a certificate request how to generate your own self signed certificate and how to install a certificate to use with your secure server The mod_ss1 configuration file is located at etc 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 the etc httpd conf httpd conf file This statement is included by default in the default Apache HTTP Server configuration file 26 2 An Overview of Security Related Packages To enable the secure server you must have the following pack
125. This method is useful if you want to add a printer from a script or in the post section of a kickstart installation 34 11 1 Adding a Local Printer To add a printer system config printer tui Xadd local options Options device node Required The device node to use For example dev 1p0 make make Required The IEEE 1284 MANUFACTURER string or if none is available the printer manu facturer s name as it appears in the foomatic database model mode 1 Required The IEEE 1284 MODEL string or if non is available the printer model listed in the foomatic database name name Optional The name to be given to the new queue If one is not given a name based on the device node such as Ip0 is used as default Optional Set this as the default queue After adding the printer use the following command to start restart the printer daemon service cups restart 34 11 2 Removing a Local Printer A printer queue can also be removed via the command line As root to remove a printer queue system config printer tui Xremove local options Options device node Required The device node used such as dev 1p0 make make Required The IEEE 1284 MANUFACTURER string or if none is available the printer man ufacturer s name as it appears in the foomatic database 270 Chapter 34 Printer Configuration model mode1 Required The IEEE 1284 MODEL string or if none is available the printer mod
126. _TRANS_P BUS_TRANS_IO BUS_TRANS_DEF BUS_TRAN_BURST BUS_TRAN_ANY BUS_TRAN_MEM BUS_DATA_RCV BUS_BNR_DRV BUS_HIT_DRV BUS_HITM_DRV BUS_SNOOP_STALL COMP_FLOP_RET FLOPS iCYCLES_DIV_BUSY LD_BLOCKS SB_DRAINS MISALIGN_MEM_REF EMON_KNI_PREF_DISPATCHED EMON KNI PRFF MISS self generated transactions K any transactions bus cycles this processor is driving HIT pin Profiler running O hours 59 mins 29 interrupts second total 49471 Flush profiler data Stop profiler Save and quit Figure 41 1 OProfile Setup On the right side of the tab select the Profile kernel option to count events in kernel mode for the currently selected event as discussed in Section 41 2 3 Separating Kernel and User space Profiles If this option is unselected no samples are collected for the kernel Select the Profile user binaries option to count events in user mode for the currently selected event as discussed in Section 41 2 3 Separating Kernel and User space Profiles If this option is unselected no samples are collected for user applications Use the Count text field to set the sampling rate for the currently selected event as discussed in Section 41 2 2 1 Sampling Rate If any unit masks are available for the currently selected event as discussed in Section 41 2 2 2 Unit Masks they are displayed in the Unit Masks area on the right side
127. able and the fourth column is the symbol name To sort the output from the largest number of samples to the smallest reverse order use r in conjunction with the 1 option i lt symbol name gt List sample data specific to a symbol name For example the following output is from the command opreport l i __gconv_transform_utf 8_internal lib tls libc lt version gt so samples symbol name 12 100 000 gconv_transform_utf8_internal The first line is a summary for the symbol executable combination The first column is the number of samples for the memory symbol The second column is the percentage of samples for the memory address relative to the total number of samples for the symbol The third column is the symbol name Chapter 41 OProfile 315 List sample data by symbols with more detail than 1 For example the following output is from the command opreport l1 d __gconv_transform_utf8_internal lib tls libc lt version gt so vma samples symbol name 00a98640 12 100 000 _ _gconv_transform_utf8_internal 00a98640 1 8 3333 00a9868c 2 16 6667 00a9869a 1 8 3333 00a986c1 1 8 3333 00a98720 1 8 3333 00a98749 1 8 3333 00a98753 1 8 3333 00a98789 1 8 3333 00a98864 1 8 3333 00a98869 1 8 3333 00a98b08 1 8 3333 The data is the same as the 1 option except that for each symbol each virtual memory ad dress used is shown For each virtual memory address the number of samples and percentage of samples relative
128. access from all hosts Allow hosts from 192 168 1 0 255 255 255 0 Let htaccess files override directory options Directory var www html testing T Help 4 OK 3 Cancel Figure 25 7 Directory Settings If you check the Let htaccess files override directory options the configuration directives in the htaccess file take precedence Chapter 25 Apache HTTP Server Configuration 203 25 3 Virtual Hosts Settings Virtual hosts allow you to run different servers for different IP addresses different host names or dif ferent ports on the same machine For example you can run the website for http www example com and http www anotherexample com on the same Web server using virtual hosts This option cor responds 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 The HTTP Configuration Tool includes a default virtual host as shown in Figure 25 8 Main Virtual Hosts Server Performance Tuning
129. ages installed at a minimum httpd The httpd package contains the httpd daemon and related utilities configuration files icons Apache HTTP Server modules man pages and other files used by the Apache HTTP Server mod_ssl The mod_ss1 package includes the mod_ss1 module which provides strong cryptography for the Apache HTTP Server via the Secure Sockets Layer SSL and Transport Layer Security TLS protocols openssl The openss1 package contains the OpenSSL toolkit The OpenSSL toolkit implements the SSL and TLS protocols and also includes a general purpose cryptography library Additionally other software packages provide certain security functionalities but are not required by the secure server to function 212 Chapter 26 Apache HTTP Secure Server Configuration httpd devel The httpd devel package contains the Apache HTTP Server include files header files and the APXS utility You need all of these if you intend to load any extra modules other than the modules provided with this product Refer to the Red Hat Enterprise Linux Reference Guide for more information on loading modules onto your secure server using Apache s dynamic shared object DSO functionality If you do not intend to load other modules onto your Apache HTTP Server you do not need to install this package OpenSSH packages The OpenSSH packages provide the OpenSSH set of network connectivity tools for logging into and executing commands on a remot
130. alHost directive 25 3 1 2 SSL Note You cannot use name based virtual hosts with SSL because the SSL handshake when the browser accepts the secure Web server s certificate occurs before the HTTP request which identifies the appropriate name based virtual host If you plan to use name based virtual hosts remember that they only work with your non secure Web server Chapter 25 Apache HTTP Server Configuration 205 General Options Page Options SSL Logging Environment Performance Enable SSL support SSL Configuration Certificate File fetc httpd conf ssl crt server crt Certificate Key File etc httpd conf ssl key server key Certificate Chain File fetc httpd conf ssl crt ca crt E Certificate Authority File etc httpd conf ssl crt ca bundle crt sst Options O FakeBasicAuth C ExportCertData CompatEnvVars C StrictRequire C OptRenegotiate E Help 3 Cancel 2 OK Figure 25 9 SSL Support 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
131. ame eg city Newbury Raleigh Organization Name eg company My Company Ltd Test Company Organizational Unit Name eg section Testing 218 Chapter 26 Apache HTTP Secure Server Configuration 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 is to be used shown like the following Country Name 2 letter code GB The default input in brackets is GB Accept the default by pressing Enter or fill in your country s two letter code You have to type in the rest of the values All of these should be self explanatory but you must follow these guidelines e Do not abbreviate the locality or state Write them out for example St Louis should be written out as Saint Louis e If you are sending this CSR to a CA be very careful to provide correct information for all of the fields but especially for the Organization Name and the Common Name CAs check the information provided in the CSR to determine whether your organization is responsible for what you provided as the Common Name CAs rejects CSRs which include information they perceive as invalid
132. ame to expand the list From the expanded list select a printer If the printer you are looking for does not appear in the list click the Specify button on the right Text fields for the following options appear Workgroup The name of the Samba workgroup for the shared printer Server The name of the server sharing the printer Share The name of the shared printer on which you want to print This name must be the same name defined as the Samba printer on the remote Windows machine User name The name of the user you must log in as to access the printer This user must exist on the Windows system and the user must have permission to access the printer The default user name is typically guest for Windows servers or nobody for Samba servers Password The password if required for the user specified in the User name field Click Forward to continue The Printer Configuration Tool then attempts to connect to the shared printer If the shared printer requires a username and password a dialog window appears prompting you to provide a valid username and password for the shared printer If an incorrect share name is specified you can change it here as well If a workgroup name is required to connect to the share it can be specified in this dialog box This dialog window is the same as the one shown when the Specify button is clicked Next select the printer type Refer to Section 34 7 Selecting the Printer Model an
133. an be allocated to LVM partitions The first step in creating a successful LVM implementation is the creation of the physical volume s 1 Select New 2 Select physical volume LVM from the File System Type pulldown menu as shown in Figure 8 5 Chapter 8 LVM Configuration 69 Add Partition Mount Point Not Applicable v File System Type physical volume LVM sda 8676 MB IBM PSG ST39103LC Allowable Drives 1 sdb 8676 MB IBM PSG ST39204LC Size MB 100 Additional Size Options O Fixed size O Fill all space up to MB 1 Fill to maximum allowable size C Force to be a primary partition R Cancel 2 oK Figure 8 5 Creating a Physical Volume 3 You cannot enter a mount point yet you can once you have created all your physical volumes and then all volume groups 4 A physical volume must be constrained to one drive For Allowable Drives select the drive on which the physical volume are created If you have multiple drives all drives are selected and you must deselect all but one drive 5 Enter the size that you want the physical volume to be 6 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 s
134. ange this value to a directory writable by the user the server runs as if you want to write the core dumps to disk for debugging purposes 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 are also 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 waming Unless you know exactly what you are doing do not set the user directive to root Using root as the User creates 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 Chapter 25 Apache HTTP Server Configuration 207 The Group value corresponds to the Group directive The Group directive is similar to the Use
135. ansport Agent Switcher 297 starting in text mode 297 Mail User Agent 297 Master Boot Record 53 reinstalling 56 MDS passwords 225 memory usage 303 mkfs 92 mkpart 91 modem connection see network configuration modprobe 294 modprobe conf 293 monitor settings for dual head 244 settings for X 244 mounting NFS file systems 169 mouse how to use vi MTA setting default 297 switching with Mail Transport Agent Switcher 297 MUA 297 N neat see network configuration Network Administration Tool see network configuration Network Booting Tool 43 pxeboot 46 pxeos 44 using with diskless environments 50 using with PXE installations 43 network configuration device aliases 145 DHCP 132 Ethernet connection 132 activating 133 IPsec host to host 147 IPsec network to network 148 ISDN connection 134 activating 134 logical network devices 143 managing etc hosts 142 managing DNS Settings 141 managing hosts 142 modem connection 135 activating 136 overview 132 326 PPPoE connection 136 profiles 143 activating 144 restoring from file 151 saving to file 151 static IP 132 token ring connection 138 activating 139 wireless connection 140 activating 141 xDSL connection 136 activating 138 Network Device Control 144 Network File System see NFS Network Time Protocol see NTP NFS etc fstab 169 additional resources 175 autofs see autofs command line configuration 173 con
136. any of these advanced installation tasks Table of Contents 1 Kickstart Installations 2 Kickstart Configurator 3 PXE Network Installations 4 Diskless Environments 5 Basic System Recovery Chapter 1 Kickstart Installations 1 1 What are Kickstart Installations Many system administrators would prefer to use an automated installation method to install Red Hat Enterprise Linux on their machines To answer this need Red Hat created the kickstart installation method Using kickstart a system administrator can create a single file containing the answers to all the questions that would normally be asked during a typical installation Kickstart files can be kept on a single server system and read by individual computers during the installation This installation method can support the use of a single kickstart file to install Red Hat Enterprise Linux on multiple machines making it ideal for network and system administrators Kickstart provides a way for users to automate a Red Hat Enterprise Linux installation 1 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 media with the kickstart file or make the kickstart file available on the network 3 Make the installation tree available 4 Start the kickstart installation This chapter e
137. apter 12 Managing Disk Storage 95 pvdata Display the on disk metadata for physical volume s pvdisplay pvmove pvremove pvresize PVs pvscan segtypes vgcfgbackup vgcfgrestore vgchange vgck vgconvert vgcreate vgdisplay vgexport vgextend vgimport vgmerge vgmknodes vgreduce vgremove vgrename vgs vgscan version Table 12 2 Lvm commands Display various attributes of physical volume s Move extents from one physical volume to another Remove LVM label s from physical volume s Display various attributes of physical volumes Remove LVM labels from physical volumets group Create a volume group Create a volume group Create the special files for volume group devices in dev Remove a physical volume from a volume group Display software and driver version information Move physical volumes into a new volume group Display software and driver version information 96 Chapter 12 Managing Disk Storage Chapter 13 Implementing Disk Quotas Disk space can be restricted by implementing disk quotas which alert a system administrator is alerted before a user consumes too much disk space or a partition becomes full Disk quotas can be configured for individual users as well as user groups This kind of flexibility makes it possible to give each user a small quota to handle personal files such as email and reports while allowing the projects they work on to have mor
138. are DNS Hosts gu Oo You may configure network devices associated with 3 oo physical hardware here Multiple logical devices can be d associated with a single piece of hardware Profile Status Device Nickname Type amp Active etho etho Ethernet amp Active ethO ethO_office Ethernet Active ethO ethO_home eme Active Profile Home modified Figure 18 17 Home Profile You can also configure eth0 to activate in the Office profile only and to activate a PPP modem device in the Home profile only Another example is to have the Common profile activate eth0 and an Away profile activate a PPP device for use while traveling To activate a profile at boot time modify the boot loader configuration file to include the netprofile lt profilename gt option For example if the system uses GRUB as the boot loader and boot grub grub conf contains title Red Hat Enterprise Linux 2 6 9 5 EL root hd0 0 kernel vmlinuz 2 6 9 5 EL ro root dev VolGroup00 LogVol00 rhgb quiet initrd initrd 2 6 9 5 EL img modify it to the following where lt profilename gt is the name of the profile to be activated at boot time title Red Hat Enterprise Linux 2 6 9 5 EL Chapter 18 Network Configuration 145 root hd0 0 kernel vmlinuz 2 6 9 5 EL ro root dev VolGroup00 LogVol00 netprofile lt profilename gt rhgb quiet initrd initrd 2 6 9 5 EL img To switch pr
139. arily have to start from scratch to get it to compile You can look at the patch to see what you might need to do All the compiled in defaults and all of the changes that were made to get the software to build properly are easily visible using this technique The goal of keeping sources pristine may only seem important for developers but it results in higher quality software for end users too 15 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 refer to Section 15 5 Additional Resources for more information on RPM 15 2 1 Finding RPM Packages Before using an RPM you must know where to find them An Internet search returns many RPM repositories but if you are looking for RPM packages built by Red Hat they can be found at the following locations The Red Hat Enterprise Linux CD ROMs The Red Hat Errata Page available at http www redhat com apps support errata A Red Hat FTP Mirror Site available at http www redhat com download mirror html Red Hat Network Refer to Chapter 17 Red Hat Network for more details on Red Hat Network 15 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 1386 To install a
140. art to Start or restart the service 20 6 Additional Resources For more information refer to the following resources 20 6 1 Installed Documentation The man pages for ntsysv chkconfig xinetd and xinetd conf man 5 hosts_access The man page for the format of host access control files in section 5 of the man pages 162 Chapter 20 Controlling Access to Services 20 6 2 Useful Websites http Awww xinetd org The xinetd webpage It contains a more detailed list of features and sample configuration files 20 6 3 Related Books Red Hat Enterprise Linux Reference Guide Red Hat Inc This companion manual contains detailed information about how TCP wrappers and xinetd allow or deny access as well as how to configure network access using them It also provides instructions for creating iptables firewall tules Red Hat Enterprise Linux Security Guide Red Hat Inc This manual discusses securing services with TCP wrappers and xinetd such as logging denied connection attempts Chapter 21 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 21 1 Why Use OpenSSH If you use OpenSSH tools you are enhancing th
141. at Enterprise Linux AS documentation You currently have 0 software RAID partition s free to use To use RAID you must first create at least two partitions of type software RAID Then you can create a RAID device which can be formatted and mounted What do you want to do now Create a software RAID partition O Create a RAID device default dev md0 O Clone a driv o create a RAID device default 3 Cancel 2 OK Figure 10 2 RAID Partition Options 3 A software RAID partition must be constrained to one drive For Allowable Drives select the drive on which RAID is to be created If you have multiple drives all drives are selected and you must deselect all but one drive Chapter 10 Software RAID Configuration 79 Add Partition Mount Point Not Applicabl x File System Type software RAID y sda 8676 MB IBM PSG ST39103LC Allowable Drives 1 sdb 8676 MB IBM PSG ST39204LC Size MB 100 P3 Additional Size Options Fixed size O Fill all space up to MB 1 z Fill to maximum allowable size Force to be a primary partition were ee Figure 10 3 Adding a RAID Partition 4 Enter the size that you want the partition to be 5 Select Fixed size to make the partition the specified size select Fill all space up to MB and enter a size in MBs to give range for the partition size or select Fill to maximum allowable size to make
142. at can be intercepted This corresponds to the encrypted passwords option Refer to Section 23 2 3 Encrypted Passwords for more information about en crypted Samba passwords Guest Account When users or guest users log into a Samba server they must be mapped to a valid user on the server Select one of the existing usernames on the system to be the guest Samba account When guests log in to the Samba server they have the same privileges as this user This corresponds to the guest account option After clicking OK the changes are written to the configuration file and the daemon is restart thus the changes take effect immediately 23 2 1 2 Managing Samba Users The Samba Server Configuration Tool requires that an existing user account be active on the system acting as the Samba server before a Samba user can be added The Samba user is associated with the existing user account 180 Chapter 23 Samba tfox Add User bfox Edit User Delete User Figure 23 4 Managing Samba Users To add a Samba user select Preferences gt Samba Users from the pulldown menu and click the Add User button In the Create New Samba User window select a Unix Username from the list of existing users on the local system If the user has a different username on a Windows machine and needs to log into the Samba server from the Windows machine specify that Windows username in the Windows Username field The Aut
143. ates are issued for a particular IP address and domain name pair You must get a new certificate if you are changing your IP address or domain name If you have a certificate from VeriSign and you are changing your server software VeriSign is a widely used CA If you already have a VeriSign certificate for another purpose you may have been considering using your existing VeriSign certificate with your new secure server However you are not be allowed to because VeriSign issues certificates for one specific server software and IP address domain name combination If you change either of those parameters for example if you previously used a different secure server product the VeriSign certificate you obtained to use with the previous configuration will not work with the new configuration You must obtain a new certificate If you have an existing key and certificate that you can use you do not have to generate a new key and obtain a new certificate However you may need to move and rename the files which contain your key and certificate Move your existing key file to etc httpd conf ssl key server key Move your existing certificate file to etc httpd conf ssl crt server crt After you have moved your key and certificate skip to Section 26 9 Testing The Certificate If you are upgrading from the Red Hat Secure Web Server your old key htt psd key and certificate httpsd crt are located in etc httpd conf Move and rename your
144. ath gt The installation program uses DHCP to configure the Ethernet card For example if your HTTP server is server example com and the kickstart file is in the HTTP directory mydir ks cfg the correct boot command would be ks http server example com mydir ks cfg ks floppy The installation program looks for the file ks cfg on a vfat or ext2 file system on the diskette in dev fdo Chapter 1 Kickstart Installations 25 ks floppy lt path gt The installation program looks for the kickstart file on the diskette in dev fdo as file lt path gt ks hd lt device gt lt file gt The installation program mounts the file system on lt device gt which must be vfat or ext2 and look for the kickstart configuration file as lt file gt in that file system for example ks hd sda3 mydir ks cfg ks file lt file gt The installation program tries to read the file lt file gt from the file system no mounts are done This is normally used if the kickstart file is already on the initrd image ks cdrom lt path gt The installation program looks for the kickstart file on CD ROM as file lt path gt KS If ks is used alone the installation program configures the Ethernet card to use DHCP The kickstart file is read from the bootServer from the DHCP response as if it is an NFS server sharing the kickstart file By default the bootServer is the same as the DHCP server The name of the kickstart file is one of the following
145. based event by default If more than one counter exists on the processor the counters other than counter 0 are not set to an event by default The default events monitored are shown in Table 41 3 Default Event for Counter 310 Chapter 41 OProfile Default Event for Counter Pentium Pro Pentium CPU_CLK_UNHALTED The processor s clock is not halted II Pentium II Athlon AMD64 Pentium 4 HT and GLOBAL_POWER_EVENTS The time during which the processor is non aie ae a Itanium 2 CPU cpULCYCLES sd CPU jerucyels Table 41 3 Default Events The number of events that can be monitored at one time is determined by the number of counters for the processor However it is not a one to one correlation on some processors certain events must be mapped to specific counters To determine the number of counters available execute the following command cat dev oprofile cpu_type The events available vary depending on the processor type To determine the events available for profiling execute the following command as root the list is specific to the system s processor type op_help The events for each counter can be configured via the command line or with a graphical interface For more information on the graphical interface refer to Section 41 8 Graphical Interface If the counter cannot be set to a specific event an error message is displayed To set the event for each configurable counter via the command line us
146. bin modprobe e100 loads any module dependencies and then the e100 module To print to the screen all commands as sbin modprobe executes them use the v option For example sbin modprobe v e100 Output similar to the following is displayed sbin insmod lib modules 2 6 9 5 EL kernel drivers net e100 ko Using lib modules 2 6 9 5 EL kernel drivers net el00 ko Symbol version prefix smp_ The sbin insmod command also exists to load kernel modules however it does not resolve de pendencies Thus it is recommended that the sbin modprobe command be used To unload kernel modules use the sbin rmmod command followed by the module name The rmmod utility only unloads modules that are not in use and that are not a dependency of other modules in use For example the command Chapter 38 Kernel Modules 295 sbin rmmod e100 unloads the e100 kernel module Another useful kernel module utility is modinfo Use the command sbin modinfo to display information about a kernel module The general syntax is sbin modinfo options lt module gt Options include d which displays a brief description of the module and p which lists the pa rameters the module supports For a complete list of options refer to the modinfo man page man modinfo 38 2 Persistent Module Loading Kernel modules are usually loaded directly by the facility that requires them which is given correct settings in the etc modprobe conf file However
147. by typing the following command at a shell prompt lt rpm file gt with file name of the RPM package rpm K nosignature lt rpm file gt The message lt rpm file gt md5 OK is displayed This brief message means that the file was not corrupted by the download To see a more verbose message replace K with Kvv in the command On the other hand how trustworthy is the developer who created the package If the package is signed with the developer s GnuPG key you know that the developer really is who they say they are 118 Chapter 15 Package Management with RPM 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 installation GnuPG is installed by default That way you can immediately start using GnuPG to verify any packages that you receive from Red Hat First you must import Red Hat s public key 15 3 1 Importing Keys To verify Red Hat packages you must import the Red Hat GPG key To do so execute the following command at a shell prompt rpm import usr share rhn RPM GPG KEY To display a list of all keys in
148. cally Connection Timeout defines how long your server waits to receive a GET request how long it waits to receive TCP packets on a POST or PUT request and how long it waits 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 MaxRequestsPerChild directive If you check the Allow unlimited requests per connection option the MaxkKeepAliveRequests directive is set 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 waits 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 the server to slow down depending on how many users are trying to connect to it The higher the number the more server processes are waiting for another conne
149. ccount Provider Name T Online Account Setup Enter the login name for this account Login Name Enter the password for this account Password 3 Cancel lt Back D Forward Figure 18 8 xDSL Settings 5 If the Select Ethernet Adapter window appears select the manufacturer and model of the Ethernet card Select the device name If this is the system s first Ethernet card select eth0 as the device name if this is the second Ethernet card select eth1 and so on The Network Administration Tool also allows you to configure the resources for the NIC Click Forward to continue 6 Enter the Provider Name Login Name and Password If you have a T Online account instead of entering a Login Name and Password in the default window click the T Online Account Setup button and enter the required information Click Forward to continue 7 On the Create DSL Connection page click Apply After configuring the DSL connection it appears in the device list as shown in Figure 18 7 138 Chapter 18 Network Configuration Eile Profile Help Hrer BB x New Edit Copy Delete Activate Deactivate Devices Hardware IPsec DNS Hosts You may configure network devices associated with 3 physical hardware here Multiple logical devices can be T associated with a single piece of hardware Profile Status Device Nickname type
150. ces with different nicknames and different configuration options all to be specifically associated with eth0 Logical network devices are different from device aliases Logical network devices associated with the same physical device must exist in different profiles and cannot be activated simultaneously Device aliases are also associated with the same physical hardware device but device aliases associated with the same physical hardware can be activated at the same time Refer to Section 18 11 Device Aliases for details about creating device aliases Profiles can be used to create multiple configuration sets for different networks A configuration set can include logical devices as well as hosts and DNS settings After configuring the profiles you can use the Network Administration Tool to switch back and forth between them By default there is one profile called Common To create a new profile select Profile gt New from the pull down menu and enter a unique name for the profile You are now modifying the new profile as indicated by the status bar at the bottom of the main window Click on an existing device already in the list and click the Copy button to copy the existing device to a logical network device If you use the New button a network alias is created which is incorrect To change the properties of the logical device select it from the list and click Edit For example the nickname can be changed to a more descriptive name su
151. cess the system To minimize this threat it is recommended that the administrator verifies that the user is ready to log in when the account is unlocked In either case upon initial log in the user is prompted for a new password 33 6 Explaining the Process The following steps illustrate what happens if the command useradd juan is issued on a system that has shadow passwords enabled 1 A new line for juan is created in etc passwd The line has the following characteristics It begins with the username juan There is an x for the password field indicating that the system is using shadow passwords A UID at or above 500 is created Under Red Hat Enterprise Linux UIDs and GIDs below 500 are reserved for system use A GID at or above 500 is created The optional GECOS information is left blank The home directory for juan is set to home juan 254 Chapter 33 User and Group Configuration The default shell is set to bin bash 2 A new line for juan is created in etc shadow The line has the following characteristics It begins with the username juan Two exclamation points appear in the password field of the etc shadow file which locks the account Note If an encrypted password is passed using the p flag it is placed in the etc shadow file on the new line for the user The password is set to never expire 3 A new line for a group named juan is created in etc group A group with
152. ch as ethO_office so that it can be recognized more easily In the list of devices there is a column of checkboxes labeled Profile For each profile you can check or uncheck devices Only the checked devices are included for the currently selected profile For example if you create a logical device named ethO_office in a profile called Office and want to activate the logical device if the profile is selected uncheck the etno device and check the eth0_office device For example Figure 18 16 shows a profile called Office with the logical device eth0_office It is configured to activate the first Ethernet card using DHCP 144 File Profile Help Br B F x New Edit Copy Delete Activate Deactivate Devices Hardware DNS Hosts z A You may configure network devices associated with 3 oo physical hardware here Multiple logical devices can be associated with a single piece of hardware Profile Status Device Nickname Type amp Active E etho etho Ethernet Active etho eth0_o eme Active ethO eth0_home Ethernet Active Profile Office modified Figure 18 16 Office Profile Chapter 18 Network Configuration Notice that the Home profile as shown in Figure 18 17 activates the ethO_home logical device which is associated with etho File Profile Help Br B Fr xX New Edit Copy Delete Activate Deactivate Devices Hardw
153. ch packages need to be updated on your machine including the kernel This chapter is only useful for those individuals that require manual updating of kernel packages without using the up2date command A waming Please note that building a custom kernel is not supported by the Red Hat Global Services Support team and therefore is not explored in this manual Qr Use of up2date is highly recommended by Red Hat for installing upgraded kernels For more information on Red Hat Network the Red Hat Update Agent and up2date refer to Chapter 17 Red Hat Network 37 1 Overview of Kernel Packages Red Hat Enterprise Linux contains the following kernel packages some may not apply to your archi tecture kernel Contains the kernel and the following key features Uniprocessor support for x86 and Athlon systems can be run on a multi processor system but only one processor is utilized Multi processor support for all other architectures For x86 systems only the first 4 GB of RAM is used use the kerne1 hugemem package for x86 systems with over 4 GB of RAM kernel devel Contains the kernel headers and makefiles sufficient to build modules against the kernel package kernel hugemem only for i686 systems In addition to the options enabled for the kernel package the key configuration options are as follows Support for more than 4 GB of RAM up to 64 GB for x86 286 Chapter 37 Manually Upgrading the Kern
154. ckages with a checkmark beside them are currently installed 122 Chapter 16 Package Management Tool 16 1 Installing Packages To install standard packages from a package group that is not currently installed check the checkbox beside that package group To customize the packages to be installed within a group click the Details link beside it The list of standard and extra packages is displayed as shown in Figure 16 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 clicking the Details link 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 2 V Extra Packages redhat config printer gui A GUI frontend for printconf Z XFree86 Xvfb A virtual framebuffer X Windows System server for XFree86 Z XFree86 Xnest A nested XFree86 server rhn applet Panel applet for indication that newer Red Hat packages are available Z gdm The GNOME Display Manager desktop backgrounds extra Desktop background images dhat config date A graphical interface for modifying system date and time term xterm
155. ckets on port 1234 through specify 1234 udp To specify multiple ports separate them by commas firstboot optional Determine whether the Setup Agent starts the first time the system is booted If enabled the firstboot package must be installed If not specified this option is disabled by default enable The Setup Agent is started the first time the system boots 8 Chapter 1 Kickstart Installations disable The Setup Agent is not started the first time the system boots reconfig Enable the Setup Agent to start at boot time in reconfiguration mode This mode enables the language mouse keyboard root password security level time zone and networking configuration options in addition to the default ones halt optional Halt the system after the installation has successfully completed This is similar to a manual installation where anaconda displays a message and waits for the user to press a key before re booting During a kickstart installation if no completion method is specified the reboot option is used as default The halt option is roughly equivalent to the shutdown h command For other completion methods refer to the poweroff reboot and shutdown kickstart options 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 cdrom harddrive nfs or url for
156. clicked To change the time use the up and down arrow buttons beside the Hour Minute and Second in the Time section Changes take place until after the OK button is clicked Clicking the OK button applies any changes made to the date and time the NTP daemon settings and the time zone settings It also exits the program 29 2 Network Time Protocol NTP Properties As shown in Figure 29 2 the second tabbed window that appears is for configuring NTP Date amp Time Network Time Protocol Time Zone Your computer can synchronize its clock with a remote time server using the Network Time Protocol J Enable Network Time Protocol NTP Servers Server clock redhat com v Add 0 pool ntp org Delete 1 pool ntp org 2 pool ntp org Kil V Hide advanced options V Use Local Time Source Enable NTP Broadcast B Heip Cancel 2 OK Figure 29 2 NTP Properties The Network Time Protocol NTP daemon synchronizes the system clock with a remote time server or time source such as a satellite The application allows you to configure an NTP daemon to syn chronize your system clock with a remote server To enable this feature select Enable Network Time Protocol This enables the Server pulldown menu You can choose one of the predefined servers or type a server name in the pulldown menu Your system does not start synchronizing with
157. cron service automatically at boot time 35 2 At and Batch While cron is used to schedule recurring tasks the at command is used to schedule a one time task at a specific time and 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 the at RPM package must be installed and the atd service must be running To determine if the package is installed use the rpm q at command To determine if the service is running use the command sbin service atd status 35 2 1 Configuring At Jobs To schedule a one time job at a specific time type the command at time where time is the time to execute the command The argument t ime can be one of the following HH MM format For example 04 00 specifies 4 00 a m If the time is already past it is executed at the specified time the next day midnight Specifies 12 00 a m noon Specifies 12 00 p m teatime Specifies 4 00 p m month name day year format For example January 15 2002 specifies the 15th day of January in the year 2002 The year is optional e MMDDYY MM DD YY or MM DD YY formats For example 011502 for the 15th day of January in the year 2002 now time time is in minutes hours days or weeks For example now 5 days specifies that the command should be executed at the same time five days from now The time must be specified first followed by the optiona
158. cted 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 clicking OK to add edit or delete an NFS share from the list the changes take place immedi ately the server daemon is restarted and the old configuration file is saved as etc exports bak The new configuration is written to etc exports The NFS Server Configuration Tool reads and writes directly to the etc exports configuration file Thus the file can be modified manually after using the tool and the to
159. ction from the last client that connected to it 208 Chapter 25 Apache HTTP Server Configuration 25 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 are prompted to confirm this decision If you click Yes to confirm this choice your settings are not 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 appears If you an swer Yes your settings are saved in etc httpd conf httpd conf Remember that your original configuration file is overwritten with your new settings If this is the first time that you have used the HTTP Configuration Tool a dialog window appears 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 saves the manually modified file as etc httpd conf httpd conf bak roren 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 25 7 Additional Resources To learn more about the Apache HTTP Server refer to the following resources 25 7 1 Installed Documentation e usr share docs httpd lt version gt migration html The Apache
160. cts if the X Window System is running If it is running the program starts in graphical mode as shown in Figure 39 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 system switch mail nox The Mail Transport Agent Switcher is a tool which enables users to easily switch between various Mail Transport Agent A that they have installed Please choose your Mail transport agent Available Mail Transport Agent Sendmail O Postfix O Exim Figure 39 1 Mail Transport Agent Switcher If you select OK to change the MTA the selected mail daemon is enabled to start at boot time and the unselected mail daemons are disabled so that they do not start at boot time The selected mail daemon is started and any other mail daemon is stopped thus making the changes take place immediately 298 Chapter 39 Mail Transport Agent MTA Configuration For more information about email protocols and MTAs refer to the Red Hat Enterprise Linux Refer ence Guide VI System Monitoring System administrators also monitor system performance Red Hat Enterprise Linux contains tools to assist administrators with these tasks Table of Contents 40 Gathering System Information csssssssscsesssssessssesssesseesssssessesssesssessssesesssessssensseseesesesers 301 41 OProfile EE E A E EE ETATE TEE A 307 Chapter 40 Gathering System Information Before you learn how t
161. d in the format YYYY MM DD Instead of the date the number of days since January 1 1970 can also be used W days Specify the number of days before the password expiration date to warn the user Table 33 3 chage Command Line Options Orio If the chage command is followed directly by a username with no options it displays the current password aging values and allows them to be changed If a system administrator wants a user to set a password the first time the user log in the user s initial or null password can be set to expire immediately forcing the user to change it immediately after logging in for the first time To force a user to configure a password the first time the user logs in at the console follow these steps Note this process does not work if the user logs in using the SSH protocol 1 Lock the user s password If the user does not exist use the useradd command to create the user account but do not give it a password so that it remains locked If the password is already enabled lock it with the command usermod L username 2 Force immediate password expiration Type the following command chage d 0 username This command sets the value for the date the password was last changed to the epoch January 1 1970 This value forces immediate password expiration no matter what password aging policy if any is in place Chapter 33 User and Group Configuration 253 3 Unlock the account Ther
162. d Finishing for de tails A waming If you require a username and password they are stored unencrypted in files only readable by root and Ipd Thus it is possible for others to learn the username and password if they have root access To avoid this the username and password to access the printer should be different from the username and password used for the user s account on the local Red Hat Enterprise Linux system If they are different then the only possible security compromise would be unauthorized use of the printer If there are file shares from the server it is recommended that they also use a different password than the one for the print queue Chapter 34 Printer Configuration 263 34 5 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 34 1 appears Click Forward to proceed In the window shown in Figure 34 3 enter a unique name for the printer in the Name text field The printer name cannot contain spaces and must begin with a letter The printer name may contain letters numbers dashes and underscores _ Optionally enter a short description for the printer which can contain spaces Select Networked Novell NCP from the Select a queue type menu Select a queue type Networked Novell NCP Server User servername example com username Queue Password queuename
163. dem 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 e xDSL token ring CIPE e wireless devices It can also be used to configure IPsec connections manage DNS settings and manage the etc hosts file used to store additional hostnames and IP address combinations To use the Network Administration Tool you must have root privileges To start the application go to the Main Menu Button on the Panel gt System Settings gt Network or type the command system config network at a shell prompt for example in an XTerm or a GNOME terminal If you type the command the graphical version is displayed if X is running otherwise the text based version is displayed To use the command line version execute the command system config network cmd help as root to view all of the options File Profile Help arf x New Edit Copy Delete Activate Deactivate Devices Hardware IPsec DNS Hosts You may configure network devices associated with 3 Bo physical hardware here Multiple logical devices can be T associated with a single piece of hardware Profile Status Device Nickname Type X active e e ene vV Active etho etho Ethernet Figure 18 1 Network Administration Tool If you prefer mod
164. device md4 level RAID1 raid 15 raid 25 LVM configuration so that we can resize var and usr local later volgroup sysvg pv 01 logvol var vgname sysvg size 8000 name var logvol var freespace vgname sysvg size 8000 name freespacetouse logvol usr local vgname sysvg size 1 grow name usrlocal This advanced example implements LVM over RAID as well as the ability to resize various directories for future growth 1 5 Package Selection Use the packages command to begin a kickstart file section that lists the packages you would like to install this is for installations only as package selection during upgrades is not supported Packages can be specified by group or by individual package name The installation program defines several groups that contain related packages Refer to the RedHat base comps xml file on the first Red Hat Enterprise Linux CD ROM for a list of groups Each group has an id user visibility value name description and package list In the package list the packages marked as mandatory are always installed if the group is selected the packages marked default are selected by default if the group is selected and the packages marked optional must be specifically selected even if the group is selected to be installed In most cases it is only necessary to list the desired groups and not individual packages Note that the Core and Base groups are always selected by default so it is not nec
165. directory that contains the RedHat directory For example if the HTTP server contains the directory mirrors redhat i386 RedHat enter mirrors redhat i386 for the HTTP directory Hard Drive Choose this option to install or upgrade from a hard drive Hard drive installations require the use of ISO or CD ROM images Be sure to verify that the ISO images are intact before you start the installation To verify them use an md5sum program as well as the linux mediacheck boot option as discussed in the Red Hat Enterprise Linux Installation Guide Enter 30 Chapter 2 Kickstart Configurator the hard drive partition that contains the ISO images for example dev hda1 in the Hard Drive Partition text box Enter the directory that contains the ISO images in the Hard Drive Directory text box 2 3 Boot Loader Options File Help Basic Configuration Boot Loader Options required Installation Method Install new boot loader Boot Loader Options O Do not install a boot loader Upgrade existing boot loader Partition Information z 9 Network Configuration GRUB Options Authentication Use GRUB password Firewall Configuration 2 Passwore Display Configuration Confirm Password Package Selection i Pre Installation Script Encrypt GRUB password Postnstallation Script install boot loader on Master Boot Record MBR O Install boot loader on first sector of the boot partition Kernel parameters
166. drive Red Hat Enterprise Linux can be both an NFS server and an NFS client which means that it can export file systems to other systems and mount file systems exported from other machines 22 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 myproject 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 22 2 Mounting NFS File Systems Use the mount command to mount a shared NFS directory from another machine mount shadowman example com misc export misc local waming The mount point directory on the local machine misc local in the above example must exist before this command can be executed In this command shadowman example comis the hostname of the NFS file server misc export is the directory that shadowman is exporting and misc local is the location to mount the file system on the local machine After the mount command runs and if the client has proper permis sions from the shadowman example com NFS server the client user can execute the command 1s misc local to display a listing of the files in
167. e Swap space in Linux is used when the amount of physical memory RAM is full If the system needs more memory resources and the RAM 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 should be equal to twice your computer s physical RAM for up to 2 GB of physical RAM For physical RAM above 2 GB the size of your swap should be equal to the amount of physical RAM above 2 GB The size of your swap should never less than 32 MB Using this basic formula a system with 2 GB of physical RAM would have 4 GB of swap while one with 3 GB of physical RAM would have 5 GB of swap f Note Unfortunately deciding on the amount of swap to allocate to Red Hat Enterprise Linux is more of an art than a science so hard rules are not possible Each system s most used applications should be accounted for when determining swap size EB EEEE File systems and LVM2 volumes assigned as swap space cannot be in use when being modified For example no system processes can be assigned the swap space as well as no amount of swap should be allocated and used by the kernel Use the free and cat p
168. e 5024 LogVol02 N A 1024 Delete Cancel 2 OK Figure 8 9 Pending Logical Volumes Click OK to apply the volume group and all associated logical volumes The following figure shows the final manual configuration Disk S New Edit Delete Reset RAID LVM IS etu p Device Moats Rany Type Format ele Start End RAID Volume MB Choose where you would like Red Hat Enterprise Linux AS to 7 LVM Volume Groups be installed Y VolGroup0o 17152 LogVol02 swap v 1024 If you do not know how to LogVol00 ext3 v 10016 partition your system or if you LogVol01 home ext3 4 5024 need help with using the ue Y Hard Drives manual partitioning tools refer to the product documentation woldevizea dev sdal boot ext3 v 102 1 i Ifyou used automatic dev sda2 VolGroup00 LVMPV 8574 14 1106 partitioning you can either V jdev sdb accept the current partition dev sdb1 VolGroup00 LVMPV 8676 1 1106 settings click Next or modify the setup using the manual partitioning tool If you are manually partitioning your system you can see your J current hard drive s and RE 2 partitions displayed below Use C Hide RAID device LVM Volume Group members Bhide Help B Release Notes lt Back B Next Figure 8 10 Final Manual Configuration Chapt
169. e 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 36 2 Viewing Log Files Most log files are in plain text format You can view them with any text editor such as vi or Emacs Some log files are readable by all users on the system however root privileges are required to read most log files To view system log files in an interactive real time application use the Log Viewer To start the application go to Applications the main menu on the panel gt System Tools gt System Logs or type the command system logviewer at a shell prompt The application only displays log files that exist thus the list might differ from the one shown in Figure 36 1 To filter the contents of the log file for keywords type the keyword s in the Filter for text field and click Filter Click Reset to reset the contents 282 FreeWnn libs 1 10p 020 5 i386 rpm_ GConf2 2 8 1 1 i386 rpm GConf2 devel 2 8 1 1 1386 rpm HelixPlayer 1 0 1 gold 8EL i386 rpm ImageMagick 6 0 7 1 5 i386 rpm ImageMagick c 6 0 7 1 5 i386 rpm X Org X11 Log ImageMagick devel 6 0 7 1 Filter for mageMagick
170. e are two common approaches to this step The administrator can assign an initial password or assign a null password warming Do not use the passwa command to set the password as it disables the immediate password expiration just configured To assign an initial password use the following steps Start the command line Python interpreter with the python command It displays the follow ing Python 2 2 2 1 Dec 10 2002 09 57 09 GCC 3 2 1 20021207 Red Hat Enterprise Linux 4 3 2 1 2 on linux2 Type help copyright credits or license for more information gt gt gt At the prompt type the following replacing password with the password to encrypt and salt with a combination of exactly 2 upper or lower case alphabetic characters digits the dot character or the slash character such as ab or 12 import crypt print crypt crypt password salt The output is the encrypted password similar to 12CsGd8FRcMSM Type Ctrl D to exit the Python interpreter Cut and paste the exact encrypted password output without a leading or trailing blank space into the following command usermod p encrypted password username Instead of assigning an initial password a null password can be assigned using the following command usermod p username Caution While using a null password is convenient for both the user and the administrator there is a slight risk that a third party can log in first and ac
171. e computer and watching the messages to ensure that the hardware is detected properly 37 6 2 Itanium Systems Itanium systems use ELILO as the boot loader which uses boot efi EFI redhat elilo conf as the configuration file Confirm that this file contains an image section with the same version as the kernel package just installed prompt timeout 50 default old image vmlinuz 2 6 9 5 EL label linux initrd initrd 2 6 9 5 EL img read only append root LABEL image vmlinuz 2 6 9 1 906_EL label old initrd initrd 2 6 9 1 906 img read only append root LABEL Notice that the default is not set to the new kernel To configure ELILO to boot the new kernel change the value of the default variable to the value of the label for the image section that contains the new kernel Begin testing the new kernel by rebooting the computer and watching the messages to ensure that the hardware is detected properly 37 6 3 IBM S 390 and IBM eServer zSeries Systems The IBM S 390 and IBM eServer zSeries systems use z IPL as the boot loader which uses etc zipl conf as the configuration file Confirm that the file contains a section with the same version as the kernel package just installed defaultboot default old target boot linux image boot vmlinuz 2 6 9 5 EL ramdisk boot initrd 2 6 9 5 EL img parameters root LABEL old image boot vmlinuz 2 6 9 1 906_EL ramdisk boot initrd 2 6 9 1 906_EL img parameters root LABEL
172. e default location is etc dhcpd conf e 1f lt filename gt Specify the location of the lease database file If a lease database file already exists it is very important that the same file be used every time the DHCP server is started It is strongly recommended that this option only be used for debugging purposes on non production machines The default location is var lib dhcp dhcpd leases 192 Chapter 24 Dynamic Host Configuration Protocol DHCP q Do not print the entire copyright message when starting the daemon 24 2 4 DHCP Relay Agent The DHCP Relay Agent dhcrelay allows for the relay of DHCP and BOOTP requests from a subnet with no DHCP server on it to one or more DHCP servers on other subnets When a DHCP client requests information the DHCP Relay Agent forwards the request to the list of DHCP servers specified when the DHCP Relay Agent is started When a DHCP server returns a reply the reply is broadcast or unicast on the network that sent the original request The DHCP Relay Agent listens for DHCP requests on all interfaces unless the interfaces are specified in etc sysconfig dhcrelay with the INTERFACES directive To start the DHCP Relay Agent use the command service dhcrelay start 24 3 Configuring a DHCP Client The first step for configuring a DHCP client is to make sure the kernel recognizes the network interface card Most cards are recognized during the installation process and the system is config
173. e default settings for these options are appropriate for most situations Main Virtual Hosts Server Performance Tuning Lock File varflock httpd lock Browse PID File var run httpd pid v Browse Core Dump Directory etc httpd v Browse User apache Group apache OK 3 Cancel T Heip Figure 25 10 Server Configuration The Lock File value corresponds to the LockFile directive This directive sets the path to the lockfile used when the server is compiled with either USE_FCNTL_SERIALIZED_ACCEPT or USE_FLOCK_SERIALIZED_ACCEPT It must be stored on the local disk It should be left to the default value unless the 1ogs 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 executing a core dump The default value is the ServerRoot However if the user that the server runs as can not write to this directory the core dump can not be written Ch
174. e 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 securely copying files between machines The openssh askpass package supports the display of a dialog window which prompts for a password during use of the OpenSSH agent The openssh askpass gnome package can be used in conjunction with the GNOME desktop environment to display a graphical dialog window when OpenSSH programs prompt for a pass word If you are running GNOME and using OpenSSH utilities you should install this package The openssh server package contains the sshd secure shell daemon and related files The secure shell daemon is the server side of the OpenSSH suite and must be installed on your host to allow SSH clients to connect to your host The openssh clients package contains the client programs needed to make encrypted con nections to SSH servers including the following ssh a secure replacement for rsh sftp a secure replacement for ftp for transferring files between machines and slogin a secure re placement for rlogin for remote login and telnet for communicating with another host via the Telnet protocol For more information
175. e opcontrol dump command To start OProfile from the graphical interface click Start profiler To stop the profiler click Stop profiler Exiting the application does not stop OProfile from sampling 41 9 Additional Resources This chapter only highlights OProfile and how to configure and use it To learn more refer to the following resources 41 9 1 Installed Docs usr share doc oprofile lt version gt oprofile html OProfile Manual oprofile man page Discusses opcontrol opreport opannotate and op_help Chapter 41 OProfile 319 41 9 2 Useful Websites http oprofile sourceforge net Contains the latest documentation mailing lists IRC channels and more 320 Chapter 41 OProfile Index Symbols dev oprofile 315 dev shm 304 etc auto master 170 etc cups 257 etc exports 173 etc fstab 60 169 etc fstab file enabling disk quotas with 97 etc hosts 142 etc httpd conf httpd conf 195 etc printcap 257 etc sysconfig dhcpd 191 proc directory 306 var spool cron 276 A Access Control Lists see ACLs ACLs access ACLs 103 additional resources 106 archiving with 105 default ACLs 105 getfacl 105 mounting file systems with 103 mounting NFS shares with 103 on ext3 file systems 103 retrieving 105 setfacl 104 setting access ACLs 103 with Samba 103 activating your subscription v adding group 251 user 250 Apache HTTP Server see HTTP Configuration To
176. e opcontrol opcontrol event lt event name gt lt sample rate gt Replace lt event name gt with the exact name of the event from op_help and replace lt sample rate gt with the number of events between samples 41 2 2 1 Sampling Rate By default a time based event set is selected It creates a sample every 100 000 clock cycles per processor If the timer interrupt is used the timer is set to whatever the jiffy rate is and is not user settable If the cpu_type is not timer each event can have a sampling rate set for it The sampling rate is the number of events between each sample snapshot When setting the event for the counter a sample rate can also be specified opcontrol event lt event name gt lt sample rate gt Replace lt sample rate gt with the number of events to wait before sampling again The smaller the count the more frequent the samples For events that do not happen frequently a lower count may be needed to capture the event instances Chapter 41 OProfile 311 QO caution Be extremely careful when setting sampling rates Sampling too frequently can overload the system causing the system to appear as if it is frozen or causing the system to actually freeze 41 2 2 2 Unit Masks If the cpu_type is not timer unit masks may also be required to further define the event Unit masks for each event are listed with the op_help command The values for each unit mask are listed in hexadecimal format To speci
177. e retrieved from Red Hat Network This src rpm must then be rebuilt locally using the rpmbuild command Refer to the latest distribution Release Notes including all updates at https www redhat com docs manuals enterprise for more information on obtaining and installing the kernel source package 37 2 Preparing to Upgrade Before upgrading the kernel take a few precautionary steps The first step is to make sure working boot media exists for the system in case a problem occurs If the boot loader is not configured properly to boot the new kernel the system cannot be booted into Red Hat Enterprise Linux without working boot media For example to create a boot diskette login as root and type the following command at a shell prompt sbin mkbootdisk uname r Chapter 37 Manually Upgrading the Kernel 287 Om Refer to the mkbootdisk man page for more options Creating bootable media via CD Rs CD RWs and USB flash drives are also supported given the system BIOS also supports it Reboot the machine with the boot media and verify that it works before continuing Hopefully the media is not needed but store it in a safe place just in case To determine which kernel packages are installed execute the following command at a shell prompt rpm qa grep kernel The output contains some or all of the following packages depending on the system s architecture the version numbers and packages may differ kernel 2 6 9 5 EL ke
178. e security of your machine All communications using OpenSSH tools including passwords are encrypted Telnet and ftp use plain text passwords and send all information unencrypted The information can be intercepted the passwords can be retrieved and your system could be compromised by an unauthorized person logging in to your system using one of the intercepted passwords The OpenSSH set of utilities should be used whenever possible to avoid these security problems Another reason to use OpenSSH is that it automatically forwards the DISPLAy variable to the client machine In other words if you are running the X Window System on your local machine and you log in to a remote machine using the ssh command when you run a program on the remote machine that requires X it will be displayed on your local machine This feature is convenient if you prefer graphical system administration tools but do not always have physical access to your server 21 2 Configuring an OpenSSH Server To run an OpenSSH server you must first make sure that you have the proper RPM packages installed The openssh server package is required and depends on the openssh package The OpenSSH daemon uses the configuration file etc ssh sshd_config The default configu ration file should be sufficient for most purposes If you want to configure the daemon in ways not provided by the default sshd_config read the sshd man page for a list of the keywords that can be defined in the c
179. e sizable quotas assuming the projects are given their own groups In addition quotas can be set not just to control the number of disk blocks consumed but to control the number of inodes data structures that contain information about files in UNIX file systems Because inodes are used to contain file related information this allows control over the number of files that can be created The quota RPM must be installed to implement disk quotas For more information on installing RPM packages refer to Part II Package Management 13 1 Configuring Disk Quotas To implement disk quotas use the following steps 1 Enable quotas per file system by modifying the etc fstab file 2 Remount the file system s 3 Create the quota database files and generate the disk usage table 4 Assign quota policies Each of these steps is discussed in detail in the following sections 13 1 1 Enabling Quotas As root using a text editor edit the etc fstab file Add the usrquota and or grpquota options to the file systems that require quotas dev VolGroup00 LogVol00 ext3 defaults t i LABEL boot boot ext3 defaults F2 none dev pts devpts gid 5 mode 620 0 0 none dev shm tmpfs defaults 00 none proc proc defaults 00 none sys sysfs defaults 00 dev VolGroup00 LogVol02 home ext3 defaults usrquota grpquota 1 2 dev VolGroup00 LogVol01 swap swap defaults 00 In this example the home file system has both user and group quotas enabled 98
180. e 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 following format minute hour day month dayofweek command minute any integer from 0 to 59 hour any integer from 0 to 23 276 Chapter 35 Automated Tasks day any integer from 1 to 31 must be a valid day if a month is specified month any integer from 1 to 12 or the short name of the month such as jan or feb dayofweek any integer from 0 to 7 where 0 or 7 represents Sunday or the short name of the week such as sun or mon command the command to execute the command can either be a command such as 1s proc gt gt tmp proc or the command to execute a custom script For any of the above values an asterisk can be used to specify all valid values For example an asterisk for the month value means execute the command every month within the constraints of the other values A hyphen between integers specifies a range of integers For example 1 4 means the integers 1 2 3 and 4 A list of values separated by commas specifies a list For example 3 4 6 8 indicates those four specific integers The forward slash can be used to specify step values The value of an integer can be skipped within a range by following the range with lt integer gt For example 0 59 2 can be used to define every other minute in the minute field Step values ca
181. eading a computer firewall attempts to prevent computer viruses from spreading to your computer and to prevent unauthorized users from accessing your computer A firewall exists between your computer and the network It determines which services on your computer remote users on the network can access A properly configured firewall can greatly increase the security of your system It is recommended that you configure a firewall for any Red Hat Enterprise Linux system with an Internet connection 19 1 Security Level Configuration Tool During the Firewall Configuration screen of the Red Hat Enterprise Linux installation you were given the option to enable a basic firewall as well as to allow specific devices incoming services and ports After installation you can change this preference by using the Security Level Configuration Tool To start the application select Main Menu Button on the Panel gt System Settings gt Security Level or type the command system config securitylevel from a shell prompt for example in an XTerm or a GNOME terminal Ore ele Please choose the security level for the system Firewall Options SELinux Security level Enable firewall v WWW HTTP FTP Trusted services L SSH L Telnet Mail SMTP C etho Trusted devices sit0 Other ports 1029 tcp Cancel 2 OK Figure 19 1 Security Level Configuration
182. eboot command refer to the pxeboot man page Chapter 3 PXE Network Installations 47 3 4 Starting the tftp Server On the DHCP server verify that the tftp server package is installed with the command rpm q tftp server If it is not installed install it via Red Hat Network or the Red Hat Enterprise Linux CD ROMs For more information on installing RPM packages refer to Part III Package Management tftp is an xinetd based service start it with the following commands sbin chkconfig level 345 xinetd on sbin chkconfig level 345 tftp on These commands configure the tftp and xinetd services to immediately turn on and also configure them to start at boot time in runlevels 3 4 and 5 3 5 Configuring the DHCP Server If a DHCP server does not already exist on the network configure one Refer to Chapter 24 Dynamic Host Configuration Protocol DHCP for details Make sure the configuration file contains the following so that PXE booting is enabled for systems which support it allow booting allow bootp class pxeclients match if substring option vendor class identifier 0 9 PXEClient next server lt server ip gt filename linux install pxelinux 0 where lt next server gt option should be replaced with the IP address of the tftp server 3 6 Adding a Custom Boot Message Optionally modify tftpboot linux install msgs boot msg to use a custom boot message 3 7 Performing the PXE Installatio
183. ecommended that you change this setting 4 Select which physical volumes to use for the volume group 8 2 4 Creating the LVM Logical Volumes Create logical volumes with mount points such as home and swap space Remember that boot cannot 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 8 8 appears Make Logical Volume Mount Point lt Not Applicable gt v File System Type swap es Logical Volume Name LogVol02 Size MB 1024 Max size is 2112 MB 8 Cancel 2 OK Figure 8 8 Creating a Logical Volume Repeat these steps for each volume group you want to create o You may want to leave some free space in the logical volume group so you can expand the logical volumes later The default automatic configuration does not do this but this manual configuration example does approximately 1 GB is left as free space for future expansion 72 Chapter 8 LVM Configuration Make LVM Volume Group Volume Group Name VolGroup00 Physical Extent 32 MB Z sda2 8512 00 MB Physical Volumes to Use I sdbl 8640 00 MB Used Space 16064 00 MB 93 7 Free Space 1088 00 MB 6 3 Total Space 17152 00 MB Logical Volumes Logical Volume Name Mount Point Size MB Add L 6 a5 ogVol00 1001 Edit LogVol01 hom
184. ed SMTP server can allow remote machines to use your server to send spam Chapter 19 Basic Firewall Configuration 155 19 1 3 Trusted Devices Selecting any of the Trusted devices allows access to your system for all traffic from that device it becomes 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 is allowed Selecting eth0 as trusted means all traffic over the Ethernet is allowed but the ppp interface is still firewalled To restrict traffic on an interface leave it unchecked You may have noticed a sit0 device in the Trusted devices section This device stands for simple internet transition which encapsulates IPv6 traffic into IPv4 traffic and then is tunneled For basic firewall rules this device can be ignored and left as an untrusted device EB wnportant It is not recommended that you make any device that is connected to public networks such as the Internet a Trusted device 19 1 4 Other Ports The Security Level Configuration Tool includes the Other ports section for adding custom IP ports to become trusted by iptables For example to allow NFS IRC and Internet printing protocol IPP to be allowed to pass through the firewall the following would be inserted in the Other ports section 2049 tcp 194 tcp 631 tcp 19 1 5 Saving the Settings Click OK to save the chang
185. ed entry To delete an entry select it and click the Delete button Ox If you set the server to listen to a port under 1024 you must be root to start it For port 1024 and above httpd can be started as a regular user Chapter 25 Apache HTTP Server Configuration 197 Listen to all addresses a Address 192 168 1 4 g Port 80 38 Cancel Figure 25 2 Available Addresses 25 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 A window as shown in Figure 25 3 appears 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 25 2 1 Site Configuration The default values for the Directory Page Search List and Error Pages work for most servers If you are unsure of these settings do not modify them Page Options Logging Environment Performance Directory Page Search List Add Pa Edit B Delete List of files to search for when a directory is requested Eg index html index shtml etc Error Pages Error Code Behavior Location P Edit Bad Request CEES
186. ed parity disk represents an inherent bottleneck level 4 is seldom used without accompanying technologies such as write back caching Although RAID level 4 is an option in some RAID partitioning schemes it is not an option allowed in Red Hat Enterprise Linux RAID installations The storage capacity of Hardware RAID level 4 is equal to the capacity of member disks minus the capacity of one member disk The storage capacity of Software RAID level 4 is equal to the capacity of the member partitions minus the size of one of the partitions if they are of equal size Level 5 This is the most common type of RAID By distributing parity across some or all of an array s member disk drives RAID level 5 eliminates the write bottleneck inherent in level 4 The only performance bottleneck is the parity calculation process With modern CPUs and Software RAID that usually is not a very big problem As with level 4 the result is asymmetrical perfor mance with reads substantially outperforming writes Level 5 is often used with write back caching to reduce the asymmetry The storage capacity of Hardware RAID level 5 is equal to the capacity of member disks minus the capacity of one member disk The storage capacity of Software RAID level 5 is equal to the capacity of the member partitions minus the size of one of the partitions if they are of equal size Linear RAID Linear RAID is a simple grouping of drives to create a larger virtual drive In
187. ed to the PXE boot directory tftpboot linux install lt os identifier gt The directory snapshot is created in the same directory as the root directory for example diskless i386 RHEL4 AS snapshot with a file called files in it This file contains a list of files and directories that must be read write for each diskless system Do not modify this file If additional entries must be added to the list create a files custom file in the same directory as the files file and add each additional file or directory on a separate line 4 5 Adding Hosts Each diskless client must have its own snapshot directory on the NFS server that is used as its read write file system The Network Booting Tool can be used to create these snapshot directories After completing the steps in Section 4 4 Finish Configuring the Diskless Environment a window ap pears to allow hosts to be added for the diskless environment Click the New button In the dialog shown in Figure 4 1 provide the following information Hostname or IP Address Subnet Specify the hostname or IP address of a system to add it as a host for the diskless environment Enter a subnet to specify a group of systems Operating System Select the diskless environment for the host or subnet of hosts Serial Console Select this checkbox to perform a serial installation Snapshot name Provide a subdirectory name to be used to store all of the read write content for the host
188. egabytes Disk label type msdos Minor Start End Type Filesystem Flags 1 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 remain ing 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 sdal The Start and End values are in megabytes The Type is one of primary extended or logical The Filesystem is the file system type which can be one of ext2 ext3 fatl6 fat32 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 In this example minor number 1 refers to the boot file system minor number 2 refers to the root file system minor number 3 refers to the swap and minor number 5 refers to the home file system Chapter 12 Managing Disk Storage 91 Om To select a different device without having to restart parted use the select command followed by the device name such as dev sda Then you can view its partition table or configure it 12 1 2 Creating a Partition waming Do not attempt to create a partition on a device that is in use Before creating a partition
189. el Note kernel hugemem is required for memory configurations higher than 16 GB PAE Physical Address Extension or 3 level paging on x86 processors that support PAE Support for multiple processors 4GB 4GB split 4GB of virtual address space for the kernel and almost 4GB for each user process on x86 systems kernel hugemem deve1 Contains the kernel headers and makefiles sufficient to build modules against the kernel hugemem package kernel smp Contains the kernel for multi processor systems The following are the key fea tures Multi processor support Support for more than 4 GB of RAM up to 16 GB for x86 PAE Physical Address Extension or 3 level paging on x86 processors that support PAE kernel smp devel Contains the kernel headers and makefiles sufficient to build modules against the kernel smp package kernel utils Contains utilities that can be used to control the kernel or system hardware kernel doc Contains documentation files from the kernel source Various portions of the Linux kernel and the device drivers shipped with it are documented in these files Installation of this package provides a reference to the options that can be passed to Linux kernel modules at load time By default these files are placed in the usr share doc kernel doc lt version gt directory Note The kernel source package has been removed and replaced with an RPM that can only b
190. el 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 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 9 Redundant Array of Independent Disks RAID 75 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 dedicat
191. el as listed in the foomatic database After removing the printer from the Printer Configuration Tool configuration restart the printer daemon for the changes to take effect as root service cups restart If all printers have been removed and you do not want to run the printer daemon anymore execute the following command as root service cups stop 34 11 3 Setting the Default Printer To set the default printer use the following command and specify the queuename system config printer tui Xdefault queue queuename 34 12 Managing Print Jobs When you send a print job to the printer daemon such as printing a text file from Emacs or printing an image from The GIMP the print job is added to the print spool queue The print spool queue is a list of print jobs that have been sent to the printer and information about each print request such as the status of the request the username of the person who sent the request the hostname of the system that sent the request the job number and more If you are running a graphical desktop environment click the Printer Manager icon on the panel to start the GNOME Print Manager as shown in Figure 34 13 Printer Edit View Help an gt z 1 Printer hi Figure 34 13 GNOME Print Manager To change the printer settings right click on the icon for the printer and select Properties The Printer Configuration Tool is then started Double click on a configured printer to vie
192. 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 or KDE desktop environment After the authentication expires the default is five minutes the icon disappears 234 Chapter 28 Console Access The user can select to forget the cached authentication by clicking on the icon and selecting the option to forget authentication 28 6 The floppy Group If for whatever reason console access is not appropriate for you and your non root users are required access to your system s diskette drive this can be done using the floppy group Add the user s to the floppy group using the tool of your choice For example the goasswd command can be used to add user fred to the floppy group gpasswd a fred floppy Now user fred is able to access the system s diskette drive from the console Chapter 29 Date and Time Configuration The Time and Date Properties Tool allows the user to change the system date and time to con f
193. er By default printers configured with the Printer Configuration Tool are not shared To share a configured printer start the Printer Configuration Tool and select a printer from the list Then select Action gt Sharing from the pulldown menu Note If a printer is not selected Action gt Sharing only shows the system wide sharing options normally shown under the General tab On the Queue tab select the option to make the queue available to other users Chapter 34 Printer Configuration 273 Queue General Z This queue is available to other computers Allowed hosts Add Edit Remove T Help 3 Cancel 2 OK Figure 34 17 Queue Options After selecting to share the queue by default all hosts are allowed to print to the shared printer Allowing all systems on the network to print to the queue can be dangerous especially if the system is directly connected to the Internet It is recommended that this option be changed by selecting the All hosts entry and clicking the Edit button to display the window shown in Figure 34 18 If you have a firewall configured on the print server it must be able to send and receive connections on the incoming UDP port 631 If you have a firewall configured on the client the computer sending the print request it must be allowed to send and accept connections on port 631 Choose which other computers may u
194. er 9 Redundant Array of Independent Disks RAID 9 1 What is RAID The basic idea behind RAID is to combine multiple small inexpensive disk drives into an array to accomplish performance or redundancy goals not attainable with one large and expensive drive This array of drives appears to the computer as a single logical storage unit or drive RAID is a method in which information is spread across several disks RAID uses 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 to increase bandwidth for reading or writing to disks and to maximize the ability to recover from hard disk crashes The underlying concept of RAID is that data may be distributed across each drive in the array in a consistent manner To do this the data must first be broken into consistently sized chunks often 32K or 64K in size although different sizes can be used Each chunk is then written to a hard drive in the RAID array according to the RAID level used When the data is to be read the process is reversed giving the illusion that the multiple drives in the array are actually one large drive 9 2 Who Should Use RAID Those who need to keep large quantities of data on hand such as system administrators would benefit by using RAID technology Primary reasons to use RAID include Enhanced speed Increased storage capacity using a single virt
195. er describes how to boot into rescue mode single user mode and emergency mode where you can use your own knowledge to repair the system 5 1 Common Problems You might need to boot into one of these recovery modes for any of the following reasons e You are unable to boot normally into Red Hat Enterprise Linux runlevel 3 or 5 e You are having hardware or software problems and you want to get a few important files off of your system s hard drive You forgot the root password 5 1 1 Unable to Boot into Red Hat Enterprise Linux This problem is often caused by the installation of another operating system after you have installed Red Hat Enterprise Linux Some other operating systems assume that you have no other operating system s on your computer They overwrite the Master Boot Record MBR that originally contained the GRUB boot loader If the boot loader is overwritten in this manner you cannot boot Red Hat Enterprise Linux unless you can get into rescue mode and reconfigure the boot loader Another common problem occurs when using a partitioning tool to resize a partition or create a new partition from free space after installation and it changes the order of your partitions If the partition number of your partition changes the boot loader might not be able to find it to mount the partition To fix this problem boot in rescue mode and modify the boot grub grub conf file For instructions on how to reinstall the GRUB bo
196. ernet devices and prompts you to configure them If you configured them during the installation they are displayed in the hardware list on the Hardware tab 5 If you selected Other Wireless Card the Select Ethernet Adapter window appears Select the manufacturer and model of the Ethernet card and the device If this is the first Ethernet card for the system select ethO 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 18 12 configure the settings for the wireless device Mode Auto Channel 1 Transmit Rate Auto Key use Ox for hex Network Name SSID Auto O Specified Configure Wireless Connection Py 3 Cancel lt Back D Eorward Figure 18 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 18 13 Chapter 18 Network Configuration 141 File Profi
197. ertificate for your secure server A secure server uses a certificate to identify itself to Web browsers You can generate your own certificate called a self signed certificate or you can get a certificate from a CA A certificate from a reputable CA guarantees that a website is associated with a particular company or organization Alternatively you can create your own self signed certificate Note however that self signed certifi cates should not be used in most production environments Self signed certificates are not automati cally accepted by a user s browser users are prompted by the browser to accept the certificate and 214 Chapter 26 Apache HTTP Secure Server Configuration create the secure connection Refer to Section 26 5 Types of Certificates for more information on the differences between self signed and CA signed certificates Once you have a self signed certificate or a signed certificate from the CA of your choice you must install it on your secure server 26 4 Using Pre Existing Keys and Certificates If you already have an existing key and certificate for example if you are installing the secure server to replace another company s secure server product you can probably use your existing key and certificate with the secure server The following two situations provide instances where you are not able to use your existing key and certificate If you are changing your IP address or domain name Certific
198. ervername gt lt sharename gt mnt point Chapter 23 Samba 185 This command mounts lt sharename gt from lt servername gt in the local directory mnt point 23 4 Additional Resources For configuration options not covered here please refer to the following resources 23 4 1 Installed Documentation smb conf man page explains how to configure the Samba configuration file smbd man page describes how the Samba daemon works e smbclient and findsmb man pages learn more about these client tools e usr share doc samba lt version number gt docs help files included with the samba package 23 4 2 Useful Websites http www samba org The Samba webpage contains useful documentation information about mailing lists and a list of GUI interfaces http www samba org samba docs using_samba toc html an online version of Using Samba 2nd Edition by Jay Ts Robert Eckstein and David Collier Brown O Reilly amp Associates 186 Chapter 23 Samba Chapter 24 Dynamic Host Configuration Protocol DHCP Dynamic Host Configuration Protocol DHCP is a network protocol for automatically assigning TCP IP information to client machines Each DHCP client connects to the centrally located DHCP server which returns that client s network configuration including the IP address gateway and DNS servers 24 1 Why Use DHCP DHCP is useful for automatic configuration of client network interfaces When con
199. es and enable or disable the firewall If Enable firewall was selected the options selected are translated to iptables commands and written to the etc sysconfig iptables file The iptables service is also started so that the firewall is activated immediately after saving the selected options If Disable firewall was selected the etc sysconfig iptables file is removed and the iptables service is stopped immediately The options selected are also written to the etc sysconfig system config securitylevel file so that the settings can be restored the next time the application is started Do not edit this file by hand Even though the firewall is activated immediately the iptables service is not configured to start automatically at boot time refer to Section 19 2 Activating the iptables Service for details 19 2 Activating the iptables Service The firewall rules are only active if the iptables service is running To manually start the service use the command sbin service iptables restart To ensure that it is started when the system is booted issue the command sbin chkconfig level 345 iptables on 156 Chapter 19 Basic Firewall Configuration The ipchains service is not included in Red Hat Enterprise Linux However if ipchains is in stalled for example an upgrade was performed and the system had ipchains previously installed the ipchains service should not be activated along with the iptables service To make sure the ipchains
200. eseeeeesaeseeeeeeees 138 18 7 Establishing a Wireless Connection eseeesesesceteeeesescseseeseeseeseseseeeees 139 18 8 Managing DNS Settings s 18 9 Managing Host eec E ER AEE E EETA EENS 142 18 10 Working with Profiles vespere yatosi as E TE 18 11 Device Aliases eee 18 12 Establishing an IPsec Connection cee eeeseseseeeesescseseeeeteeseseaeeenes 146 18 13 Saving and Restoring the Network Configuration 0 cece eeteeeeeeneee 151 19 Basic Firewall Configuration 00 eeseeeeeeeeeeees 153 19 1 Security Level Configuration Tool 19 2 Activating the iptables Service 20 Controlling Access to Services 20 1 Runlevels 20 2 TCP Wrapperts 20 3 Services Configuration Tool 0 0 0 0 cece eee ce csesescsceeeecasseseeseesseneeaees 159 20 4 ntsysv 20 3 CHK CONE LG nrn gan dd a ara E E A aO E 161 20 6 Additional Resources case csicssiscssetisscsiedssveva casas sands suedecstvosdesacaetecavascataddeagaeerss 161 21 OpenSSH eee 163 21 1 Why Use OpenSSH 00 21 2 Configuring an OpenSSH Server 21 3 Configuring an OpenSSH Client 21 4 Additional Resources 168 22 Network File System NFS 169 22 1 Why Use NFS nesens 169 22 2 Mounting NFS File Systems 169 22 3 Exporting NFS File Systems cecsscssssccssesessecceceseeeeseeceseeeesceaceeeseeeeeeaeereaes 171 22 4 Additional RESOUIC
201. esponds to the Operating system identifier field in Figure 3 1 If FTP is selected as the installation protocol and anonymous login is not available specify a user name and password for login with the following options before lt os identifer gt in the previous command A 0 u lt username gt p lt password gt For more information on command line options available for the pxeos command refer to the pxeos man page 3 3 Adding PXE Hosts After configuring the network server the interface as shown in Figure 3 2 is displayed Eile Configure Help se f 8 New Properties Delete Hostname operating System lip Address 4 gt Figure 3 2 Add Hosts 46 Chapter 3 PXE Network Installations The next step is to configure which hosts are allowed to connect to the PXE boot server For the command line version of this step refer to Section 3 3 1 Command Line Configuration To add hosts click the New button Hostname or IP Address Subnet client example com Operating System thel 4 as C Serial Console Diskless OS Network OS Install Snapshot name Kickstart File Ethernet t r 3 Cancel 2 OK Figure 3 3 Add a Host Enter the following information e Hostname or IP Address Subnet The IP address fully qualified hostname or a subnet of systems that should be allowed to connect to the PXE server for installations O
202. ess of the private subnet behind the other IPsec router In our example enter 192 168 1 0 if configuring ipsecl and enter 192 168 2 0 if configuring ipsec0 Remote Subnet Mask The subnet mask of the remote IP address Remote Network Gateway The IP address of the gateway for the remote network address 150 Chapter 18 Network Configuration If manual encryption was selected in step 6 specify the encryption key to use or click Gen erate to create one Specify an authentication key or click Generate to generate one It can be any combination of numbers and letters Click Forward to continue IPsec Remote Network Please enter your remote network settings Remote IP Address 172 16 57 27 Remote Subnet Mask 255 255 255 0 Remote Network Gateway 192 1681 1 2 Cancel lt Back gt Eorward Figure 18 22 Remote Network Information 9 Verify the information on the IPsec Summary page and click Apply 10 Select File gt Save to save the configuration 11 Select the IPsec connection from the list and click the Activate button 12 As root at a shell prompt enable IP forwarding a Edit etc sysctl conf and set net ipv4 ip_forwardto 1 b Execute the following command to enable the change sbin sysctl p etc sysctl conf The network script to activate the IPsec connection automatically creates network routes to send pack ets through the IPsec router if necessa
203. essary to specify them in the packages section Here is an example packages selection Spackages X Window System Chapter 1 Kickstart Installations 19 GNOME Desktop Environment Graphical Internet Sound and Video dhcp As you can see groups are specified one to a line starting with an symbol a space and then the full group name as given in the comps xm1 file Groups can also be specified using the id for the group such as gnome desktop Specify individual packages with no additional characters the dhcp line in the example above is an individual package You can also specify which packages not to install from the default package list autofs The following options are available for the packages option resolvedeps Install the listed packages and automatically resolve package dependencies If this option is not specified and there are package dependencies the automated installation pauses and prompts the user For example Spackages resolvedeps ignoredeps Ignore the unresolved dependencies and install the listed packages without the dependencies For example Spackages ignoredeps ignoremissing Ignore the missing packages and groups instead of halting the installation to ask if the installation should be aborted or continued For example Spackages ignoremissing 1 6 Pre installation Script You can add commands to run on the system immediately after the ks cfg has been parsed
204. est along with documents proving your identity to a CA Red Hat does not make recommendations on which certificate authority to choose Your decision may be based on your past experiences on the experiences of your friends or colleagues or purely on monetary factors Once you have decided upon a CA you need to follow the instructions they provide on how to obtain a certificate from them 4 When the CA is satisfied that you are indeed who you claim to be they provide you with a digital certificate 5 Install this certificate on your secure server and begin handling secure transactions Whether you are getting a certificate from a CA or generating your own self signed certificate the first step is to generate a key Refer to Section 26 6 Generating a Key for instructions 26 6 Generating a Key You must be root to generate a key 216 Chapter 26 Apache HTTP Secure Server Configuration First use the cd command to change 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 create your own random key Change to the usr share ssl certs directory and type in the following command make genkey Your system displays a message similar to the following umask 77 usr bin openssl genrsa des3 1024 gt etc httpd conf ssl key server key Generating RSA private key 1024 bit long modulus
205. evices system devices and video cards Click on the category name in the left menu and the information is displayed File CD ROM Drives Selected Device Fl Disk in ety LG CD ROM CRD 84 amp 4B Hard Drives Keyboards Network devices Pointing devices Device Information RAID devices Manufacturer LG SCSI devices Driver none or built in System devices Device dev hda USB devices Video cards Figure 40 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 00 00 0 Host bridge ServerWorks CNB20LE Host Bridge rev 06 00 00 1 Host bridge ServerWorks CNB20LE Host Bridge rev 06 00 01 0 VGA compatible controller S3 Inc Savage 4 rev 04 00 02 0 Ethernet controller Intel Corp 82557 8 9 Ethernet Pro 100 rev 08 00 0f 0 ISA bridge ServerWorks OSB4 South Bridge rev 50 00 0f 1 IDE interface ServerWorks OSB4 IDE Controller 00 0f 2 USB Controller ServerWorks OSB4 CSB5 OHCI USB Controller rev 04 01 03 0 SCSI storage controller Adaptec AIC 7892P U160 m rev 02 01 05 0 RAID bus controller IBM ServeRAID Controller The 1spci is also useful to determine the network card in your system if you do not know the manu facturer or model number 306 Chapter 40 Gathering
206. example Module Size Used by nfs 218437 1 lockd 63977 2 nfs parport_pc 24705 1 lp 12077 0 parport 37129 2 parport_pc lp autofs4 23234 2 i2c_dev 11329 0 294 Chapter 38 Kernel Modules i2c_core 22081 1 i2c_dev sunrpc 157093 5 nfs lockd button 6481 0 battery 8901 0 ac 4805 0 md5 4033 1 ipv6 232833 16 ohci_hcd 21713 O e100 39493 0 mii 4673 1 e100 floppy 58481 0 sg 33377 0 dm_snapshot 17029 0 dm_zero 2369 0 dm_mirror 22957 2 ext3 116809 2 jbd 71257 1 ext3 dm_mod 54741 6 dm_snapshot dm_zero dm_mirror ips 46173 2 aic7xxx 148121 0 sd_mod 17217 3 scsi_mod 121421 4 sg ips aic7xxx sd_mod For each line the first column is the name of the module the second column is the size of the module and the third column is the use count The sbin lsmod output is less verbose and easier to read than the output from viewing proc modules To load a kernel module use the sbin modprobe command followed by the kernel module name By default modprobe attempts to load the module from the lib modules lt kernel version gt kernel drivers subdirectories There is a subdirectory for each type of module such as the net subdirectory for network interface drivers Some kernel modules have module dependencies meaning that other modules must be loaded first for it to load The sbin modprobe command checks for these dependencies and loads the module dependencies before loading the specified module For example the command s
207. example in an XTerm or GNOME terminal If the X Window System is not running the text based version of the tool is started Select the appropriate mouse for the system 2 Button Mouse USB 3 Button Mouse USB 3 Button Mouse serial Wheel Mouse USB U 2 Button Mouse serial 2 Button Mouse PS 2 3 Button Mouse PS 2 b Kensington Ia Emulate 3 button click Serial devices 2 OK Figure 31 1 Select Mouse Select the new mouse type for the system If the specific mouse model is not listed select one of the Generic entries based on the mouse s number of buttons and its interface If there is not an exact match select the generic match that is most compatible with the system and the mouse The built in pointing device such as a touch pad on a laptop computer is usually PS 2 compatible All the mouse types are appended with PS 2 serial or USB in parentheses This specifies the mouse port A PS 2 mouse port looks similar to A serial mouse port looks similar to CG3 A USB mouse port looks similar to Select the Generic Wheel Mouse entry with the proper mouse port to enable the scroll button on the mouse 242 Chapter 31 Mouse Configuration The scroll button on a wheel mouse can be used as the middle mouse button for cutting text pasting text and other middle mouse button functions If the mouse only has two buttons select Emulate 3
208. example in an XTerm or a GNOME terminal File Actions Edit Runlevel Help gt o au Start Stop Restart Save Revert Currently Running in Runlevel 5 Editing Runlevel 5 a Description Startup shutdown script for the Common UNIX cups Printing System CUPS cups Ipd crond _ daytime _ daytime udp dbskkd cdb dhcpd dhcrelay echo echo udp Status cupsd pid 1961 is running eklogin finger firstboot gpm gssftp x hpoj httpd identd Figure 20 1 Services Configuration Tool The Services Configuration Tool displays the current runlevel as well as the runlevel you are cur rently editing To edit a different runlevel select Edit Runlevel from the pulldown menu and select runlevel 3 4 or 5 Refer to Section 20 1 Runlevels for a description of runlevels The Services Configuration Tool lists the services from the etc rc d init d directory as well as the services controlled by xinetd Click on the name of the service from the list on the left hand side of the application to display a brief description of that service as well as the status of the service If the service is not an xinetd service the status window shows whether the service is currently running If the service is controlled by xinetd the status window displays the phrase xinetd service To start stop or
209. ey are started on or stopped off in runlevels 0 6 At the end of the list is a section for the services managed by xinetd If the chkconfig list command is used to query a service managed by xinetd it displays whether the xinetd service is enabled on or disabled off For example the command chkconfig list finger returns the following output finger on As shown finger is enabled as an xinetd service If xinetd is running finger is enabled If you use chkconfig list to query a service in etc rc d service s settings for each runlevel are displayed For example the command chkconfig list httpd returns the following output httpd O off l off 2 on 3 0n 4 on 5 on 6 0ff chkconfig can also be used to configure a service to be started or not in a specific runlevel For example to turn nscd off in runlevels 3 4 and 5 use the following command chkconfig level 345 nscd off waming Services managed by xinetd are immediately affected by chkconfig For example if xinetd is running finger is disabled and the command chkconfig finger on is executed finger is im mediately enabled without having to restart xineta manually Changes for other services do not take effect immediately after using chkconfig You must stop or start the individual service with the command service daemon stop In the previous example replace daemon with the name of the service you want to stop for example httpd Replace stop with start or rest
210. figuration 2 8 Display Configuration y 2 9 Package Selection sssssrre to seyv sities t o rE A VE T EENE LS AANS 2 10 Pre Installation Script sses Ansas i endeared SES EA ERE eS 39 2 11 Post Installation Script 40 2 12 Saving the File we 42 3 PXE Network Installations 3 1 Setting up the Network Server 3 2 PXE Boot Configuration 43 3 3 Adding PXE HOSt8 iss lsvesccssccuvsyssavessetecsssys siveuesd ATEEN EASES VEETEE S 45 I4 Starine the tt tp Server Akere resene ekesti r L ESE IEEE LE EAEE 3 5 Configuring the DHCP Server bs 3 6 Adding a Custom Boot Message eccccceeeseseeseeesesesssseessceeseeessnessesenenesaeseaas 47 3 7 Performing the PXE Installation ceeeeeceseeseeeseeeeecseesesecseeecneneeneeaeeecseeeeneenes 47 4 Diskless Environments 1 49 4 1 Start the tftp Server 1 49 4 2 Configuring the DHCP Server 4 3 Configuring the NFS Server 4 4 Finish Configuring the Diskless Environment g 4S Adding HOStS sick erae aee EE E EE AEE E EESO E IERSE EA EE s 51 A6 Booting the Hosts inoun a aa A A O 51 5 Basic System Recovery se 5 1 Common Problems siena aae a AE naa a EE ATEA 53 5 2 Booting into Rescue Modes seesinane Aa E 53 5 3 Booting into Single User Mode 0 cecccccesescsesseeescseseeseseececseeseeesseseseeeeesas 56 5 4 Booting into Emergency Mode II File Systems 6 The exh File Sry Sterns r u a Eo a EAEE EE RA NEn nA SE 6 1 Fea
211. figuration 169 diskless environment configuring for 50 exporting 171 hostname formats 174 mounting 169 over TCP 171 starting the server 175 status of the server 174 stopping the server 175 NFS Server Configuration Tool 171 NIS 224 NTP configuring 236 ntpd 236 ntpd 236 ntsysv 160 O O Reilly amp Associates Inc 175 208 opannotate see OProfile opcontrol see OProfile OpenLDAP 224 225 openldap clients 224 OpenSSH 163 additional resources 168 client 164 scp 164 sftp 165 ssh 164 DSA keys generating 166 generating key pairs 165 RSA keys generating 166 RSA Version 1 keys generating 167 server 163 etc ssh sshd_config 163 starting and stopping 163 ssh add 168 ssh agent 168 with GNOME 167 ssh keygen DSA 166 RSA 166 RSA Version 1 167 OpenSSL additional resources 168 opreport see OProfile see OProfile OProfile 307 dev oprofile 315 additional resources 318 configuring 308 separating profiles 311 events sampling rate 310 setting 309 monitoring the kernel 308 opannotate 315 opcontrol 308 no vimlinux 308 start 312 vimlinux 308 opreport 313 on a single executable 314 oprofiled 312 log file 312 op_help 310 overview of tools 307 reading data 312 saving data 312 starting 312 unit mask 311 oprofiled see OProfile oprof_start 316 op_help 310 P Package Management Tool 121 installing packages 122 removing packages 123
212. figuring the client system the administrator can choose DHCP and instead of entering an IP address netmask gateway or DNS servers The client retrieves this information from the DHCP server DHCP is also useful if an administrator wants to change the IP addresses of a large number of systems Instead of reconfiguring all the systems he can just edit one DHCP configuration file on the server for the new set of IP addresses If the DNS servers for an organization changes the changes are made on the DHCP server not on the DHCP clients Once the network is restarted on the clients or the clients are rebooted the changes take effect Furthermore if a laptop or any type of mobile computer is configured for DHCP it can be moved from office to office without being reconfigured as long as each office has a DHCP server that allows it to connect to the network 24 2 Configuring a DHCP Server To configure a DHCP server the etc dhcpd conf configuration file must be created A sample file can be found at usr share doc dhcp lt version gt dhcpd conf sample DHCP also uses the file var 1ib dhcp dhcpd leases to store the client lease database Refer to Section 24 2 2 Lease Database for more information 24 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 while other options can be declared
213. for individual client systems The configuration file can contain extra tabs or blank lines for easier formatting 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 Internet Engineering Task Force 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 versions used the ad hoc mode however it has been deprecated To keep the same behavior add the following line to the top of the configuration file ddns update style ad hoc To use the recommended mode add the following line to the top of the configuration file ddns update style interim 188 Chapter 24 Dynamic Host Configuration Protocol DHCP Refer to the dhcpd conf man page for details about the different modes 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
214. from the list and click the Activate button Repeat for the other host It is extremely important that the same keys from step 8 be used on the other hosts Otherwise IPsec does not work After configuring the IPsec connection it appears in the IPsec list as shown in Figure 18 19 148 Chapter 18 Network Configuration File Profile Help B f B x New Edit Copy Delete Activate Deactivate Devices Hardware IPsec DNS Hosts You may configure IPsec tunnels and host to host connections here Profile Type Destination Nickname 00 psecO Figure 18 19 IPsec Connection Two files are created in the etc sysconfig network scripts directory ifcfg lt nickname gt and keys lt nickname gt If automatic encryption is selected etc racoon racoon conf is created as well When the interface is activated lt remote ip gt conf and psk txt are created in etc racoon and racoon conf is modified to include lt remote ip gt conf Refer to Section 18 12 3 Testing the IPsec Connection to determine if the IPsec connection has been successfully established 18 12 2 Network to Network VPN Connection A network to network IPsec connection uses two IPsec routers one for each network through which the network traffic for the private subnets is routed For example as shown in Figure 18 20 if the 192 168 0 24 private network sends network traffic to t
215. fstab for the home partition dev VolGroup00 LogVo102 and the command edquota testuser is executed the following is shown in the editor configured as the default for the system Disk quotas for user testuser uid 501 Filesystem blocks soft hard inodes soft hard dev VolGroup00 LogVol02 440436 0 0 37418 0 0 i Note The text editor defined by the EDITOR environment variable is used by edquota To change the editor set the EDITOR environment variable in your bash_profile file to the full path of the editor of your choice The first column is the name of the file system that has a quota enabled for it The second column shows how many blocks the user is currently using The next two columns are used to set soft and hard block limits for the user on the file system The inodes column shows how many inodes the user is currently using The last two columns are used to set the soft and hard inode limits for the user on the file system A hard limit is the absolute maximum amount of disk space that a user or group can use Once this limit is reached no further disk space can be used The soft limit defines the maximum amount of disk space that can be used However unlike the hard limit the soft limit can be exceeded for a certain amount of time That time is known as the grace period The grace period can be expressed in seconds minutes hours days weeks or months If any of the values are set to 0 that limit is not set In the text
216. fter changing any of the settings log out of the graphical desktop and log back in to enable the changes 32 1 Display Settings The Display tab allows users to change the resolution and color depth The display of a monitor consists of tiny dots called pixels The number of pixels displayed at one time is called the resolution For example the resolution 1024x768 means that 1024 horizontal pixels are used and 768 vertical pixels are used The higher the resolution numbers the more images the monitor can display at one time For example the higher the resolution the smaller the desktop icons appear and the more icons it takes to fill the entire desktop The color depth of the display determines how many possible colors are displayed The higher the color depth the more contrast between colors Settings Hardware Dual head Please select the resolution and color depth that you wish to use gt Resolution 1024x768 S Color Depth Millions of Colors Cancel 2 OK Figure 32 1 Display Settings 244 Chapter 32 X Window System Configuration 32 2 Display Hardware Settings When the application is started it probes the monitor and video card If the hardware is probed prop erly the information for it is shown on the Hardware tab as shown in Figure 32 2 Settings Hardware Dual head Tal Monitor Type LCD Pa
217. fy more than one unit mask the hexadecimal values must be combined using a bitwise or operation opcontrol event lt event name gt lt sample rate gt lt unit mask gt 41 2 3 Separating Kernel and User space Profiles By default kernel mode and user mode information is gathered for each event To configure OProfile not to count events in kernel mode for a specific counter execute the following command opcontrol event lt event name gt lt sample rate gt lt unit mask gt 0 Execute the following command to start profiling kernel mode for the counter again opcontrol event lt event name gt lt sample rate gt lt unit mask gt 1 To configure OProfile not to count events in user mode for a specific counter execute the following command opcontrol event lt event name gt lt sample rate gt lt unit mask gt lt kernel gt 0 Execute the following command to start profiling user mode for the counter again opcontrol event lt event name gt lt sample rate gt lt unit mask gt lt kernel gt 1 When the OProfile daemon writes the profile data to sample files it can separate the kernel and library profile data into separate sample files To configure how the daemon writes to sample files execute the following command as root opcontrol separate lt choice gt lt choice gt can be one of the following none do not separate the profiles default e library generate per application profile
218. g ggv 2 6 0 2 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 Enter the following command rpm Vf usr bin paste and the appropriate package is verified Do you want to find out more information about a particular program You can try the following command to locate the documentation which came with the package that owns that program rpm qdf usr bin free The output would be similar to the following usr share doc procps 3 2 3 BUGS usr share doc procps 3 2 3 FAQ usr share doc procps 3 2 3 NEWS usr share doc procps 3 2 3 TODO usr share man manl free 1 gz usr share man manl pgrep 1 gz asr share man manl pkill 1 gz usr share man manl pmap 1 gz ausr share man manl ps 1 gz usr share man manl skill 1 gz usr share man manl1 slabtop 1 gz usr share man manl snice 1 gz usr share man manl tload 1 gz usr share man manl top 1 gz usr share man manl uptime 1 gz usr share man manl w 1 gz usr share man manl watch 1 gz asr share man man5 sysctl conf 5 gz usr share man man8 sysct1 8 gz ausr share man man8 vmstat 8 gz You may find a new RPM but you do not know what it does To find information about it use the following command rpm qip crontabs 1 10 7 noarch rpm The output would be similar to the following Name crontabs Relocations not rel
219. g a New Group we 249 33 4 Modifying Group Properties 0 0 00 iereire cee sioss kartesia isIE RIESA IE EESTE eoan 249 33 5 Command Line Configuration 00 0 0 ccc ceeeeeeceesescsceeceeeeseseeeeeeesseseeeeeeaes 250 33 6 Explaining the Process se DIS 33 7 Additional Information 254 34 Printer Configuration 257 34 1 Adding a Local Printer 258 34 2 Adding an IPP Printer 0 0 ias 259 34 3 Adding a Remote UNIX LPD Printer 260 34 4 Adding a Samba SMB Printer 261 34 5 Adding a Novell NetWare NCP Printer 262 34 6 Adding a JetDirect Printer ssis sirensis 263 34 7 Selecting the Printer Model and Finishing ccsesseceseeceseeeeeeeseeeeeeeeeseenes 264 34 8 Printing a Test Page 34 9 Modifying Existing Printers oaoaraa aie A ENEE REES 266 34 10 Saving the Configuration File eeseseessessseeseesrsrsseeserreresseserersrereseeresrersseerereee 268 34 11 Command Line Configuration 268 34 12 Managing Print Jobs 270 34 13 Sharing a Printer 34 14 Additional Resources 35y Automated Tasks Z ies eneren oer EEEE EEE EET E NTA ein 275 35 3 Additional RESOULCES ciecscsileoes cruvacessstevevedddcisnteseen REDEA ENA R 279 281 281 281 282 36 LOg Piles ices oers enk 36 1 Locating Log Files 36 2 Viewing Log Files 36 3 Adding a Log File 36 4 Examining Log Files 283 3
220. g accessed by the public at large your secure server needs a certificate signed by a CA so that people who visit your website know that the website is owned by the organiza tion who claims to own it Before signing a certificate a CA verifies that the organization requesting the certificate was actually who they claimed to be Most Web browsers that support SSL have a list of CAs whose certificates they automatically accept If a browser encounters a certificate whose authorizing CA is not in the list the browser asks the user to either accept or decline the connection You can generate a self signed certificate for your secure server but be aware that a self signed cer tificate does not provide the same functionality as a CA signed certificate A self signed certificate is not automatically recognized by most Web browsers and does not provide any guarantee concerning the identity of the organization that is providing the website A CA signed certificate provides both of these important capabilities for a secure server If your secure server is to be used in a production environment a CA signed certificate is recommended 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 requ
221. g guidelines passwd lt username gt Command line options for useradd are detailed in Table 33 1 Home directory to be used instead of default home username Date for the account to be disabled in the format YY Y Y MM DD Chapter 33 User and Group Configuration 251 Option Description o Number of days after the password expires until the account is disabled If 0 is specified the account is disabled immediately after the password expires If 1 is specified the account is not be disabled after the password expires g group name Group name or group number for the user s default group The group must exist prior to being specified here G group list List of additional other than default group names or group numbers separated by commas of which the user is a member The groups must exist prior to being specified here Create a system account with a UID less than 500 and without a home directory The password encrypted with crypt User s login shell which defaults to bin bash User ID for the user which must be unique and greater than 499 Table 33 1 useradd Command Line Options Create the home directory if it does not exist 33 5 2 Adding a Group To add a group to the system use the command groupadd groupadd lt group name gt Command line options for groupadd are detailed in Table 33 2 Group ID for the group which must be unique and greater than 499 Create a system group with a GID less tha
222. ger allows you to view modify add and delete local users and groups To use the User Manager you must be running the X Window System have root privileges and have the system config users RPM package installed To start the User Manager from the desktop go to Applications the main menu on the panel gt System Settings gt Users amp Groups Or type the command system config users at a shell prompt for example in an XTerm or a GNOME terminal File Preferences Help BG Add User Add Group Properties Help Refresh Search filter Apply filter Users Groups User Name User D v Primary Group Full Name Login Shell Home Directory tfox 500 tfox Tammy Fox bin bash home tfox bfox 501 bfox Brent Fox bin bash home bfox Figure 33 1 User Manager To view a list of local users on the system click the Users tab To view a list of local groups on the system click the Groups tab To find a specific user or group type the first few letters of the name in the Search filter field Press Enter or click the Apply filter button The filtered list is displayed To sort the users or groups click on the column name The users or groups are sorted by the value of that column Red Hat Enterprise Linux reserves user IDs below 500 for system users By default User Manager does not display system users To view all users including the system users uncheck Preferences gt Filter s
223. gle piece of hardware X Inactive tO trO Token Ring Figure 18 11 Token Ring Device Be sure to select File gt Save to save the changes After adding the device you can edit its configuration by selecting the device from the device list and clicking Edit For example you can configure whether the device is started at boot time When the device is added it is not activated immediately as seen by its Inactive status To activate the device select it from the device list and click the Activate button If the system is configured to activate the device when the computer starts the default this step does not have to be performed again 140 Chapter 18 Network Configuration 18 7 Establishing a Wireless Connection Wireless Ethernet devices are becoming increasingly popular The configuration is similar to the Eth ernet configuration except that it allows you to configure settings such as the SSID and key for the wireless device To add a wireless Ethernet connection follow these steps 1 Click the Devices tab 2 Click the New button on the toolbar 3 Select Wireless connection from the Device Type list and click Forward 4 If you have already added the wireless network interface card to the hardware list select it from the Wireless card list Otherwise select Other Wireless Card to add the hardware device Note The installation program usually detects supported wireless Eth
224. gure 18 2 Ethernet Settings After configuring the Ethernet device it appears in the device list as shown in Figure 18 3 File Profile Help Br B 7 x New Edit Copy Delete Activate Deactivate Devices Hardware IPsec DNS Hosts 7 You may configure network devices associated with a iz physical hardware here Multiple logical devices can be i associated with a single piece of hardware Profile Status Device Nickname Type e ethO eth0 Figure 18 3 Ethernet Device Be sure to select File gt Save to save the changes After adding the Ethernet device you can edit its configuration by selecting the device from the device list and clicking Edit For example when the device is added it is configured to start at boot time by default To change this setting select to edit the device modify the Activate device when computer starts value and save the changes When the device is added it is not activated immediately as seen by its Inactive status To activate the device select it from the device list and click the Activate button If the system is configured to activate the device when the computer starts the default this step does not have to be performed again If you associate more than one device with an Ethernet card the subsequent devices are device aliases A device alias allows you to setup multiple virtual devices for one physical device thus g
225. hapter 2 Kickstart Configurator 2 11 1 Chroot Environment To run the post installation script outside of the chroot environment click the checkbox next to this option on the top of the Post Installation window This is equivalent to using the nochroot option in the post section To make changes to the newly installed file system within the post installation section but outside of the chroot environment you must prepend the directory name with mnt sysimage For example if you select Run outside of the chroot environment the previous example must be changed to the following echo Hackers will be punished gt mnt sysimage etc motd 2 11 2 Use an Interpreter To specify a scripting language to use to execute the script select the Use an interpreter option and enter the interpreter in the text box beside it For example usr bin python2 2 can be specified for a Python script This option corresponds to using bpost interpreter usr bin python2 2 in your kickstart file 2 12 Saving the File To review the contents of the kickstart file after you have finished choosing your kickstart options select File gt Preview from the pull down menu You have choosen the following configuration Click Save File to save the kickstart file Generated by Kickstart Configurator platform x86 AMD64 or Intel EM64T System language lang en_US Language modules to install langsupport it_LT default en_US System ke
226. hare the available free space on the disk 7 Select Force to be a primary partition if you want the partition to be a primary partition 8 Click OK to return to the main screen Repeat these steps 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 The following figure shows both drives completed after the repeated process 70 Chapter 8 LVM Configuration Disk Setup Drive dev sda 8676 MB Model IBM PSG ST39103LC 1 jsda2 573 me Choose where you would like Red Hat Enterprise Linux AS to Prive Mlev sdb 8676 MB Model IBM PSG ST39204LC 1 sdb 8675 MB be installed If you do not know how to partition your system or if you need help with using the New Edit Delete Reset RAID LVM manual partitioning tools refer 7 Mount Point Sia to the product documentation Device RAID Volume TYPE Foma tp Star End 7 Hard Drives If you used automatic mgA f Y dev sda partitioning you can either acceptthe current partition Idev sdal boot ext3 v w2 1 B settings click Next or modify Idev sda2 LVMPV v 8574 14 1106 the setup using the manual Idev sdb partitioning tool Idev sdb1 LvMPV 8676 1 1106 Ifyou are manually partitioning your system you can see your current hard drive s and F
227. hares using Samba 181 X X Configuration Tool display settings 243 dual head display settings 244 hardware settings 244 X Window System configuration 243 xDSL connection see network configuration xinetd 158 Y ypbind 224 Colophon The manuals are written in DocBook SGML v4 1 format The HTML and PDF formats are produced using custom DSSSL stylesheets and custom jade wrapper scripts The DocBook SGML files are written using Emacs with the help of PSGML mode Garrett LeSage created the admonition graphics note tip important caution and warning They may be freely redistributed with the Red Hat documentation The Red Hat Product Documentation Team consists of the following people Sandra A Moore Primary Writer Maintainer of the Red Hat Enterprise Linux Installation Guide for x86 Itanium AMD64 and Intel Extended Memory 64 Technology Intel EM64T Primary Writer Maintainer of the Red Hat Enterprise Linux Installation Guide for the IBM POWER Archi tecture Primary Writer Maintainer of the Red Hat Enterprise Linux Installation Guide for the IBM S 390 and IBM eServer zSeries Architectures John Ha Primary Writer Maintainer of the Red Hat Cluster Suite Configuring and Managing a Cluster Co writer Co maintainer of the Red Hat Enterprise Linux Security Guide Maintainer of custom DocBook stylesheets and scripts Edward C Bailey Primary Writer Maintainer of the Red Hat Enterprise Linux Int
228. he partitions Display list of available commands Create a disk label for the partition table mkfs minor num file system type Create a file system of type file system type mkpart part type fs type start mb Make a partition without creating a new file end mb system mkpartfs part type fs type start mb Make a partition and create the specified file end mb system move minor num start mb end mb Move the partition 90 Chapter 12 Managing Disk Storage name minor num name rescue start mb end mb resize minor num start mb end mb rm minor num select device set minor num flag state Name the partition for Mac and PC98 disklabels only Display the partition table Quit parted Rescue a lost partition from start mb to end mb Resize the partition from st art mb to end mb Remove the partition Select a different device to configure Set the flag on a partition st ate is either on or off Table 12 1 parted commands 12 1 1 Viewing the Partition Table After starting parted type the following command to view the partition table print A table similar to the following appears Disk geometry for dev sda 0 000 8678 789 megabytes Disk label type msdos Minor Start End Type Filesystem Flags 1 0 031 101 975 primary ext3 boot 2 101 975 5098 754 primary ext3 3 5098 755 6361 677 primary linux swap 4 6361 677 8675 727 extended 5 6361 708 7357 895 logical ext3 Disk geometry for dev hda 0 000 9765 492 m
229. he 192 168 2 0 24 private network the packets go through gateway0 to ipsecO through the Internet to ipsecl to gateway and to the 192 168 2 0 24 subnet The IPsec routers must have publicly addressable IP addresses as well as another Ethernet device connected to its private network Traffic only travels through it if it is intended for the other IPsec router with which it has an encrypted connection ipsecO Ipsect Internet gatewayO gateway1 lli 192 168 1 0 24 192 168 2 0 24 Figure 18 20 Network to Network IPsec Alternate network configurations options include a firewall between each IP router and the Internet and an Intranet firewall between each IPsec router and subnet gateway The IPsec router and the Chapter 18 Network Configuration 149 gateway for the subnet can be one system with two Ethernet devices one with a public IP address that acts as the IPsec router and one with a private IP address that acts as the gateway for the private subnet Each IPsec router can use the gateway for its private network or a public gateway to send the packets to the other IPsec router To configure a network to network IPsec connection use the following steps 1 2 3 4 nN Start the Network Administration Tool From the IPsec tab select New Click Forward to start configuring a network to network IPsec connection Provide a one word nickname such as ipsec
230. he driver diskette driverdisk source ftp path to dd img driverdisk source http path to dd img driverdisk source nfs host path to img Chapter 1 Kickstart Installations 7 lt partition gt Partition containing the driver disk type File system type for example vfat or ext2 firewall optional This option corresponds to the Firewall Configuration screen in the installation program firewall enabled disabled trust lt device gt port enabled Reject incoming connections that are not in response to outbound requests such as DNS replies or DHCP requests If access to services running on this machine is needed you can choose to allow specific services through the firewall disabled Do not configure any iptables rules trust Listing a device here such as eth0 allows all traffic coming from that device to go through the firewall To list more than one device use trust ethO trust ethl Do NOT use a comma separated format such as trust eth0 ethl lt incoming gt Replace with one or more of the following to allow the specified services through the fire wall ssh telnet smtp e http ftp port You can specify that ports be allowed through the firewall using the port protocol format For example to allow IMAP access through your firewall specify imap tcp Numeric ports can also be specified explicitly for example to allow UDP pa
231. he local system is as follows scp username tohostname lt remotefile gt lt newlocalfile gt The lt remotefile gt specifies the source including path and lt newlocalfile gt specifies the destination including path 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 21 3 3 Using the sttp Command The sftp utility can be used to open a secure interactive FTP session It is similar to ftp except that it uses a secure encrypted connection The general syntax is sftp username hostname com Once authenticated you can use a set of commands similar to those used by FTP Refer to the sftp man page for a list of these commands To read the man page execute the command man sftp ata shell prompt The sftp utility is only available in OpenSSH version 2 5 0p1 and higher 21 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
232. he output of the command cat proc swaps or free 11 3 Removing Swap Space Sometimes it can be prudent to reduce swap space after installation For example say you downgraded the amount of RAM in your system from 1 GB to 512 MB but there is 2 GB of swap space still assigned It might be advantageous to reduce the amount of swap space to GB since the larger 2 GB could be wasting disk space You have three options remove an entire LVM2 logical volume used for swap remove a swap file or reduce swap space on an existing LVM2 logical volume 11 3 1 Reducing Swap on an LVM2 Logical Volume To reduce an LVM2 swap logical volume assuming dev VolGroup00 LogVo101 is the volume you want to extend 1 Disable swapping for the associated logical volume swapoff v dev VolGroup00 LogVol01 2 Reduce the LVM2 logical volume by 512 MB lvm lvreduce dev VolGroup00 LogVol01 L 512M 3 Format the new swap space mkswap dev VolGroup00 LogVol01 4 Enable the extended logical volume swapon va 5 Test that the logical volume has been reduced properly cat proc swaps free 11 3 2 Removing an LVM2 Logical Volume for Swap The swap logical volume cannot be in use no system locks or processes on the volume The easiest way to achieve this it to boot your system in rescue mode Refer to Chapter 5 Basic System Recovery for instructions on booting into rescue mode When prompted to mount the file system select Skip To
233. heck command For example if user and group quotas are enabled for the home file system create the files in the home directory quotacheck cug home The c option specifies that the quota files should be created for each file system with quotas enabled the u option specifies to check for user quotas and the g option specifies to check for group quotas If neither the u or g options are specified only the user quota file is created If only g is specified only the group quota file is created After the files are created run the following command to generate the table of current disk usage per file system with quotas enabled quotacheck avug The options used are as follows e a Check all quota enabled locally mounted file systems e v Display verbose status information as the quota check proceeds e u Check user disk quota information e g Check group disk quota information Chapter 13 Implementing Disk Quotas 99 After quotacheck has finished running the quota files corresponding to the enabled quotas user and or group are populated with data for each quota enabled locally mounted file system such as home 13 1 4 Assigning Quotas per User The last step is assigning the disk quotas with the edquota command To configure the quota for a user as root in a shell prompt execute the command edquota username Perform this step for each user who needs a quota For example if a quota is enabled in etc
234. hentication Mode on the Security tab of the Server Settings preferences must be set to User for this option to work Also configure a Samba Password for the Samba User and confirm it by typing it again Even if you select to use encrypted passwords for Samba it is recommended that the Samba passwords for all users are different from their system passwords To edit an existing user select the user from the list and click Edit User To delete an existing Samba user select the user and click the Delete User button Deleting a Samba user does not delete the associated system user account The users are modified immediately after clicking the OK button 23 2 1 3 Adding a Share To create a Samba share click the Add button from the main Samba configuration window Basic Access Directory docs project Browse Share name docs project Description Shared Docs Project Basic Permissions Read only Read Write Cancel 2 OK Figure 23 5 Adding a Share The Basic tab configures the following options Chapter 23 Samba 181 Directory The directory to share via Samba The directory must exist before it can be entered here Share name The actual name of the share that is seen from remote machines By default it is the same value as Directory but can be configured Descriptions A brief description of the share Basic Permissions
235. hentication types refer to the Red Hat Enterprise Linux Reference Guide To start the graphical version of the Authentication Configuration Tool from the desktop select the Main Menu Button on the Panel gt System Settings gt Authentication or type the command system config authentication at a shell prompt for example in an XTerm or a GNOME terminal To start the text based version type the command authconfig as root at a shell prompt CB nscrtani After exiting the authentication program the changes made take effect immediately 27 1 User Information The User Information tab has several options To enable an option click the empty checkbox beside it To disable an option click the checkbox beside it to clear the checkbox Click OK to exit the program and apply the changes 224 Chapter 27 Authentication Configuration User Information Authentication NIS Hesiod NIS is the Network Information Service It is Hesiod allows a system administrator to publish commonly used on small to medium networks user and group information in DNS It is Z Enable NIS Support Configure NIS sometimes used in very large networks Enable Hesiod Suppo LDAP The Lightweight Directory Access Protocol is a Winbind standard way of searching a directory which can hold Winbind allows a system to retrieve information about users arbitrary data in a structured hierarchy LDAP is and to authenticate users by using information stored in a
236. hod page select Upgrade ex isting boot loader to upgrade the existing boot loader configuration while preserving the old entries Chapter 2 Kickstart Configurator 2 4 Partition Information Eile Help Basic Configuration Partition Information required Installation Method Clear Master Boot Record Boot Loader Options O Do not clear Master Boot Record Partition Information Remove all existing partitions Network Configuration O Remove existing Linux partitions Authentication O Preserve existing partitions Firewall Gonfiguraticg Initialize the disk label Display Configuration Do not initialize the disk label Hackeas Selacniori Device Mount Paint T F t Size MB Pre Installation Script Partition Number RAID RES oun Sica Post Installation Script Add esi Delete RAID Figure 2 4 Partition Information 31 Select whether or not to clear the Master Boot Record MBR Choose to remove all existing parti tions remove all existing Linux partitions or preserve existing partitions To initialize the disk label to the default for the architecture of the system for example msdos for x86 and gpt for Itanium select Initialize the disk label if you are installing on a brand new hard drive 2 4 1 Creating Partitions To create a partition click the Add button The Partition Options window shown in Figure 2 5 appears Choose the mount point file system type and partiti
237. 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 24 5 Static IP Address using DHCP The sample configuration file provided can be used as a starting point and custom configuration options can be added to it To copy it to the proper location use the following command cp usr share doc dhcp lt version number gt dhcpd conf sample etc dhcpd conf where lt version number gt is the DHCP version number For a complete list of option statements and what they do refer to the dhcp options man page 24 2 2 Lease Database On the DHCP server the file var lib dhcp dhcpd leases stores the DHCP client lease database This file should not be modified by hand DHCP lease information for each recently assigned IP address is automatically stored in the lease database The information includes the length of the lease to whom the IP address has been assigned the start and end dates for the lease and the MAC address of the network interface card that was used to retrieve the lease All times in the lease database are in Greenwich Mean Time GMT not local time The lease database is recreated from time to time so that it is not too large First all known leases are saved in a temporary lease database The dhcpd leases file is renamed dhcpd leases and the temporary lease database is written to dhcpd leases Chapter 24 Dynamic Hos
238. ick the corresponding Delete button To learn more about environment variables in the Apache HTTP Server refer to the following http httpd apache org docs 2 0 env html 25 2 4 Directories Use the Directories page in the Performance tab to configure options for specific directories This corresponds to the lt Directory gt directive Page Options Logging Environment Performance Default Directory Options f Edit ExecCGI FollowSymLinks Includes IncludesNOEXEC Indexes SymLinkslfOwnerMatch Directory Add f Edit 3 Delete T Help Cancel 2 OK Figure 25 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 202 Chapter 25 Apache HTTP Server Configuration 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 n
239. ies 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 Note If partitioning fails for any reason diagnostic messages appear on virtual console 3 poweroff optional Shut down and power off the system after the installation has successfully completed Normally during a manual installation anaconda displays a message and waits for the user to press a key before rebooting During a kickstart installation if no completion method is specified the reboot option is used as default The poweroff option is roughly equivalent to the shutdown p command Note The poweroff option is highly dependent on the system hardware in use Specifically cer tain hardware components such as the BIOS APM advanced power management and ACPI advanced configuration and power interface must be able to interact with the system kernel Contact your manufacturer for more information on you system s APM ACPI abilities For other completion methods refer to the halt reboot and shutdown kickstart options 14 Chapter 1 Kickstart Installations raid optional Assembles a software RAID device This command is of the form raid lt mntpoint gt level
240. ify 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 e To verify a package containing a particular file rpm Vf usr bin vim e To verify ALL installed packages rpm Va e To verify an installed package against an RPM package file rpm Vp foo 1 0 1 i386 rpm This command can be useful if you suspect that your RPM databases are corrupt If everything verified properly there is no output If there are any discrepancies they are displayed The format of the output is a string of eight characters a c denotes a configuration file and then the file name Each of the eight characters denotes the result of a comparison of one attribute of the file to the value of that attribute recorded in the RPM database A single period means the test passed The following characters denote failure of certain tests e 5 MDS checksum e s file size L symbolic link e T file modification time D device e U user G group e 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 15 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
241. ifying the configuration files directly refer to the Red Hat Enterprise Linux Refer ence Guide for information on their locations and contents 132 Chapter 18 Network Configuration Om Use the Red Hat Hardware Compatibility List http hardware redhat com hcl to determine if Red Hat Enterprise Linux supports your hardware device 18 1 Overview To configure a network connection with the Network Administration Tool perform the following steps 1 Add a network device associated with the physical hardware device 2 Add the physical hardware device to the hardware list if it does not already exist 3 Configure the hostname and DNS settings 4 Configure any hosts that cannot be looked up through DNS This chapter discusses each of these steps for each type of network connection 18 2 Establishing an Ethernet Connection To establish an Ethernet connection you need a network interface card NIC a network cable usually a CATS cable and a network to connect to Different networks are configured to use different network speeds make sure your NIC is compatible with the network to which you want to connect To add an Ethernet connection follow these steps 1 Click the Devices tab 2 Click the New button on the toolbar 3 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 Otherw
242. igure 8 6 Two Physical Volumes Created 8 2 3 Creating the LVM Volume Groups Once all the physical volumes are created the volume groups can be created 1 Click the LVM button to collect the physical volumes into volume groups A volume group is basically a collection of physical volumes You can have multiple logical volume groups but a physical volume can only be in one volume group Note There is overhead disk space reserved in the logical volume group The summation of the physical volumes may not equal the size of the volume group however the size of the logical volumes shown is correct Make LVM Volume Group Volume Group Name Physical Extent da2 8512 00 MB sdb 8640 00 MB Physical Volumes to Use Used Space 0 00 MB 0 0 Free Space 17152 00 MB 100 0 Total Space 17152 00 MB Logical Volumes Logical Volume Name Mount Point Size MB Edit Delete Cancel 2 OK Figure 8 7 Creating an LVM Volume Group Chapter 8 LVM Configuration 71 2 Change the Volume Group Name if desired 3 All logical volumes inside the volume group must be allocated in physical extent units By default the physical extent is set to 32 MB thus logical volume sizes must be divisible by 32 MBs If you enter a size that is not a unit of 32 MBs the installation program automatically selects the closest size in units of 32 MBs It is not r
243. igure 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 oN DAR WHY Exit the application and select to save your settings 196 Chapter 25 Apache HTTP Server Configuration 25 1 Basic Settings Use the Main tab to configure the basic server settings Main Virtual Hosts Server Performance Tuning Basic Setup Server Name Webmaster email address root localhost Available Addresses All available addresses on port 80 Add Edit Delete Set addresses for Apache to listen for requests on OK 3 Cancel T Heip Figure 25 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 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 set the server name to www example com while the server s real DNS name is foo example com Enter the email address of the person who maintains the Web server in the Webmaster email addres
244. igure 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 use the tool There are three ways to start the application From the desktop go to Applications the main menu on the panel gt System Settings gt Date amp Time From the desktop right click on the time in the toolbar and select Adjust Date and Time e Type the command system config date system config time or dateconfig at a shell prompt for example in an XTerm or a GNOME terminal 29 1 Time and Date Properties As shown in Figure 29 1 the first tabbed window that appears is for configuring the system date and time Date amp Time Network Time Protocol Time Zone Date 5 Time 4 January 2005 gt Current Time 12 08 10 Sun Mon Tue Wed Thu Fri Sat Hour 12 2 a Minute 7 E 2 3 4 5 6 7 8 Ta x t10 11 1 M AS Second 144 16 17 18 BRM 20 21 22 23 24 25 26 27 28 29 30 at T Heip 3 Cancel 2 OK Figure 29 1 Time and Date Properties 236 Chapter 29 Date and Time Configuration To change the date use the arrows to the left and right of the month to change the month use the arrows to the left and right of the year to change the year and click on the day of the week to change the day of the week Changes take place after the OK button is
245. iiniiis inii o E i NEE 315 41 7 Example Usage 41 8 Graphical Interfaces sscscsssievsscssscasassanestaiacveistoasssascievesstevnsisssavedacensveataiazseoasnses 41 9 Additional Resources 0 Introduction Welcome to the Red Hat Enterprise Linux System Administration Guide The Red Hat Enterprise Linux System Administration Guide contains information on how to customize your Red Hat Enterprise Linux system to fit your needs If you are looking for a step by step task oriented guide for configuring and customizing your system this is the manual for you This manual discusses many intermediate topics such as the following Setting up a network interface card NIC Performing a Kickstart installation Configuring Samba shares Managing your software with RPM Determining information about your system e Upgrading your kernel This manual is divided into the following main categories Installation Related Reference File Systems Reference Package Management Network Configuration System Configuration System Monitoring This guide assumes you have a basic understanding of your Red Hat Enterprise Linux system If you need help installing Red Hat Enterprise Linux refer to the Red Hat Enterprise Linux Installation Guide For more general information about system administration refer to the Red Hat Enterprise Linux Introduction to System Administration If you need more advanced documentation such a
246. ile ssh identity pub to the file ssh authorized_keys on the remote machine 4 If you are running GNOME skip to Section 21 3 4 4 Configuring ssh agent with GNOME If you are not running GNOME skip to Section 21 3 4 5 Configuring ssh agent 21 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 package contains the application 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 21 3 4 5 Configuring ssh agent To save your passphrase during your GNOME session follow the following steps 1 You will need to have the package openssh askpass gnome installed you can use the com mand rpm q openssh askpass gnome to determine if it is installed or not If it is not in stalled install it from your Red Hat Enterprise Linux CD ROM set from a Red Hat FTP mirror site or using Red Hat Network 2 Select Main Menu Button on the Panel gt Preferences gt More Preferences gt Sessions and click on the Startup Programs tab Click Add and enter usr bin ssh add in the Startup Command text area Set it a priority to a number higher than any exis
247. ile you must specify the full path of the file for example 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 Query Options e i displays package information including name description release size build date install date vendor and other miscellaneous information e 1 displays the list of files that the package contains e s displays the state of all the files in the package e 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 add v to the command to display the lists in a familiar 1s 1 format Chapter 15 Package Management with RPM 117 15 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 Verify Options listed for querying to spec
248. ing Target Architecture specifies which specific hardware architecture distribution is used during installation Choosing Reboot system after installation reboots your system automatically after the installation is finished Kickstart installations are performed in graphical mode by default To override this default and use text mode instead select the Perform installation in text mode option You can perform a kickstart installation in interactive mode This means that the installation program uses all the options pre configured in the kickstart file but it allows you to preview the options in each screen before continuing to the next screen To continue to the next screen click the Next button after you have approved the settings or change them before continuing the installation To select this type of installation select the Perform installation in interactive mode option Chapter 2 Kickstart Configurator 29 2 2 Installation Method Eile Help Basic Configuration Installation Method required Perform new installation Boot Loader Options O Upgrade an existing installation Partition Information Choose the Installation Method Network Configuration CD ROM Authentication ONFS Firewall Configuration O FTP Display Configuration O HTTP Package Selection O Hard Drive Pre Installation Script Post Installation Script Figure 2 2 Installation Method The Installation Method screen allows you to choose whether to
249. ing 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 migrate from ext2 to ext3 and gain the benefits of a robust journaling file system without reformatting Refer to Section 6 3 Converting to an ext3 File System for more on how to perform this task The following sections walk you through the steps for creating and tuning ext3 partitions For ext2 partitions skip the partitioning and formating sections below and go directly to Section 6 3 Converting to an ext3 File System 6 2 Creating an ext3 File System After installation it is sometimes necessary to create a new ext3 file system For example if you add a new disk drive to the system you may want to partition the drive and use the ext3 file system 60 Chapter 6 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 the etc fstab file 6 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
250. ion samba server 3 Cancel 2 OK Figure 23 2 Configuring Basic Server Settings On the Basic tab specify which workgroup the computer should be in as well as a brief description of the computer They correspond to the workgroup and server string options in smb conf Basic Security Authentication Mode User Authentication Server Kerberos Realm Encrypt Passwords Yes z Guest Account No guest account z Cancel 2 OK Figure 23 3 Configuring Security Server Settings The Security tab contains the following options Authentication Mode This corresponds to the security option Select one of the following types of authentication ADS The Samba server acts as a domain member in an Active Directory Domain ADS realm For this option Kerberos must be installed and configured on the server and Samba must become a member of the ADS realm using the net utility which is part of the samba client Chapter 23 Samba 179 package Refer to the net man page for details This option does not configure Samba to be an ADS Controller Specify the realm of the Kerberos server in the Kerberos Realm field Note The Kerberos Realm field must be supplied in all uppercase letters such as EXAMPLE COM Use of your Samba server as a domain member in an ADS realm assumes proper configuration of Kerberos including the etc krb5
251. ion of users against an SMB server typically a Samba or Windows server SMB authentication support does not know about home directories UIDs or shells If you enable SMB you must make users accounts known to the workstation by enabling LDAP NIS or Hesiod or by using the usr sbin useradd command to make their ac counts known to the workstation To use this option you must have the pam_smb package installed smbservers The name of the server s to use for SMB authentication To specify more than one server separate the names with commas smbworkgroup The name of the workgroup for the SMB servers Chapter 1 Kickstart Installations 5 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 GRUB boot loader should be installed This option is required for both instal lations and upgrades For upgrades if GRUB is not the current boot loader the boot loader is changed to GRUB To preserve other boot loaders use boot loader upgrade append Specifies kernel parameters To specify multiple parameters separate them with spaces For example bootloader location mbr append hdd ide scsi ide nodma driveorder Specify which drive is first in
252. ion server andriusb 83MB 0 bytes O 18358 clock applet andriusb 20 4 MB 0 bytes O 18436 dbus daemon 1 andriusb 14 0 MB 0 bytes O 18348 dbus launch andriusb 4 3MB 0 bytes o 18347 eggcups andriusb 39 9 MB 0 bytes o 18410 gam_server andriusb 3 0MB 0 bytes O 18366 gcontd 2 andriusb 12 0 MB 0 bytes O 18353 gnome keyting daemon andriusb 3 3MB 0 bytes O 18356 gnome keyring daemon andriusb 3 9MB 0 bytes 0 3434 L E gnome panel andriusb 24 4 MB 401K o 18404 gnome settings daemon andriusb 19 4 MB 0 bytes O 18360 8 gnome system monitor andriusb 23 1 MB 1 4 MB o 18440 gnome vis daemon andriusb 21 0 MB 0 bytes o 1821 gnome volume manager andriusb 19 0 MB 0 bytes o 18408 mapping daemon andriusb 29MB 0 bytes 0 1829 metacity andriusb 14 4 MB _0 bytes o 18399 ial More Info gt gt End Process Figure 40 1 GNOME System Monitor 40 2 Memory Usage 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 used free shared buffers cached Mem 645712 549720 95992 0 176248 224452 buffers cache 149020 496692 Swap 1310712 0 1310712 The command free m shows the same information in megabytes which are easier to read total used free shared buffers cached Mem 630 536 93 0 172 219 buffers cache 145 485 Swap 1279 0 1279 If prefer a graphical interface for free you can use the GNOME Syste
253. ioning you can either f YV Hard Di accept the current partition gonna settings click Next or modify devi sda the setup using the manual dev sdal boot ext3 4 102 1 4 partitioning tool dev sda2 VolGroup00 LVMPV 8574 14 1106 V dev sdb Ifyou are manually partitioning dev sdb1 VolGroup00 LVMPV v 8676 1 1106 your system you can see your current hard drive s and Kl partitions displayed below Use Hide RAID device LVM Volume Group members WBHide Help Release Notes lt Back gt Next Figure 8 1 Automatic LVM Configuration With Two SCSI Drives Note If enabling quotas are of interest to you it may be best to modify the automatic configuration to include other mount points such as home or var so that each file system has its own independent quota configuration limits In most cases the default automatic LVM partitioning is sufficient but advanced implementations could warrant modification or manual configuration of the LVM partition tables f Note If you anticipate future memory upgrades leaving some free space in the volume group would al low for easy future expansion of the swap space logical volume on the system in which case the automatic LVM configuration should be modified to leave available space for future growth 8 2 Manual LVM Partitioning The following section explains how to manually configure LVM for
254. is already mounted while it is being transitioned the journal is visible as the file journal in the root directory of the file system If the file system is not mounted the journal is hidden and does not appear in the file system at all Note A default installation of Red Hat Enterprise Linux uses ext3 for all file systems To convert an ext2 file system to ext3 log in as root and type sbin tune2fs j lt file_system gt where lt file_system gt is an appropriate LVM file system A valid LVM2 file system could be one of two types of entries e A mapped device A logical volume in a volume group for example dev mapper VolGroup00 LogVol02 e A static device A traditional storage volume for example dev hdbx where hdb is a storage device name and X is the partition number Issue the df command to display mounted file systems For the remainder of this section the sample commands use the following value dev mapper VolGroup00 LogVol02 After doing this be certain to change the partition type from ext2 to ext3 in the etc fstab file If you are transitioning your root file system you must use an initrd image or RAM disk to boot To create this run the mkinitrd program For information on using the mkinitrd command type man mkinitrd Also make sure your GRUB configuration loads the initrd If you fail to make this change the system still boots but the file system is mounted as ext2 instead of ext3 Chap
255. ise select Other Ethernet Card to add the hardware device Note The installation program detects supported Ethernet devices and prompts you to configure them If you configured any Ethernet devices during the installation they are displayed in the hardware list on the Hardware tab 5 If you selected Other Ethernet Card the Select Ethernet Adapter window appears Select the manufacturer and model of the Ethernet card Select the device name If this is the system s first Ethernet card select eth0 as the device name if this is the second Ethernet card select eth1 and so on The Network Administration Tool also allows you to configure the resources for the NIC Click Forward to continue 6 In the Configure Network Settings window as shown in Figure 18 2 choose between DHCP and a static IP address If the device receives a different IP address each time the network is started do not specify a hostname Click Forward to continue 7 Click Apply on the Create Ethernet Device page Chapter 18 Network Configuration 133 Configure Network Settings Automatically obtain IP address settings with dhcp Y DHCP Settings Hostname optional v Automatically obtain DNS information from provider CO Statically set IP addresses Manual IP Address Settings Address Subnet Mask Default Gateway Address 3 Cancel lt Back D Eorward Fi
256. isk 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 For a detailed example of raid in action refer to Section 1 4 1 Advanced Partitioning Example reboot optional Reboot after the installation is successfully completed no arguments Normally during a manual installation anaconda displays a message and waits for the user to press a key before rebooting The reboot option is roughly equivalent to the shutdown r command Chapter 1 Kickstart Installations 15 Note Use of the reboot option may result in an endless installation loop depending on the installation media and method The reboot option is the default completion method if no other methods are explicitly specified in the kickstart file For other completion methods refer to the halt poweroff and shutdown kickstart options rootpw 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 selinux optional Sets the system s SELinux mode to one of the following arguments enforcing Enables SELinux with the default targeted policy being enforced l Note If the selinux option is not present in the kic
257. ist are accepted by the system For example if eth1 only receives connections from internal system you might want to allow connections from it If a service is selected in the Trusted services list connections for the service are accepted and processed by the system In the Other ports text field list any additional ports that should be opened for remote access Use the following format port protocol For example to allow IMAP access through the firewall specify imap tcp Specify numeric ports can also be specified to allow UDP packets on port 1234 through the firewall enter 1234 udp To specify multiple ports separate them with commas 2 7 1 SELinux Configuration Although configuration for SELinux is not specified in the Kickstart Configurator kickstart enables SELinux in enforcing mode by default if the sel inux parameter is omitted from the kickstart file 2 8 Display Configuration If you are installing the X Window System you can configure it during the kickstart installation by checking the Configure the X Window System option on the Display Configuration window as shown in Figure 2 11 If this option is not chosen the X configuration options are disabled and the skipx option is written to the kickstart file Chapter 2 Kickstart Configurator 37 2 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 co
258. it grow to fill all available space on the hard disk If you make more than one partition growable they share the available free space on the disk 6 Select Force to be a primary partition if you want the partition to be a primary partition A primary partition is one of the first four partitions on the hard drive If unselected the partition is created as a logical partition If other operating systems are already on the system unselecting this option should be considered For more information on primary versus logical extended partitions refer to the appendix section of the Red Hat Enterprise Linux Installation Guide 7 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 par titions do not have to be RAID partitions For example you can configure only the boot partition as a software RAID device leaving the root partition home and swap as regular file systems Figure 10 4 shows successfully allocated space for the RAID 1 configuration for boot which is now ready for RAID device and mount point creation 80 Chapter 10 Software RAID Configuration Disk Setup Drive dev sda 8676 MB Model IBM PSG ST39103LC 1 Free 8573 MB Choose where you would like Red Hat Enterprise Linux AS to _ Drive Mlev sdb 8676 MB Model IBM PSG ST39204LC 1 Free be installed 8573 MB Ifyou do not know how to
259. it is sometimes necessary to explicitly force the loading of a module at boot time Red Hat Enterprise Linux checks for the existence of the etc rc modules file at boot time which contains various commands to load modules The rc modules should be used and not rc local because rc modules is executed earlier in the boot process For example the following commands configure loading of the foo module at boot time as root echo modprobe foo gt gt etc rc modules chmod x etc rc modules Om This approach is not necessary for network and SCSI interfaces because they have their own specific mechanisms 38 3 Additional Resources For more information on kernel modules and their utilities refer to the following resources 38 3 1 Installed Documentation lsmod man page description and explanation of its output e insmod man page description and list of command line options modprobe man page description and list of command line options rmmod man page description and list of command line options e modinfo man page description and list of command line options e usr share doc kernel doc lt version gt Documentation kbuild modules txt how to compile and use kernel modules 296 Chapter 38 Kernel Modules 38 3 2 Useful Websites http www redhat com mirrors LDP HOWTO Module HOWTO index html Linux Loadable Kernel Module HOWTO from the Linux Documentation Project Chapter 39 Mail T
260. iving the one physical device more than one IP address For example you can configure an eth device and an eth1 1 device For details refer to Section 18 11 Device Aliases 134 Chapter 18 Network Configuration 18 3 Establishing an ISDN Connection An ISDN connection is an Internet connection established with a ISDN modem card through a special phone line installed by the phone company ISDN connections are popular in Europe To add an ISDN connection follow these steps 1 Click the Devices tab 2 Click the New button on the toolbar 3 Select ISDN connection from the Device Type list and click Forward 4 Select the ISDN adapter from the pulldown menu Then configure the resources and D channel protocol for the adapter Click Forward to continue Select ISDN Adapter T ISDN Adapters ACER P10 El Resource D Channel Protocol IRQ 5 2l Euro ISDN EDSS1 MEM O 1TR6 10 0x300 Cancel lt Back D gt Eoward Figure 18 4 ISDN Settings 5 If your Internet Service Provider ISP is in the pre configured list select it Otherwise enter the required information about your ISP account If you do not know the values contact your ISP Click Forward 6 In the IP Settings window select the Encapsulation Mode and whether to obtain an IP address automatically or to set one statically Click Forward when finished 7 On the Create Dialup Connection page click Apply After c
261. j Hide RAID device LVM Volume Group members Buide Help Release Notes lt Back BP Next Figure 8 2 Two Blank Drives Ready For Configuration A waming The boot partition cannot reside on an LVM volume group because the GRUB boot loader cannot read it Select New Select boot from the Mount Point pulldown menu Select ext3 from the File System Type pulldown menu Select only the sda checkbox from the Allowable Drives area Leave 100 the default in the Size MB menu Leave the Fixed size the default radio button selected in the Additional Size Options area y Aun fF WN Select Force to be a primary partition to make the partition be a primary partition A primary partition is one of the first four partitions on the hard drive If unselected the partition is created as a logical partition If other operating systems are already on the system unselecting this op tion should be considered For more information on primary versus logical extended partitions refer to the appendix section of the Red Hat Enterprise Linux Installation Guide Refer to Figure 8 3 to verify your inputted values 68 Chapter 8 LVM Configuration Mount Point boot File System Type ext3 x sda 8676 MB IBM PSG ST39103LC Allowable Drives I sdb 8676 MB IBM PSG ST39204LC Size MB 100 aj Additional Size Options Fixed size Fill all space up to MB 1 O Fill to maxi
262. kages installed on this system in my System Profile Below is a list of packages present on your system that RPM knows about Step 3 Register a System Profile Packages RPM information is important to determine what updated software packages are relevant Package Name version Release v 4Suite 0 11 1 14 Z GConf 1 0 9 12 GConf2 2 2 1 1 M Glide3 2001052 25 MAKEDEV 3 3 6 1 V ORBit 0 5 17 10 4 ORBit2 2 6 2 1 By default all packages that RPM knows about will be included in your System Profile Uncheck any packages which you do not want to be included Cancel Back D Forward Figure 17 3 Registering with RHN After registering use one of the following methods to start receiving updates 127 Select Applications the main menu on the panel gt System Tools gt Red Hat Network on your desktop Execute the command up2date from a shell prompt Use the RHN website at https rhn redhat com For more detailed instructions refer to the documentation available at http www redhat com docs manuals RHNetwork 0 Red Hat Enterprise Linux includes the Red Hat Network Alert Notification Tool a convenient panel icon that displays visible alerts when there is an update for your Red Hat Enterprise Linux system 128 Chapter 17 Red Hat Network IV Network Related Configuration After
263. key and certificate so that the secure server can use them Use the following two commands to move and rename your key and certificate files mv etc httpd conf httpsd key etc httpd conf ssl key server key mv etc httpd conf httpsd crt etc httpd conf ssl crt server crt Then start your secure server with the command sbin service httpd start You are prompted to enter your passphrase After you type it in and press Enter the server starts Chapter 26 Apache HTTP Secure Server Configuration 215 26 5 Types of Certificates If you installed your secure server from the RPM package provided by Red Hat a random key and a test certificate are generated and put into the appropriate directories Before you begin using your secure server however you must generate your own key and obtain a certificate which correctly identifies your server You need a key and a certificate to operate your secure server which means that you can either gen erate a self signed certificate or purchase a CA signed certificate from a CA What are the differences between the two A CA signed certificate provides two important capabilities for your server Browsers usually automatically recognize the certificate and allow a secure connection to be made without prompting the user When a CA issues a signed certificate they are guaranteeing the identity of the organization that is providing the webpages to the browser If your secure server is bein
264. kstart file SELinux is enabled and set to enforcing by default permissive Outputs warnings only based on the SELinux policy but does not actually enforce the pol icy disabled Disables SELinux completely on the system For complete information regarding SELinux for Red Hat Enterprise Linux refer to the Red Hat SELinux Guide shutdown optional Shut down the system after the installation has successfully completed During a kickstart instal lation if no completion method is specified the reboot option is used as default The shutdown option is roughly equivalent to the shutdown command For other completion methods refer to the halt poweroff and reboot kickstart options skipx optional If present X is not configured on the installed system 16 Chapter 1 Kickstart Installations text optional Perform the kickstart installation in text mode Kickstart installations are performed in graphical mode by default timezone required Sets the system time zone to lt timezone gt which may be any of the time zones listed by timeconfig timezone utc lt timezone gt Kee 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 de
265. l Host IP based Virtual Host or Name based Virtual Host Default Virtual Host You should only configure one default virtual host remember that there is one setup by default The default virtual host settings are used when the requested IP address is not explicitly listed in another virtual host If there is no default virtual host defined the main server settings are used IP based Virtual Host If you choose IP based Virtual Host a window appears to configure the lt VirtualHost gt di rective based on the IP address of the server Specify this IP address in the IP address field To specify multiple IP addresses separate each IP address with spaces To specify a port use the syntax IP Address Port Use colon asterisk to configure all ports for the IP address Specify the host name for the virtual host in the Server Host Name field 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 multiple IP addresses separate each IP address with spaces To specify a port use the syntax IP Address Port Use colon asterisk 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 NameVirtu
266. l 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 Multiple commands 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 278 Chapter 35 Automated Tasks If the set of commands or script tries to display information to standard out the output is emailed to the user Use the command atq to view pending jobs Refer to Section 35 2 3 Viewing Pending Jobs for more information Usage of the at command can be restricted For more information refer to Section 35 2 5 Controlling Access to At and Batch for details 35 2 2 Configuring Batch Jobs To execute a one time task when the load average is below 0 8 use the batch command After typing the batch command the at gt prompt is displayed Type the command to execute press Enter and type Ctrl D Multiple commands can be specified by typing each command followed by the
267. lations Verena Fuehrer German translations Kiyoto Hashida Japanese translations N Jayaradha Tamil translations Michelle Jiyeen Kim Korean translations Yelitza Louze Spanish translations Noriko Mizumoto Japanese translations 334 Ankitkumar Rameshchandra Patel Gujarati translations Rajesh Ranjan Hindi translations Nadine Richter German translations Audrey Simons French translations Francesco Valente Italian translations Sarah Wang Simplified Chinese translations Ben Hung Pin Wu Traditional Chinese translations Tongjie Tony Fu Simplified Chinese Translations Manuel Ospina Spanish Translations
268. le includes some examples dhcpd leases man page Explains how to configure the DHCP leases file includes some ex amples dhcp options man page Explains the syntax for declaring DHCP options in dhcpd conf includes some examples dhcrelay man page Explains the DHCP Relay Agent and its configuration options e usr share doc dhcp lt version gt Contains sample files README files and release notes for the specific version of the DHCP service 194 Chapter 24 Dynamic Host Configuration Protocol DHCP Chapter 25 Apache HTTP Server Configuration Red Hat Enterprise Linux provides version 2 0 of the Apache HTTP Server If you want to migrate an existing configuration file by hand refer to the migration guide at usr share doc httpd lt ver gt migration html or the Red Hat Enterprise Linux Reference Guide for details If you configured the Apache HTTP Server with the HTTP Configuration Tool in previous versions of Red Hat Enterprise Linux and then performed an upgrade you can use the HTTP Configuration Tool to migrate the configuration file to the new format for version 2 0 Start the HTTP Configura tion Tool make any changes to the configuration and save it The configuration file saved will be compatible with version 2 0 The httpd and system config httpd RPM packages need to be installed to use the HTTP Con figuration Tool It also requires the X Window System and root access To start the applicati
269. le Help arg xX New Edit Copy Delete Activate Deactivate Devices Hardware IPsec DNS Hosts You may configure network devices associated with gil 3 5 physical hardware here Multiple logical devices can be s associated with a single piece of hardware Profile Status Nickname AESA Figure 18 13 Wireless Device Be sure to select File gt Save to save the changes After adding the wireless device you can edit its configuration by selecting the device from the device list and clicking Edit For example you can configure the device to activate at boot time When the device is added it is not activated immediately as seen by its Inactive status To activate the device select it from the device list and click the Activate button If the system is configured to activate the device when the computer starts the default this step does not have to be performed again 18 8 Managing DNS Settings The DNS tab allows you to configure the system s hostname domain name servers and search do main Name servers are used to look up other hosts on the network If the DNS server names are retrieved from DHCP or PPPoE or retrieved from the ISP do not add primary secondary or tertiary DNS servers If the hostname is retrieved dynamically from DHCP or PPPoE or retrieved from the ISP do not change it File Profile Help B B New Edit Copy Delete
270. le exists the existing sample file is automatically deleted Thus if the existing sample file is needed it must be backed up along with the executable used to create it before replacing the executable with a new version Refer to Section 41 4 Saving Data for details on how to backup the sample file 41 5 1 Using opreport The opreport tool provides an overview of all the executables being profiled The following is part of an example output Profiling through timer interrupt TIMER 0 samples S 25926 97 5212 no vmlinux 359 1 3504 pi 65 0 2445 Xorg 62 0 2332 libvte so 4 4 0 56 0 2106 libc 2 3 4 so 34 0 1279 libglib 2 0 s0 0 400 7 19 0 0715 libXft so 2 1 2 17 0 0639 bash 8 0 0301 1d 2 3 4 so 8 0 0301 libgdk x11 2 0 s0 0 400 13 6 0 0226 libgobject 2 0 so0 0 400 7 5 0 0188 oprofiled 4 0 0150 libpthread 2 3 4 so 4 0 0150 libgtk x11 2 0 s0 0 400 13 3 0 0113 libXrender so 1 2 2 3 0 0113 du 1 0 0038 libcrypto so 0 9 7a 1 0 0038 libpam so 0 77 1 0 0038 libtermcap so 2 0 8 1 0 0038 libxX11 so 6 2 1 0 0038 libgthread 2 0 so0 0 400 7 1 0 0038 libwnck 1 so 4 9 0 Each executable is listed on its own line The first column is the number of samples recorded for the executable The second column is the percentage of samples relative to the total number of samples The third column is the name of the executable Refer to the opreport man page for a list of available command line options such as the r option used to sort the output from
271. linear RAID the chunks are allocated sequentially from one member drive going to the next drive only when the first is completely filled This grouping provides no performance benefit as it is unlikely that any I O operations will be split between member drives Linear RAID also offers no redundancy and in fact decreases reliability if any one member drive fails the entire array cannot be used The capacity is the total of all member disks 3 Parity information is calculated based on the contents of the rest of the member disks in the array This information can then be used to reconstruct data when one disk in the array fails The reconstructed data can then be used to satisfy I O requests to the failed disk before it is replaced and to repopulate the failed disk after it has been replaced 4 RAID level 4 takes up the same amount of space as RAID level 5 but level 5 has more advantages For this reason level 4 is not supported 76 Chapter 9 Redundant Array of Independent Disks RAID Chapter 10 Software RAID Configuration Software RAID can be configured during the graphical installation process the text based installation process or during a kickstart installation This chapter discusses how to configure software RAID during installation using the Disk Druid interface Read Chapter 9 Redundant Array of Independent Disks RAID first to learn about RAID the differ ences between hardware and software RAID and the differe
272. listens on all ports for the services it manages When a connection request arrives for one of its managed services xinetd starts up the appropriate server for that service The configuration file for xinetd is etc xinetd conf but the file only contains a few defaults and an instruction to include the etc xinetd d directory To enable or disable an xinetd service edit its configuration file in the etc xinetd d directory If the disable attribute is set to yes the service is disabled If the disable attribute is set to no the service is enabled You can edit any of the xinetd configuration files or change its enabled status using the Services Configuration Tool ntsysv or chkconfig For a list of network services controlled by xinetd review the contents of the etc xinetd d directory with the command 1s etc xinetd d Chapter 20 Controlling Access to Services 159 20 3 Services Configuration Tool The Services Configuration Tool is a graphical application developed by Red Hat to configure which SysV services in the etc rc d init d directory are started at boot time for runlevels 3 4 and 5 and which xinetd services are enabled It also allows you to start stop and restart SysV services as well as restart xinetd To start the Services Configuration Tool from the desktop go to the Main Menu Button on the Panel gt System Settings gt Server Settings gt Services or type the command system config services at a shell prompt for
273. lor depth and resolution that is compatible with the video card and monitor for the system Eile Help Basic Configuration Display Configuration Installation Method Configure the X Window System Boot Loader Options General Video Card Monitor Partition Information Color Depth a Resolutian Network Configuration 8 x 640x480 v Authentication Default Desktop GNOME KDE Firewall Configuration Display Configuration C Start the X Window System on boot Package Selection On first boot Setup Agent is Disabled T Pre Installation Script Post Installation Script Figure 2 11 X Configuration General If you are installing both the GNOME and KDE desktops you must choose which desktop should be the default If only one desktop is to be installed be sure to choose it Once the system is installed users can choose which desktop they want to be their default Next choose whether to start the X Window System when the system is booted This option starts the system in runlevel 5 with the graphical login screen After the system is installed this can be changed by modifying the etc inittab configuration file Also select whether to start the Setup Agent the first time the system is rebooted It is disabled by default but the setting can be changed to enabled or enabled in reconfiguration mode Reconfigu ration mode enables the language mouse keyboard roo
274. lose to return to the main window Log Files Alerts Warnings Log Files x Configure the path and filename for each log file displayed Log File Location i Add Boot Log var log boot log Edit Cron Li var log cron cia ae Log alten Delete Mail Log var log maillog MySQL Server Log var log mysqld log News Log var log spooler RPM Packages varflog rpmpkgs X Refresh Rate Refresh log file every 30 seconds Figure 36 2 Log File Locations Chapter 36 Log Files 283 36 3 Adding a Log File To add a log file to the list select Edit gt Preferences and click the Add button in the Log Files tab X Specify a new log file location Name Custom Log Description A description of my custom log Location jyar log custom log Cancel 2 OK Figure 36 3 Adding a Log File Provide a name description and the location of the log file to add After clicking OK the file is immediately added to the viewing area if the file exists 36 4 Examining Log Files Log Viewer can be configured to display an alert icon beside lines that contain key alert words and a warning icon beside lines that contain key warning words To add alerts words select Edit gt Preferences from the pulldown menu and click on the Alerts tab Click the Add button to add an alert word To delete an alert word select the word f
275. lso called a dial up account is required To add a modem connection follow these steps 1 Click the Devices tab 2 Click the New button on the toolbar 3 Select Modem connection from the Device Type list and click Forward 4 If there is a modem already configured in the hardware list on the Hardware tab the Network Administration Tool assumes you want to use it to establish a modem connection If there are no modems already configured it tries to detect any modems in the system This probe might take a while If a modem is not found a message is displayed to warn you that the settings shown are not values found from the probe 5 After probing the window in Figure 18 6 appears Select Modem oe Modem Properties Modem Device devjttySo x Baud Rate 57600 lt Elow Control Hardware CRTSCTS bd Modem Volume Off X Use touch tone dialing Cancel lt Back D Eoward Figure 18 6 Modem Settings 136 Chapter 18 Network Configuration 6 Configure the modem device baud rate flow control and modem volume If you do not know these values accept the defaults if the modem was probed successfully If you do not have touch tone dialing uncheck the corresponding checkbox Click Forward 7 If your ISP is in the pre configured list select it Otherwise enter the required information about your ISP account If you do not know these values contact your IS
276. lt level gt device lt mddevice gt lt partitions gt lt mntpoint gt Location where the RAID file system is mounted If it is the RAID level must be 1 unless a boot partition boot is present If a boot partition is present the boot partition must be level 1 and the root partition can be any of the available types The lt partitions gt which denotes that multiple partitions can be listed lists the RAID identifiers to add to the RAID array level RAID level to use 0 1 or 5 device Name of the RAID device to use such as mdO or md1 RAID devices range from md0 to md7 and each may only be used once spares Specifies the number of spare drives allocated for the RAID array Spare drives are used to rebuild the array in case of drive failure fstype Sets the file system type for the RAID array Valid values are ext2 ext3 swap and vfat noformat Use an existing RAID device and do not format the RAID array useexisting Use an existing RAID device and reformat it The following example shows how to create a RAID level 1 partition for and a RAID level 5 for usr assuming there are three SCSI disks on the 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 ond
277. lue to set text field Click OK to add it to the list The Set for CGI Scripts section configures the Set Env directive Use the Pass to CGI Scripts section to pass the value of an environment variable when the server is first started to CGI scripts To see this environment variable type the command env at a shell prompt Click the Add button inside the Pass to CGI Scripts section and enter the name of the environment variable in the resulting dialog box Click OK to add it to the list The Pass to CGI Scripts section configures the PassEnv directive Page Options Logging Environment Performance Set for CGI Scripts Environment Variable Value Add Pass to CGI Scripts Unset for CGI Scripts Add Se gf Edit z Delete T Help 3 Cancel 2 OK Figure 25 5 Environment Variables 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 Chapter 25 Apache HTTP Server Configuration 201 name of the environment variable to unset Click OK to add it to the list This corresponds to the UnsetEnv directive To edit any of these environment values select it from the list and click the corresponding Edit button To delete any entry from the list select it and cl
278. lus to view available Samba shares on your network Select Main Menu Button on the Panel gt Network Servers to view a list of Samba workgroups on your network You can also type smb in the Location bar of Nautilus to view the workgroups As shown in Figure 23 6 an icon appears for each available SMB workgroup on the network Ele Edt View Go Bookmarks Help q P 404 8 O Back Foward Up Stop Reload Home Location smb y 00 View as Icons n am ma a af Oe ala ARTSTUFF MINE MYGROUP REDHAT a Hf WORKGROUP WORKGROUP selected 0 bytes Figure 23 6 SMB Workgroups in Nautilus Double click one of the workgroup icons to view a list of computers within the workgroup 184 Chapter 23 Samba file Edit View Go Bookmarks Help I gt AGAJ A DB Back Foward Up Stop Reload Home Location smb workgroup fa View as icons H 4 2 i FALCON PIGDOG PINKY YETI WORKGROUP selected 0 bytes Figure 23 7 SMB Machines in Nautilus As you can see from Figure 23 7 there is an icon for each machine within the workgroup Double click on an icon to view the Samba shares on the machine If a username and password combination is required you are prompted for them Alternately you can also specify the Samba server and sharename in the Location bar for Nautilus using the following syntax replace lt servername gt and lt sharename gt with the appropriate values
279. lved dependency output similar to the following is displayed error Failed dependencies bar so 2 is needed by foo 1 0 1 Suggested resolutions bar 2 0 20 3 1386 rpm If you are installing a package from the Red Hat Enterprise Linux CD ROM set it usually suggest the package s needed to resolve the dependency Find the suggested package s on the Red Hat Enterprise Linux CD ROMs or from the Red Hat FTP site or mirror and add it to the command rpm ivh foo 1 0 1 i386 rpm bar 2 0 20 3 1386 rpm If installation of both packages is successful output similar to the following is displayed Preparing SEA AA AAR AE RAT AE FE AE FE E AE AEE AE EAE AEA AE AE EE aE EAE aE aE HE E 1005 1 fo00 TRAE AEA AAR AE AE AE E AEE AEA AE AEE E ARE AE E AE aE ARE aE EEE aE EAE EAE AE 503 2 bar HARA AE AE AE AE AE AE AE AE AE AE E AEA AE AEE AE AEE AE AE AE AEE AE aE EAE aE aE EEE EAE AE 100 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 option 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 is displayed bar 2 0 20 3 i1386 rpm To force the installation anyway which is not recommended since the package may not run correctly use the nodeps option 15 2 3 Uninstalling
280. ly use ntsysv chkconfig or the Services Configuration Tool to enable it at runtime Refer to Chapter 20 Controlling Access to Services for details The pam_smbpass PAM module can be used to sync users Samba passwords with their system passwords when the passwd command is used If a user invokes the passwd command the password he uses to log in to the Red Hat Enterprise Linux system as well as the password he must provide to connect to a Samba share are changed To enable this feature add the following line to etc pam d system auth below the pam_crack1lib so invocation password required lib security pam_smbpass so nullok use_authtok try _first_pass 23 2 4 Starting and Stopping the Server On the server that is sharing directories via Samba the smb service must be running View the status of the Samba daemon with the following command Chapter 23 Samba 183 sbin service smb status Start the daemon with the following command sbin service smb start Stop the daemon with the following command sbin service smb stop To start the smb service at boot time use the command sbin chkconfig level 345 smb on You can also use chkconf ig ntsysv or the Services Configuration Tool to configure which services start at boot time Refer to Chapter 20 Controlling Access to Services for details om To view active connections to the system execute the command smbstatus 23 3 Connecting to a Samba Share You can use Nauti
281. ly created configuration The boot partition resides on its own non LVM partition In the following example it is the first partition on the first drive dev sda1 Bootable partitions cannot reside on LVM logical volumes A single LVM volume group VolGroup00 is created which spans all selected drives and all remaining space available In the following example the remainder of the first drive dev sda2 and the entire second drive dev sdb1 are allocated to the volume group Two LVM logical volumes LogVo100 and LogVo101 are created from the newly created spanned volume group In the following example the recommended swap space is automatically calculated and assigned to LogVo101 and the remainder is allocated to the root file system LogVol00 66 Chapter 8 LVM Configuration Drive Mdev sda 8676 MB Model IBM PSG ST39103LC Disk Setup ine i Drive dev sdb 8676 MB Model IBM PSG ST39204LC sdb Choose where you would like Red Hat Enterprise Linux AS to 8675 MB be installed New Edit Delete Reset RAID LVM If you do not know how to partition your system or if you Device RDN na Type Foma Sry Start End need help with using the manual partitioning tools refer Y LVM Volume Groups to the product documentation Y VolGroup00 17152 g LogVol00 ext3 v 15872 If you used automatic LogVol01 isa 1280 partit
282. m Monitor To start it from the desktop go to Applications the main menu on the panel gt System Tools gt System Monitor or type gnome system monitor at a shell prompt such as an XTerm Choose the System Monitor tab 304 Chapter 40 Gathering System Information File Edit View Help Process Listing Resource Monitor CPU History CPUI 16 0 Memory and Swap History Used memory 203MB of 631 MB Used swap Obytes of 1 2 GB Devices Directory Type Total Used Idev sdal boot ext3 983MB 91MB E 9 Name so none dev shm tmpfs 315 MB 0 bytes 0 dev mapper VolGroup00 LogVol00 1 ext 111GB 60GB MEE In Figure 40 2 GNOME System Monitor 40 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 mapper VolGroup00 LogVol00 11675568 6272120 4810348 57 dev sdal 100691 9281 86211 10 boot none 322856 0 322856 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 Mounted on dev mapper VolGroup
283. m 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 are 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 this should be read as one continuous line network bootproto static ip 10 0 2 15 netmask 255 255 255 0 gateway 10 0 2 254 nameserver 10 0 2 1 If you use the static method be aware of the following two restrictions All static networking configuration information must be specified on one line you cannot wrap lines using a backslash for example You can only specify one nameserver here However you can use the kickstart file s post section described in Section 1 7 Post installation Script to add more name servers if needed device Used to select a specific Ethernet device for installation Note that using device is not effective u
284. mand replacing lt name gt with a unique descriptive name for the current session opcontrol save lt name gt The directory var lib oprofile samples name is created and the current sample files are copied to it 41 5 Analyzing the Data Periodically the OProfile daemon oprofiled collects the samples and writes them to the var lib oprofile samples directory Before reading the data make sure all data has been written to this directory by executing the following command as root opcontrol dump Each sample file name is based on the name of the executable For example the samples for the default event on a Pentium III processor for bin bash becomes root bin bash dep root bin bash CPU_CLK_UNHALTED 100000 The following tools are available to profile the sample data once it has been collected opreport opannotate Use these tools along with the binaries profiled to generate reports that can be further analyzed Chapter 41 OProfile 313 A waming The executable being profiled must be used with these tools to analyze the data If it must change after the data is collected backup the executable used to create the samples as well as the sample files Samples for each executable are written to a single sample file Samples from each dynamically linked library are also written to a single sample file While OProfile is running if the executable being monitored changes and a sample file for the executab
285. ment Conventions 5 22 Ki eestas reeni Eies nE EE EREVENT EEV STEINER ii 4 Activate Your SUDSCDUON noiera oi A E RA EAR RRE EOSTA v 4 1 Provide a Red Hat Login 4 2 Provide Your Subscription Number ssssssssssssessssersrestsssrsrtstssresrsrerentsnsersntsreses v 4 3 Connect Your Syste sesira sasscesesscesdevacssececsasesisauetezg saves saaseesaidavadeoasialssiasescvevse vi 5 Using the Mouse vi 6 Copying and Pasting Text With X 7 More to Come esceeceeees 7 1 Send in Your Feedbac I Installation Related Information 1 Kickstart Installations 4 1 1 What are Kickstart Installations 1 2 How Do You Perform a Kickstart Installation 1 3 Creating the Kickstart File L4 Kickstart Opon Senensi iiet eE dina EN TR 1 5 Package Selections in e E EE EEEE 1 6 Pre installation Script 1 7 Post installation Script 1 8 Making the Kickstart File Available eeseeeeeeeeseeeseseesesersesesrersrsseesesssreeseses 22 1 9 Making the Installation Tree Available 1 10 Starting a Kickstart Installation 2 Kickstart Configurator 2 1 Basic Configuration 2 2 Installation Method Ss 2 3 Boot Loader Opon Sarosar sinirik iii iii e E E A AE ERAS 2 4 Partition Information vevcevisccecsvssrzcenseecacteceeseseaieccns ana EEE E E EEE 2 5 Network Configuration w O Ath enti Cat O10 ganii srir anaE r ESENS RE AD sip vesgssosssboesceusstssesseusdl 2 7 Firewall Con
286. mmand 1s 1 boot to make sure the initrd lt version gt img file was created the version should match the version of the kernel just installed On iSeries systems the initial RAM disk file and vmlinux file are combined into one file which is created with the addRamDisk command This step is performed automatically if the kernel and its associated packages are installed or upgraded from the RPM packages distributed by Red Hat Inc thus it does not need to be executed manually To verify that it was created use the command 1s 1 boot to make sure the boot vmlinitrd lt kernel version gt file was created the version should match the version of the kernel just installed The next step is to verify that the boot loader has been configured to boot the new kernel Refer to Section 37 6 Verifying the Boot Loader for details 37 6 Verifying the Boot Loader The kernel RPM package configures the boot loader to boot the newly installed kernel except for IBM eServer iSeries systems However it does not configure the boot loader to boot the new kernel by default It is always a good idea to confirm that the boot loader has been configured correctly This is a crucial step If the boot loader is configured incorrectly the system does not boot into Red Hat Enterprise Linux properly If this happens boot the system with the boot media created earlier and try configuring the boot loader again 37 6 1 x86 Systems All x86 systems use GRUB as
287. mount daemon s to reload by typing the following command at a shell prompt sbin service autofs reload To learn how to configure autofs to start at boot time and for information on managing services refer to Chapter 20 Controlling Access to Services Chapter 22 Network File System NFS 171 22 2 3 Using TCP The default transport protocol for NFSv4 is TCP however the Red Hat Enterprise Linux 4 kernel includes support for NFS over UDP To use NFS over UDP include the o udp option to mount when mounting the NFS exported file system on the client system There are three ways to configure an NFS file system export On demand via the command line client side automatically via the etc fstab file client side and automatically via autofs configuration files such as etc auto master and etc auto misc server side with NIS For example on demand via the command line client side mount o udp shadowman example com misc export misc local When the NFS mount is specified in etc fstab client side server usr local pub pub nfs rsize 8192 wsize 8192 timeo 14 intr udp When the NFS mount is specified in an autofs configuration file for a NIS server available for NIS enabled workstations myproject rw soft intr rsize 8192 wsize 8192 udp penguin example net proj52 Since the default is TCP if the o udp option is not specified the NFS exported file system is ac cessed via TCP The advantages of using TCP include the foll
288. ms File system refers to the files and directories stored on a computer A file system can have different formats called file system types These formats determine how the information is stored as files and directories Some file system types store redundant copies of the data while some file system types make hard drive access faster This part discusses the ext3 file system types Table of Contents 6 The ext3 File System sssssssssssssssssesssessssssssseeessessessesesesssssesessecssesssesessssesseessesessseseesesssessesevee 59 7 Logical Volume Manager LVM ssssssssssssssssssessssssesssesssssesesessesssesssessssssesseessesesssesessesssesses 63 8 LVM Configurations he sessionerne oossoo noissa o i e res e etenee 65 9 Redundant Array of Independent Disks RAID E R 10 Software RAID Configuration s seessesesseeresessoseoresreseocososroroososeerescososeesesseseoroseoreseoseorereseesoseesee 77 LL Swap Space investo cerises cire i oi or o AS See e A EE eS 85 12 Managing Disk Storage sssssssssscssssssesssesesesessesssesesessssssesssesssseessssessasesssessssasssesssessasesssesesee 89 13 Implementing Disk Quotas sssssscssssseecescecessscssescsesessesessesessssesssseesessesessssessssessesseseaseseseess 97 14 Access Control Lists Chapter 6 The ext3 File System The default file system is the journaling ext3 file system 6 1 Features of ext3 The ext3 file system is essentially an e
289. mum allowable size Z Force to be a primary partition canca 2x Figure 8 3 Creation of the Boot Partition Click OK to return to the main screen The following figure displays the boot partition correctly set Disk Setup Drive jdev sda 8676 MB Model IBM PSG ST39103LC Free 8573 MB Choose where you would like Red Hat Enterprise Linux AS to Drive dew sdb 8676 MB Model IBM PSG ST39204LC 1 Free be installed 3678 MB If you do not know how to partition your system or if you j Head help wih using ha New Edit Delete Reset RAD iwm manual partitioning tools refer e to the product documentation ae RAIDVVolume TYP Format Mp Start End i 7 Hard Drives If you used automatic 5 V dev sda partitioning you can either accept the current partition Idev sdal boot ext3 v 12 1 B settings click Next or modify Free Free space 8574 14 1106 the setup using the manual Y dev sdb partitioning tool Free Free space 8679 11107 Ifyou are manually partitioning your system you can see your current hard drive s and partitions displayed below Use Hide RAID device LVM Volume Group members hide Help ToRelease Noes a Back gt Net Figure 8 4 The boot Partition Displayed 8 2 2 Creating the LVM Physical Volumes Once the boot partition is created the remainder of all disk space c
290. n For instructions on how to configure the network interface card with PXE support to boot from the network consult the documentation for the NIC It varies slightly per card After the system boots the installation program refer to the Red Hat Enterprise Linux Installation Guide 48 Chapter 3 PXE Network Installations Chapter 4 Diskless Environments Some networks require multiple systems with the same configuration They also require that these systems be easy to reboot upgrade and manage One solution is to use a diskless environment in which most of the operating system which can be read only is shared from a central server between the clients The individual clients have their own directories on the central server for the rest of the operating system which must be read write Each time the client boots it mounts most of the OS from the NFS server as read only and another directory as read write Each client has its own read write directory so that one client can not affect the others The following steps are necessary to configure Red Hat Enterprise Linux to run on a diskless client 1 Install Red Hat Enterprise Linux on a system so that the files can be copied to the NFS server Refer to the Red Hat Enterprise Linux Installation Guide for details Any software to be used on the clients must be installed on this system and the busybox anaconda package must be installed 2 Create a directory on the NFS server to contain
291. n increasingly being used in small to large networks NTDOM or ADS server It is used in small to large networks C Enable LDAP Support nfigure LDAP C Enable Winbind Support O Cache User Information R Cancel 2 OK Figure 27 1 User Information The following list explains what each option configures Enable NIS Support Select this option to configure the system as an NIS client which connects to an NIS server for user and password authentication Click the Configure NIS button to specify the NIS domain and NIS server If the NIS server is not specified the daemon attempts to find it via broadcast The ypbind package must be installed for this option to work If NIS support is enabled the portmap and ypbind services are started and are also enabled to start at boot time Enable LDAP Support Select this option to configure the system to retrieve user information via LDAP Click the Configure LDAP button to specify the LDAP Search Base DN and LDAP Server If Use TLS to encrypt connections is selected Transport Layer Security is used to encrypt passwords sent to the LDAP server The openldap clients package must be installed for this option to work For more information about LDAP refer to the Red Hat Enterprise Linux Reference Guide Enable Hesiod Support Select this option to configure the system to retrieve information from a remote Hesiod database including user information
292. n 500 f Exit with an error if the group already exists The group is not altered If g and f are specified but the group already exists the g option is ignored Table 33 2 groupadd Command Line Options 33 5 3 Password Aging For security reasons it is good practice to require users to change their passwords periodically This can be done when adding or editing a user on the Password Info tab of the User Manager To configure password expiration for a user from a shell prompt use the chage command followed by an option from Table 33 3 followed by the username of the user 252 Chapter 33 User and Group Configuration EB nportant Shadow passwords must be enabled to use the chage command Option Description o m days Specify the minimum number of days between which the user must change passwords If the value is 0 the password does not expire M days Specify the maximum number of days for which the password is valid When the number of days specified by this option plus the number of days specified with the a option is less than the current day the user must change passwords before using the account d days Specify the number of days since January 1 1970 the password was changed I days Specify the number of inactive days after the password expiration before locking the account If the value is 0 the account is not locked after the password expires E date Specify the date on which the account is locke
293. n also be used with an asterisk For instance the value 3 can be used in the month field to run the task every third month Any lines that begin with a hash mark are comments and are not processed As shown in the etc crontab file the run parts script executes 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 directories should be shell scripts If a cron task is required 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 35 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 35 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 Whe
294. n the changes to the crontab are saved the crontab is stored according to username and written to the file var spool cron username The cron daemon checks the etc crontab file the etc cron d directory and the var spool cron directory every minute for any changes If any changes are found they are loaded into memory Thus the daemon does not need to be restarted if a crontab file is changed 35 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 Chapter 35 Automated Tasks 277 The root user can always use cron regardless of the usernames listed in the access control files If the file cron allow exists only users listed in it are allowed to use cron and the cron deny file is ignored If cron allow does not exist users listed in cron deny are not allowed to use cron 35 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 20 Controlling Access to Services for details on starting the
295. n the window shown in Figure 34 3 enter a unique name for the printer in the Name text field The printer name cannot contain spaces and must begin with a letter The printer name may contain letters numbers dashes and underscores _ Optionally enter a short description for the printer which can contain spaces Select Networked JetDirect from the Select a queue type menu and click Forward Queue type Select a queue type Networked JetDirect Printer Port printer example com 9100 S Help Cancel lt q Back gt Forward Figure 34 9 Adding a JetDirect Printer Text fields for the following options appear Printer The hostname or IP address of the JetDirect printer Port The port on the JetDirect printer that is listening for print jobs The default port is 9100 Next select the printer type Refer to Section 34 7 Selecting the Printer Model and Finishing for de tails 34 7 Selecting the Printer Model and Finishing After selecting the queue type of the printer the next step is to select the printer model A window similar to Figure 34 10 appears If it was not auto detected select the model from the list The printers are divided by manufacturers Select the name of the printer manufacturer from the pulldown menu The printer models are updated each time a different manufacturer is selected Select the printer model from the list Chapter 34 Printer C
296. nableldapauth use this option to specify 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 use this option to specify the DN 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 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 direc tories UIDs or shells If you enable Kerberos you must 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 Chapter 1 Kickstart Installations 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 enablehesiod Enable Hesiod support for looking up
297. nation of the Secure Sockets Layer SSL protocol and in most cases a digital certificate from a Certificate Authority CA SSL handles the encrypted communications as well as the mutual authentication between browsers and your secure server The CA approved digital certificate provides authentication for your secure server the CA puts its repu tation behind its certification of your organization s identity When your browser is communicating using SSL encryption the https prefix is used at the beginning of the Uniform Resource Locator URL in the navigation bar Encryption depends upon the use of keys think of them as secret encoder decoder rings in data for mat In conventional or symmetric cryptography both ends of the transaction have the same key which they use to decode each other s transmissions In public or asymmetric cryptography two keys co exist a public key and a private key A person or an organization keeps their private key a secret and publishes their public key Data encoded with the public key can only be decoded with the private key data encoded with the private key can only be decoded with the public key To set up your secure server use public cryptography to create a public and private key pair In most cases you send your certificate request including your public key proof of your company s identity and payment to a CA The CA verifies the certificate request and your identity and then sends back a c
298. nces between RAID 0 1 and 5 An overview of the steps required to configure RAID include Applying software RAID partitions to the physical hard drives If you wish to have the boot partition boot reside on a RAID parition it must be on a RAID 1 partition Creating RAID devices from the software RAID partitions Optional Configuring LVM from the RAID devices Refer to Chapter 8 LVM Configuration for more information on configuring LVM after first configuring RAID Creating file systems from the RAID devices Note Although the following steps are illustrated during a GUI installation the same can be done during a text based installation Configuration of software RAID must be done manually in Disk Druid during the installation process Two 9 1 GB SCSI drives dev sda and dev sdb are used in the following examples They detail how to create a simple RAID 1 configuration by implementing multiple RAID devices On the Disk Partitioning Setup screen select Manually partition with Disk Druid 10 1 Creating the RAID Partitions In a typical situation the disk drives are new or are formatted Both drives are shown as raw devices with no partition configuration in Figure 10 1 78 Chapter 10 Software RAID Configuration Disk Setup Drive dev sda 8676 MB Model IBM PSG ST39103LC 1 Free s678 me Choose where you would like Red Hat Enterprise Linux AS to Drive jdev sdb 8676 MB Model IBM PSG ST39
299. nclude 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 fa 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 are used Chapter 1 Kickstart Installations 21 Note The pre installation script section of kickstart cannot manage multiple install trees or source media This information must be included for each created ks cfg file as the pre installation script occurs during the second stage of the installation process 1 7 Post installation Script You have the option of adding commands to run on the system once the installation is complete This section must be at the end of the kickstart file and must start with the post command This section is useful for functions such as installing additional software and configuring an additional nameserver Note If you configured the network wi
300. nel 1024x768 Configure aot y ai P Video Card 53 Savage4 Configure 2 Cancel 2 OK Figure 32 2 Display Hardware Settings To change the monitor type or any of its settings click the corresponding Configure button To change the video card type or any of its settings click the Configure button beside its settings 32 3 Dual Head Display Settings If multiple video cards are installed on the system dual head monitor support is available and is configured via the Dual head tab as shown in Figure 32 3 Chapter 32 X Window System Configuration lt Use dual head Settings Hardware Dual head Second Monitor Type LCD Panel 1024x768 Configure a Second Video Card 53 Savage4 bs Resolution 1024x768 Color Depth Millions of Colors x Desktop layout Spanning Desktops Cancel 2 OK Figure 32 3 Dual Head Display Settings To enable use of dual head check the Use dual head checkbox To configure the second monitor type or any of its settings click the corresponding Configure button 245 For the Desktop layout option selecting Spanning Desktops allows both monitors to use an enlarged usable workspace Selecting Individual Desktops creates a mirrored workspace effect similar to laptops 246 Chapter 32 X Window System Configuration Chapter 33 User and Group Configuration The User Mana
301. nf 187 dhcpd leases 191 dhcrelay 192 diskless environment 47 50 global parameters 188 group 189 options 188 PXE installations 47 50 reasons for using 187 Relay Agent 192 server configuration 187 shared network 188 starting the server 191 stopping the server 191 subnet 188 dhcpd conf 187 dhcpd leases 191 dhcrelay 192 disk quotas 97 additional resources 102 assigning per file system 100 assigning per group 100 assigning per user 99 disabling 100 enabling 97 100 etc fstab modifying 97 creating quota files 98 quotacheck running 98 grace period 99 hard limit 99 management of 100 quotacheck command using to check 101 reporting 101 soft limit 99 disk storage see disk quotas parted see parted diskless environment 49 adding hosts 51 DHCP configuration 47 50 Network Booting Tool 50 NFS configuration 50 overview 49 display settings for X 243 documentation finding installed 119 drag and drop vi DSA keys generating 166 DSOs loading 212 du 304 Dynamic Host Configuration Protocol see DHCP E e2fsck 61 e2label 92 emergency mode 56 Ethernet connection see network configuration exim 297 expiration of password forcing 251 exporting NFS file Systems 171 exports 173 ext2 reverting from ext3 61 ext3 converting from ext2 60 creating 59 features 59 F feedback vii file systems 304 ext2 see ext2 ext3 see ext3 LVM see LVM NF
302. nhanced 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 e2 sck program This is a time consuming process that can delay system boot time significantly espe cially with large volumes containing a large number of files During this time any data on the volumes is unreachable The journaling provided by the ext3 file system means that this sort of file system check is no longer necessary after an unclean system shutdown The only time a consistency check occurs using ext3 is in certain rare hardware failure cases such as hard drive failures The time to recover an ext3 file system after an unclean system shutdown does not depend on the size of the file system or the number of files rather it depends on the size of the journal used to maintain consistency The default journal size takes about a second to recover depending on the speed of the hardware Data Integrity The ext3 file system provides stronger data integrity in the event that an unclean system shutdown occurs The ext3 file system allows you to choose the type and level of protection that your data receives By default the ext3 volumes are configured to keep a high level of data consistency with regard to the state of the file system Speed Despite writ
303. nitialize the disk label if installing to a brand new hard drive linux Erases all Linux partitions none default Do not remove any partitions cmdline optional Perform the installation in a completely non interactive command line mode Any prompts for interaction halts the install This mode is useful on S 390 systems with the x3270 console device optional On most PCI systems the installation program autoprobes for Ethernet and SCSI cards properly On older systems and some PCI systems however kickstart needs a hint to find the proper devices The device command which tells the installation program to install extra modules is in this format device lt type gt lt moduleName gt opts lt options gt lt type gt Replace with either scsi or eth lt moduleName gt Replace with the name of the kernel module which should be installed opts Options to pass to the kernel module Note that multiple options may be passed if they are put in quotes For example opts aic152x 0x340 io 11 driverdisk optional Driver diskettes can be used during kickstart installations You must copy the driver diskettes s contents to the root directory of a partition on the system s hard drive Then you must use the driverdisk command to tell the installation program where to look for the driver disk driverdisk lt partition gt type lt fstype gt Alternatively a network location can be specified for t
304. niusnm geniusnmps 2 geniusprops 2 geniusscrollps 2 geniusscrollps 2 thinking thinkingps 2 logitech logitechcc logibm logimman logimmanps 2 logimman logimman ps 2 logimmusb microsoft msnew msintelli msintellips 2 msintelliusb msbm mousesystems mmseries mmhittab sun none This list can also be found in the usr 1lib python2 2 site packages rhpl mouse py file which is part of the rhp1 package If the mouse command is given without any arguments or it is omitted the installation program attempts to automatically detect the mouse This procedure works for most modern mice network optional Configures network information for the system If the kickstart installation does not require net working in other words it is not installed over NFS HTTP or FTP networking is not config ured for the system If the installation does require networking and network information is not provided in the kickstart file the installation program assumes that the installation should be done over eth0 via a dynamic IP address BOOTP DHCP and configures the final installed system to determine its IP address dynamically The network option configures networking information for kickstart installations via a network as well as for the installed system Chapter 1 Kickstart Installations 11 bootproto One of dhcp bootp or static It defaults to dhcp bootp and dhcp are treated the same The DHCP method uses a DHCP server syste
305. nless the kickstart file is a local file such as ks floppy since the installation program configures 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 12 Chapter 1 Kickstart Installations hostname Hostname for the installed system part or partition required for installs ignored for upgrades Creates a partition on the system If more than one Red Hat Enterprise Linux installation exists on the system on different parti tions the installation program prompts the user and asks which installation to upgrade A warming All partitions created are formatted as part of the installation process unless noformat and onpart are used For a detailed example of part in action refer to Section 1 4 1 Advanced Partitioning Example lt mntpoint gt The lt mntpoint gt is where the partition is mounted and must be of one of the following forms lt path gt For example usr home swap The partition is used as swap space To determine the size of the swap partition automatically use the recommended op tion swap recommended The minimum size of the automatically generated swap partition is
306. nning When the system is rebooted it continues to boot the runlevel as specified in etc inittab 20 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 1ibwrap 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 hosts allow contains a list of rules that allow clients to access the network services controlled by xinetd and hosts deny contains rules to deny access The hosts allow file takes precedence over the hosts deny file Permissions to grant or deny access can be based on individual IP address or hostnames or on a pattern of clients Refer to the Red Hat Enterprise Linux Reference Guide and hosts_access in section 5 of the man pages man 5 hosts_access for details 20 2 1 xinetd To control access to Internet services use xinetd which is a secure replacement for inetd The xinetd daemon conserves system resources provides access control and logging and can be used to start special purpose servers xinetd can be used to provide access only to particular hosts to deny access to particular hosts to provide access to a service at certain times to limit the rate of incoming connections and or the load created by connections and more xinetd runs constantly and
307. nstalled in your usr bin directory with the samba package 2 Change the permissions of the Samba password file so that only root has read and write permis sions chmod 600 etc samba smbpasswd 3 The script does not copy user passwords to the new file and a Samba user account is not active until a password is set for it For higher security it is recommended that the user s Samba password be different from the user s system password To set each Samba user s password use the following command replace username with each user s username smbpasswd username 4 Encrypted passwords must be enabled Since they are enabled by default they do not have to be specifically enabled in the configuration file However they can not be disabled in the configuration file either In the file etc samba smb conf verify that the following line does not exist encrypt passwords no If it does exist but is commented out with a semi colon at the beginning of the line then the line is ignored and encrypted passwords are enabled If this line exists but is not commented out either remove it or comment it out To specifically enable encrypted passwords in the configuration file add the following lines to etc samba smb conf encrypt passwords yes smb passwd file etc samba 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 automatical
308. nually Figure 18 18 shows an example of one alias for the etno 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 146 Chapter 18 Network Configuration File Profile Help SHO x New Edit Copy Delete Activate Deactivate Devices Hardware DNS Hosts ga You may configure network devices associated with physical hardware here Multiple logical devices can be associated with a single piece of hardware Device Nickname Type Ethernet amp Active etho etho Ethernet Active Profile Common Figure 18 18 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 addresses etho eth0 1 lo 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 dr
309. o DirectoryIndex such as index html exists in the requested directory Multiview Support content negotiated multiviews this option is disabled by default SymLinksIfOwnerMatch Only follow symbolic links if the target file or directory has the same owner as the link To specify options for specific directories click the Add button beside the Directory list box A window as shown in Figure 25 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 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 ExecCGI Process Allow list before Deny list FollowSymLinks Includes Deny List IncludesNOEXEC Indexes Deny access from all hosts C Muttiviews O Deny hosts from SymLinks lfOwnerMatch Allow List Allow
310. o configure your system you should learn how to gather essential system information For example you should know how to find the amount of free memory the amount of available hard drive space how your hard drive is partitioned and what processes are running This chapter discusses how to retrieve this type of information from your Red Hat Enterprise Linux system using simple commands and a few simple programs 40 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 was running when you invoked the command If you want a constantly updated list of running processes use top as described below The ps output can be long To prevent it from scrolling off the screen you can pipe it through less ps aux less You can use the ps command in combination with the grep command to see if a process is running For example to determine if Emacs is running use the following command ps ax grep emacs The top command displays currently running processes and important information about them in cluding their memory and CPU usage The list is both real time and interactive An example of top s output is provided as follows top 14 01 42 up 9 days 23 48 4 users load average 0 10 0 13 0 07 Tasks 96 total 2 running
311. o read and write to the directory home share on the Samba server from a Samba client 23 2 3 Encrypted Passwords Encrypted passwords are enabled by default because it is more secure If encrypted passwords are not used plain text passwords are used which can be intercepted by someone using a network packet sniffer It is recommended that encrypted passwords be used The Microsoft SMB Protocol originally used plain text passwords However Windows NT 4 0 with Service Pack 3 or higher Windows 98 Windows 2000 Windows ME and Windows XP require encrypted Samba passwords To use Samba between a Linux system and a system running one of these Windows operating systems you can either edit your Windows registry to use plaintext passwords or configure Samba on your Linux system to use encrypted passwords If you choose to modify your 182 Chapter 23 Samba registry you must do so for all of your Windows machines this is risky and may cause further conflicts It is recommended that you use encrypted passwords for better security To configure Samba to use encrypted passwords follow these steps 1 Create a separate password file for Samba To create one based on your existing etc passwd file at a shell prompt type the following command cat etc passwd mksmbpasswd sh gt etc samba smbpasswd If the system uses NIS type the following command ypcat passwd mksmbpasswd sh gt etc samba smbpasswd The mksmbpasswd sh script is i
312. o stop the connection execute the following command as root on each host for host to host IPsec or each IPsec router for network to network IPsec replace lt ipsec nick gt with the one word nickname configured earlier such as ipsec0 sbin ifdown lt ipsec nick gt 18 13 Saving and Restoring the Network Configuration The command line version of Network Administration Tool can be used to save the system s network configuration to a file This file can then be used to restore the network settings to a Red Hat Enterprise Linux system This feature can be used as part of an automated backup script to save the configuration before upgrading or reinstalling or to copy the configuration to a different Red Hat Enterprise Linux system To save or export the system s network configuration to the file tmp network config execute the following command as root system config network cmd e gt tmp network config To restore or import the network configuration from the file created from the previous command execute the following command as root system config network cmd i c f tmp network config The i option means to import the data the c option means to clear the existing configuration prior of importing and the option specifies that the file to import is as follows 152 Chapter 18 Network Configuration Chapter 19 Basic Firewall Configuration Just as a firewall in a building attempts to prevent a fire from spr
313. o work Refer to the Red Hat Enterprise Linux Reference Guide for more information about LDAP Use Shadow Passwords Select this option to store passwords in shadow password format in the etc shadow file instead of etc passwd Shadow passwords are enabled by default during installation and are highly recommended to increase the security of the system The shadow utils package must be installed for this option to work For more information about shadow passwords refer to the Users and Groups chapter in the Red Hat Enterprise Linux Reference Guide Enable SMB Support This option configures PAM to use an SMB server to authenticate users Click the Configure SMB button to specify Workgroup Specify the SMB workgroup to use Domain Controllers Specify the SMB domain controllers to use Winbind Select this option to configure the system to connect to a Windows Active Directory or a Windows domain controller User information can be accessed as well as server authentication options can be configured 226 Chapter 27 Authentication Configuration Use MD5 Passwords Select this option to enable MD5 passwords which allows passwords to be up to 256 characters instead of eight characters or less It is selected by default during installation and is highly recommended for increased security 27 3 Command Line Version The Authentication Configuration Tool can also be run as a command line tool with no interface
314. oad the configuration file service nfs reload 4 4 Finish Configuring the Diskless Environment To use the graphical version of the Network Booting Tool you must be running the X Window System have root privileges and have the system config netboot RPM package installed To start the Network Booting Tool from the desktop go to Applications the main menu on the panel gt System Settings gt Server Settings gt Network Booting Service Or type the command system config netboot at a shell prompt for example in an XTerm or a GNOME terminal If starting the Network Booting Tool for the first time select Diskless from the First Time Druid Otherwise select Configure gt Diskless from the pull down menu and then click Add A wizard appears to step you through the process 1 Click Forward on the first page 2 On the Diskless Identifier page enter a Name and Description for the diskless environment Click Forward 3 Enter the IP address or domain name of the NFS server configured in Section 4 3 Configuring the NFS Server as well as the directory exported as the diskless environment Click Forward Chapter 4 Diskless Environments 51 4 The kernel versions installed in the diskless environment are listed Select the kernel version to boot on the diskless system 5 Click Apply to finish the configuration After clicking Apply the diskless kernel and image file are created based on the kernel selected They are copi
315. ob has been completed Display the time that the job is executed Table 35 1 at and batch Command Line Options 35 2 5 Controlling Access to At and Batch The etc at allow and etc at deny files can be used to restrict access to the at and batch Chapter 35 Automated Tasks 279 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 access control files If the file at allow exists only users listed in it are allowed to use at or batch and the at deny file is ignored If at allow does not exist users listed in at deny are not allowed to use at or batch 35 2 6 Starting and Stopping the Service To start the at service use the command sbin service atd start To stop the service use the command sbin service atd stop It is recommended that you start the service at boot time Re fer to Chapter 20 Controlling Access to Services for details on starting the cron service automatically at boot time 35 3 Additional Resources To learn more about configuring automated tasks refer to the following resources 35 3 1 Installed Documentation cron man page overview of cron crontab man page
316. ocatable Version 1 10 Vendor Red Hat Inc Release e051 Build Date Mon 20 Sep 2004 05 58 10 PM EDT Install Date not installed Build Host tweety build redhat com Group System Environment Base Source RPM crontabs 1 10 7 src rpm Size 1004 License Public Domain Signature DSA SHA1 Wed 05 Jan 2005 06 05 25 PM EST Key ID 219180cddb42a60e Packager Red Hat Inc lt http bugzilla redhat com bugzilla gt Summary Root crontab files used to schedule the execution of programs Description The crontabs package contains root crontab files Crontab is the program used to install uninstall or list the tables used to drive the cron daemon The cron daemon checks the crontab files to see when particular commands are scheduled to be executed If commands are scheduled then it executes them Perhaps you now want to see what files the crontabs RPM installs You would enter the following rpm qlp crontabs 1 10 5 noarch rpm 120 Chapter 15 Package Management with RPM The output is similar to the following etc cron daily etc cron hourly etc cron monthly etc cron weekly etc crontab usr bin run parts These are just a few examples As you use it you will find many more uses for RPM 15 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 15 5 1 Installed D
317. ocumentation e rpm help This command displays a quick reference of RPM parameters man rpm The RPM man page gives more detail about RPM parameters than the rpm help command 15 5 2 Useful Websites http www rpm org The RPM website http www redhat com mailman listinfo rpm list The RPM mailing list is archived here To subscribe send mail to lt rpm list request redhat com gt with the word subscribe in the subject line 15 5 3 Related Books Red Hat RPM Guide by Eric Foster Johnson Wiley John amp Sons Incorporated This book is a comprehensive guide to RPM from installing package to building RPMs Chapter 16 Package Management Tool During installation a default set of software packages are installed Because people use their com puters differently users might want to install or remove packages after installation The Package Management Tool allows users to perform these actions The X Window System is required to run the Package Management Tool To start the application go to Applications the main menu on the panel gt System Settings gt Add Remove Applications or type the command system config packages at shell prompt The same interface automatically appears when you insert the Red Hat Enterprise Linux CD 1 into your computer Add or Remove Packages X Window System 35 36 Details FA Install this group of packages to use the base graphical X amp
318. of processes displayed You are prompted to enter the number Sort by memory usage Sort by CPU usage Table 40 1 Interactive top commands If you prefer a graphical interface for top you can use the GNOME System Monitor To start it from the desktop select Applications the main menu on the panel gt System Tools gt System Monitor or type gnome system monitor at a shell prompt such as an XTerm Select the Process Listing tab The GNOME System Monitor allows you to search for a process in the list of running process as well as to 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 is 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 Chapter 40 Gathering System Information 303 Eile Edit View Help Process Listing Resource Monitor Search View My Processes Process Name v User Memory X Server Memory Nice 1D al Yash andriusb 4 9MB 0 bytes O 18245 7 sh andriusb 5 3MB 0 bytes O 18279 X xinit andriusb 27MB 0 bytes O 18292 gnome session andriusb 20 3 MB 0 bytes 0 18322 bonobo activat
319. of the Setup tab Select the checkbox beside the unit mask to enable it for the event On the Configuration tab to profile the kernel enter the name and location of the vmlinux file for the kernel to monitor in the Kernel image file text field To configure OProfile not to monitor the kernel select No kernel image 318 Chapter 41 OProfile Setup Configuration Kemel image file _ boot vmlinux 2 4 21 1 1931 2 349 2 2 entsmp L No kernel image C verbose C Per application kemel samples files Per application shared libs samples files Profiler running 1 hours 44 mins 32 interrupts second total 176226 Elush profiler data Stop profiler Save and guit Figure 41 2 OProfile Configuration If the Verbose option is selected the oprofiled daemon log includes more information If Per application kernel samples files is selected OProfile generates per application profiles for the kernel and kernel modules as discussed in Section 41 2 3 Separating Kernel and User space Profiles This is equivalent to the opcontrol separate kernel command If Per application shared libs samples files is selected OProfile generates per application profiles for libraries This is equiva lent to the opcontrol separate library command To force data to be written to samples files as discussed in Section 41 5 Analyzing the Data click the Flush profiler data button This is equivalent to th
320. ofiles after the system has booted go to Main Menu on the Panel gt System Tools gt Network Device Control or type the command system control network to select a profile and activate it The activate profile section only appears in the Network Device Control interface if more than the default Common interface exists Alternatively execute the following command to enable a profile replace lt profilename gt with the name of the profile system config network cmd profile lt profilename gt activate 18 11 Device Aliases Device aliases are virtual devices associated with the same physical hardware but they can be acti vated at the same time to have different IP addresses They are commonly represented as the device name followed by a colon and a number for example eth0 1 They are useful if you want to have multiple IP address for a system but the system only has one network card After configuring the Ethernet device such as et h0 to use a static IP address DHCP does not work with aliases go to the Devices tab and click New Select the Ethernet card to configure with an alias set the static IP address for the alias and click Apply to create it Since a device already exists for the Ethernet card the one just created is the alias such as eth0 1 A waming If you are configuring an Ethernet device to have an alias neither the device nor the alias can be configured to use DHCP You must configure the IP addresses ma
321. ol additional resources 208 related books 208 securing 213 APXS 212 at 277 additional resources 279 authconfig see Authentication Configuration Tool authentication 223 Authentication Configuration Tool 223 authentication 224 Kerberos support 225 LDAP support 225 MDS passwords 225 shadow passwords 225 SMB support 225 Winbind 225 command line version 226 user information 223 cache 224 Hesiod 224 LDAP 224 NIS 224 Winbind 224 autofs 170 etc auto master 170 Automated Tasks 275 batch 277 additional resources 279 boot media 286 boot partition 67 booting emergency mode 56 rescue mode 54 single user mode 56 C CA see secure server chage command forcing password expiration with 251 chkconfig 161 color depth 243 command line options printing from 272 configuration console access 231 NFS 169 console making files accessible from 232 console access configuring 231 defining 232 disabling 232 enabling 233 conventions document ii copying and pasting text when using X vi Cron 275 additional resources 279 configuration file 275 322 example crontabs 276 user defined tasks 276 crontab 275 CtrlAltDel shutdown disabling 231 CUPS 257 D date configuration 235 dateconfig see Time and Date Properties Tool devel package 212 df 304 DHCP 187 additional resources 193 client configuration 192 command line options 191 connecting to 192 dhcpd co
322. ol can be used after modi fying the file manually provided the file was modified with correct syntax 22 3 1 Command Line Configuration If you prefer editing configuration files using a text editor or if you do not have the X Window System installed you can modify the configuration file directly The etc exports file controls what directories the NFS server exports Its format is as follows directory hostname options The only option that needs to be specified is one of sync or async sync is recommended If sync is specified the server does not reply to requests before the changes made by the request are written to the disk For example misc export speedy example com sync 174 Chapter 22 Network File System NFS would allow users from speedy example comto mount misc export with the default read only permissions but misc export speedy example com rw sync would allow users from speedy example comto mount misc export with read write privileges Refer to Section 22 3 2 Hostname Formats for an explanation of possible hostname formats Refer to the Red Hat Enterprise Linux Reference Guide for a list of options that can be specified QO caution Be careful with spaces in the etc exports file If there are no spaces between the hostname and the options in parentheses the options apply only to the hostname If there is a space between the hostname and the options the options apply to the rest of the world For exam
323. om the name of your application such as our sample foo program to the usr bin consolehelper application cd usr bin in 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 usr bin foois executed consolehelper is called which authenticates the user with the help of usr sbin userhelper To authenticate the user consolehelper asks for the user s password if etc pam d foo is a copy of etc pam d halt otherwise it does precisely what is specified in etc pam d foo and then runs usr sbin foo with root permissions In the PAM configuration file an application can be configured to use the pam_timestamp module to remember or 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_timestamp and run from the same session is automatically authenticated for the user the user does not have to enter the root password again This module is included in the pam package To
324. on go to the Main Menu Button gt System Settings gt Server Settings gt HTTP or type the command system config httpd at a shell prompt for example in an XTerm or GNOME Terminal The HTTP Configuration Tool allows you to configure the etc httpd conf httpd conf con figuration file for the Apache HTTP Server It does not use the old srm conf or access conf configuration files leave them empty Through the graphical interface you can configure directives such as virtual hosts logging attributes and maximum number of connections Only modules provided with Red Hat Enterprise Linux can be configured with the HTTP Configu ration Tool If additional modules are installed they can not be configured using this tool QO caution Do not edit the etc httpd conf httpd conf configuration file by hand if you wish to use this tool The HTTP Configuration Tool generates this file after you save your changes and exit the program If you want to add additional modules or configuration 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 follows 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 To serve more than one URL or virtual host add any additional virtual hosts Conf
325. on for basic administration concepts the Red Hat Enterprise Linux System Administration Guide for general customization instructions and the Red Hat Enterprise Linux Security Guide for security related instructions This guide contains information about topics for advanced users HTML PDF and RPM versions of the manuals are available on the Red Hat Enterprise Linux Docu mentation CD and online at http www redhat com docs gt Note Although this manual reflects the most current information possible read the Red Hat Enterprise Linux Release Notes for information that may not have been available prior to our documentation being finalized The Release Notes can be found on the Red Hat Enterprise Linux CD 1 online at http www redhat com docs or in the usr share doc redhat release 4 lt product gt directory after installation where lt product gt is AS ES WS Of Desktop 2 Architecture specific Information Unless otherwise noted information contained in this manual applies only to the x86 processor and processors featuring the Intel Extended Memory 64 Technology Intel EM64T and AMD64 tech nologies For architecture specific information refer to the Red Hat Enterprise Linux Installation Guide for your respective architecture 3 Document Conventions In this manual certain words are represented in different fonts typefaces sizes and weights This highlighting is systematic different words are represented in the same
326. on size for the new partition Optionally you can also choose from the following In the Additional Size Options section choose to make the partition a fixed size up to a chosen size or fill the remaining space on the hard drive If you selected swap as the file system type you can select to have the installation program create the swap partition with the recommended size instead of specifying a size Force the partition to be created as a primary partition 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 32 Mount Point File System Type ext3 Size MB 1 Additional Size Options Fixed size ap i O Grow to maximum of MB 1 O Fill all unused space on disk CO Use recommended swap size C Force to be a primary partition asprimary Make partition on specific drive ondisk Drive for example hda or sdc C Use existing partition onpart Partition for example hdal or sdc3 7 Format partition X Cancel Pox Figure 2 5 Creating Pa
327. on with the same version as the kernel package just installed boot dev sdal init message Welcome to Red Hat Enterprise Linux Hit lt TAB gt for boot options partition 2 timeout 30 install usr lib yaboot yaboot delay 10 nonvram image vmlinux 2 6 9 5 EL label old read only initrd initrd 2 6 9 5 EL img append root LABEL image vmlinux 2 6 9 5 EL label linux read only initrd initrd 2 6 9 5 EL img append root LABEL Notice that the default is not set to the new kernel The kernel in the first image is booted by default To change the default kernel to boot either move its image stanza so that it is the first one listed or add the directive default and set it to the label of the image stanza that contains the new kernel Begin testing the new kernel by rebooting the computer and watching the messages to ensure that the hardware is detected properly 292 Chapter 37 Manually Upgrading the Kernel Chapter 38 Kernel Modules The Linux kernel has a modular design At boot time only a minimal resident kernel is loaded into memory Thereafter whenever a user requests a feature that is not present in the resident kernel a kernel module sometimes referred to as a driver is dynamically loaded into memory During installation the hardware on the system is probed Based on this probing and the information provided by the user the installation program decides which modules need to be loaded at boot time The installa
328. onfiguration 265 Printer model Select the printer manufacturer and model Notes HP z 2000C 2500C 2500CM 2563 bi is Help Cancel lt 4 Back D Forward Figure 34 10 Selecting a Printer Model The recommended print driver is selected based on the printer model selected The print driver pro cesses the data that you want to print into a format the printer can understand Since a local printer is attached directly to your computer you need a print driver to process the data that is sent to the printer If you are configuring a remote printer IPP LPD SMB or NCP the remote print server usually has its own print driver If you select an additional print driver on your local computer the data is filtered multiple times and is converted to a format that the printer can not understand To make sure the data is not filtered more than once first try selecting Generic as the manufacturer and Raw Print Queue or Postscript Printer as the printer model After applying the changes print a test page to try out this new configuration If the test fails the remote print server might not have a print driver configured Try selecting a print driver according to the manufacturer and model of the remote printer applying the changes and printing a test page GC You can select a different print driver after adding a printer To do this start the Printe
329. onfiguration 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 20 Controlling Access to Services for information on how to manage services If you reinstall the reinstalled system creates a new set of identification keys Any clients who had connected to the system with any of the OpenSSH tools before the reinstall will see the following message CEAAEEEAAEEEEAEEEEAAEEEAEREEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE WARNING REMOTE HOST IDENTIFICATION HAS CHANGED CEAAEEEAAEEEEAEEEEAAEEEAEREEEEEEAEEEEEEAEEEEEAEEEEECEAEEEEE 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 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 164 Chapter 21 OpenSSH 21 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 21 3 1 Using the ssh Command The ssh command is a secure replacemen
330. onfiguring the ISDN device it appears in the device list as a device with type ISDN as shown in Figure 18 5 Be sure to select File gt Save to save the changes After adding the ISDN device you can edit its configuration by selecting the device from the device list and clicking Edit For example when the device is added it is configured not to start at boot time by default Edit its configuration to modify this setting Compression PPP options login name password and more can be changed When the device is added it is not activated immediately as seen by its Inactive status To activate the device select it from the device list and click the Activate button If the system is configured to activate the device when the computer starts the default this step does not have to be performed again Chapter 18 Network Configuration 135 File Profile Help B B x New Edit Copy Delete Activate Deactivate Devices Hardware IPsec DNS Hosts ji You may configure network devices associated with 3 a physical hardware here Multiple logical devices can be 5 associated with a single piece of hardware Profile Status Device Nickname Type v active pppO Provide D Figure 18 5 ISDN Device 18 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 a
331. ool can be used to configure a system as an NFS server 172 Chapter 22 Network File System NFS To use the NFS Server Configuration Tool you must be running the X Window System have root privileges and have the system config nfs RPM package installed To start the application select the Main Menu Button on the Panel gt System Settings gt Server Settings gt NFS or type the command system config nfs Eile Help f B Add Properties Delete Help Directory Hosts Permissions Figure 22 1 NFS Server Configuration Tool To add an NFS share click the Add button The dialog box shown in Figure 22 2 appears The Basic tab requires the following information e Directory Specify the directory to share such as tmp e Host s Specify the host s with which to share the directory Refer to Section 22 3 2 Hostname Formats for an explanation of possible formats Basic permissions Specify whether the directory should have read only or read write permis sions Basic General Options User Access Directory tmp Browse Host s example com Basic permissions Read only Read Write 3 Cancel OK Figure 22 2 Add Share The General Options tab allows the following options to be configured e Allow connections from port 1024 and higher Services started on port numbers less than 1024 must be started as root
332. ooter at the bottom of error pages 25 2 2 Logging Use the Logging tab to configure options for specific transfer and error logs By default the server writes the transfer log to the var log httpd access_log file and the error log to the var log httpd error_log file The transfer log contains a list of all attempts to access the Web server It records the IP address of the client that is attempting to connect the date and time of the attempt and the file on the Web server that it is trying to retrieve Enter the name of the path and file in which to store this information If the path and file name do not start with a slash the path is relative to the server root directory as configured This option corresponds to the TransferLog directive Chapter 25 Apache HTTP Server Configuration 199 Page Options Logging Environment Performance Transfer Log Log to File logs access_log O Log to Program O Use System Log Use custom logging facilities Custom Log String Error Log Log to File logs error_log Log to Program O Use System Log Log Level Error hs Reverse DNS Lookup Reverse Lookup x T Help 3 Cancel 2 OK Figure 25 4 Logging You can configure a custom log format by checking Use custom logging facilities and entering a custom log string in the Custom Log String field This configures the LogFormat di
333. opped 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 18 12 Establishing an IPsec Connection IPsec stands for Internet Protocol Security It is a Virtual Private Network VPN solution in which an encrypted connection is established between two systems host to host or two networks network to network Chapter 18 Network Configuration 147 Om Go to http www ipsec howto org for more information about IPsec 18 12 1 Host to Host Connection A host to host IPsec connection is an encrypted connection between two systems both running IPsec with the same authentication key With the IPsec connection active any network traffic between the two hosts is encrypted To configure a host to host IPsec connection use the following steps for each host n oo 9 10 11 12 1 Start the Network Administration Tool 2 From the IPsec tab select New
334. or HTTP as the network installation type depending on which one was configured previously If FTP is selected and anonymous FTP is not being used uncheck Anonymous FTP and provide a valid username and password combination Kickstart Specify the location of the kickstart file The file can be a URL or a file stored locally diskette The kickstart file can be created with the Kickstart Configurator Refer to Chapter 2 Kickstart Configurator for details e Server Provide the IP address or domain name of the NFS FTP or HTTP server Location Provide the directory shared by the network server If FTP or HTTP was selected the directory must be relative to the default directory for the FTP server or the document root for the HTTP server For all network installations the directory provided must contain the RedHat directory of the installation tree After clicking OK the initrd img and vmlinuz files necessary to boot the installation program are transfered from images pxeboot in the provided installation tree to tftpboot linux install lt os identifier gt on the tftp server the one you are running the Network Booting Tool on 3 2 1 Command Line Configuration If the network server is not running X the pxeos command line utility which is part of the system config netboot package can be used to configure the tftp server files as described in Section 3 4 Starting the tftp Server pxeos a i lt description gt p lt
335. or file name the client system tries to mount kickstart from the BOOTP DHCP server and tries to find the kickstart file using the same lt ip addr gt kickstart file name as described above 1 9 Making the Installation Tree Available The kickstart installation must access an installation tree An installation tree is a copy of the binary Red Hat Enterprise Linux CD ROMs with the same directory structure If you are performing a CD based installation insert the Red Hat Enterprise Linux CD ROM 1 into the computer before starting the kickstart installation 24 Chapter 1 Kickstart Installations If you are performing a hard drive installation make sure the ISO images of the binary Red Hat Enterprise Linux CD ROMs are on a hard drive in the computer If you are performing a network based NFS FTP or HTTP installation you must make the installa tion tree available over the network Refer to the Preparing for a Network Installation section of the Red Hat Enterprise Linux Installation Guide for details 1 10 Starting a Kickstart Installation To begin a kickstart installation you must boot the system from boot media you have made or the Red Hat Enterprise Linux CD ROM 1 and enter a special boot command at the boot prompt The installation program looks for a kickstart file if the ks command line argument is passed to the kernel CD ROM 1 and Diskette The linux ks floppy command also works if the ks cfg file is located on a vfat o
336. org The mod_ss1 website is the definitive source for information about mod_ssl The website includes a wealth of documentation including a User Manual at http www modssl org docs Chapter 26 Apache HTTP Secure Server Configuration 221 26 11 2 Related Books Apache The Definitive Guide 2nd edition by Ben Laurie and Peter Laurie O Reilly amp Associates Inc 222 Chapter 26 Apache HTTP Secure Server Configuration Chapter 27 Authentication Configuration When a user logs in to a Red Hat Enterprise Linux system the username and password combination must be verified or authenticated as a valid and active user Sometimes the information to verify the user is located on the local system and other times the system defers the authentication to a user database on a remote system The Authentication Configuration Tool provides a graphical interface for configuring NIS LDAP and Hesiod to retrieve user information as well as for configuring LDAP Kerberos and SMB as authentication protocols Note If you configured a medium or high security level during installation or with the Security Level Con figuration Tool network authentication methods including NIS and LDAP are not allowed through the firewall This chapter does not explain each of the different authentication types in detail Instead it explains how to use the Authentication Configuration Tool to configure them For more information about the specific aut
337. orked JetDirect a printer connected directly to the network through HP JetDirect instead of to a computer Boran If you add a new print queue or modify an existing one you must apply the changes for them to take effect Clicking the Apply button saves any changes that you have made and restarts the printer daemon The changes are not written to the configuration file until the printer daemon is restarted Alternatively you can choose Action gt Apply 34 1 Adding a Local Printer To add a local printer such as one attached through a parallel port or USB port on your computer click the New button in the main Printer Configuration Tool window to display the window in Figure 34 2 Click Forward to proceed Add a new print queue On the following screens you will be asked to provide basic information for adding a new print queue You will be able to edit the more advanced options afterwards Nothing will be done to your settings until you hit Finish on the last screen T Help Cancel Back gt Forward Figure 34 2 Adding a Printer In the window shown in Figure 34 3 enter a unique name for the printer in the Name text field The printer name cannot contain spaces and must begin with a letter The printer name may contain letters numbers dashes and underscores _ Optionally enter a short description for the printer which can contain spaces Chapter 34 Prin
338. orts ACLs and the NFS client can read ACLs ACLs are utilized by the client system To disable ACLs on NFS shares when configuring the server include the no_acl option in the etc exports file To disable ACLs on an NFS share when mounting it on a client mount it with the no_ac1 option via the command line or the etc fstab file 14 2 Setting Access ACLs There are two types of ACLs access ACLs and default ACLs An access ACL is the access control list for a specific file or directory A default ACL can only be associated with a directory if a file within the directory does not have an access ACL it uses the rules of the default ACL for the directory Default ACLs are optional 104 Chapter 14 Access Control Lists ACLs can be configured 1 Per user 2 Per group 3 Via the effective rights mask 4 For users not in the user group for the file The setfac1 utility sets ACLs for files and directories Use the m option to add or modify the ACL of a file or directory setfacl m lt rules gt lt files gt Rules lt rules gt must be specified in the following formats Multiple rules can be specified in the same command if they are separated by commas u lt uid gt lt perms gt Sets the access ACL for a user The user name or UID may be specified The user may be any valid user on the system g lt gid gt lt perms gt Sets the access ACL for a group The group name or GID may be specified The group may be any valid gro
339. ot loader from a rescue environment refer to Section 5 2 1 Reinstalling the Boot Loader 5 1 2 Hardware Software Problems This category includes a wide variety of different situations Two examples include failing hard drives and specifying an invalid root device or kernel in the boot loader configuration file If either of these occur you might not be able to reboot into Red Hat Enterprise Linux However if you boot into one of the system recovery modes you might be able to resolve the problem or at least get copies of your most important files 5 1 3 Root Password What can you do if you forget your root password To reset it to a different password boot into rescue mode or single user mode and use the passwd command to reset the root password 54 Chapter 5 Basic System Recovery 5 2 Booting into Rescue Mode Rescue mode provides the ability to boot a small Red Hat Enterprise Linux environment entirely from CD ROM or some other boot method instead of the system s hard drive As the name implies rescue mode is provided to rescue you from something During normal oper ation your Red Hat Enterprise Linux system uses files located on your system s hard drive to do everything run programs store your files and more However there may be times when you are unable to get Red Hat Enterprise Linux running completely enough to access files on your system s hard drive Using rescue mode you can access the files stored on y
340. ou have more than one key pair configured you will be prompted for each one 3 When you log out your passphrase s will be forgotten You must execute these two commands each time you log in to a virtual console or open a terminal window 21 4 Additional Resources The OpenSSH and OpenSSL projects are in constant development and the most up to date informa tion for them is available from their websites The man pages for OpenSSH and OpenSSL tools are also good sources of detailed information 21 4 1 Installed Documentation e 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 21 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 21 4 3 Related Books Red Hat Enterprise Linux Reference Guide Learn the event sequence of an SSH connection review a list of configuration files and discover how SSH can be used for X forwarding Chapter 22 Network File System NFS Network File System NFS is a way to share files between machines on a network as if the files were located on the client s local hard
341. our system s hard drive even if you cannot actually run Red Hat Enterprise Linux from that hard drive To boot into rescue mode you must be able to boot the system using one of the following methods By booting the system from an installation boot CD ROM By booting the system from other installation boot media such as USB flash devices By booting the system from the Red Hat Enterprise Linux CD ROM 1 Once you have booted using one of the described methods add the keyword rescue as a kernel pa rameter For example for an x86 system type the following command at the installation boot prompt linux rescue You are prompted to answer a few basic questions including which language to use It also prompts you to select where a valid rescue image is located Select from Local CD ROM Hard Drive NFS image FTP or HTTP The location selected must contain a valid installation tree and the installation tree must be for the same version of Red Hat Enterprise Linux as the Red Hat Enterprise Linux CD ROM 1 from which you booted If you used a boot CD ROM or other media to start rescue mode the installation tree must be from the same tree from which the media was created For more information about how to setup an installation tree on a hard drive NFS server FTP server or HTTP server refer to the Red Hat Enterprise Linux Installation Guide If you select a rescue image that does not require a network connection you are asked whether
342. owing Improved connection durability thus less NFS stale file handles messages Performance gain on heavily loaded networks because TCP acknowledges every packet unlike UDP which only acknowledges completion TCP has better congestion control than UDP which has none On a very congested network UDP packets are the first packets that are dropped This means that if NFS is writing data in 8K chunks all of that 8K must be retransmitted over UDP Because of TCP s reliability only parts of that 8K data are transmitted at a time Error detection When a TCP connection breaks due to the server being unavailable the client stops sending data and restarts the connection process once the server becomes available With UDP since it s connection less the client continues to pound the network with data until the server reestablishes a connection The main disadvantage is that there is a very small performance hit due to the overhead associated with the TCP protocol 22 2 4 Preserving ACLs The Red Hat Enterprise Linux 4 kernel provides ACL support for the ext3 file system and ext3 file systems mounted with the NFS or Samba protocols Thus if an ext3 file system has ACLs enabled for it and is NFS exported and if the NFS client can read ACLs they are used by the NFS client as well 22 3 Exporting NFS File Systems Sharing or serving files from an NFS server is known as exporting the directories The NFS Server Configuration T
343. ox next to Enable and enter the appropriate information for the authentication method Refer to Chapter 27 Authentication Configuration for more information about the options 2 7 Firewall Configuration The Firewall Configuration window is similar to the screen in the installation program and the Se curity Level Configuration Tool 36 Chapter 2 Kickstart Configurator Eile Help Basic Configuration Firewall Configuration Installation Method Security level Enable firewall Boot Loader Options Trusted devices Partition Information Network Configuration Authentication Firewall Configuration Trusted services WWW HTTP Display Configuration Package Selection O FTP Pre Installation Script SSH Post4nstallation Script O Telnet LI Mail SMTP Other ports 1029 tcp Figure 2 10 Firewall Configuration If Disable firewall is selected the system allows complete access to any active services and ports No connections to the system are refused or denied Selecting Enable firewall configures the system to reject incoming connections that are not in re sponse to outbound requests such as DNS replies or DHCP requests If access to services running on this machine is required you can choose to allow specific services through the firewall Only devices configured in the Network Configuration section are listed as available Trusted de vices Connections from any devices selected in the l
344. pace usage refer to Section 40 3 File Systems You must have the parted package installed to use the parted utility To start parted at a shell prompt as root type the command parted dev sda where dev sda is the device name for the drive you want to configure The parted prompt is displayed Type help to view a list of available commands If you want to create remove or resize a partition the device cannot be in use partitions cannot be mounted and swap space cannot be enabled The partition table should not be modified while in use because the kernel may not properly recognize the changes Data could be overwritten by writing to the wrong partition because the partition table and partitions mounted do not match The easiest way to achieve this it to boot your system in rescue mode Refer to Chapter 5 Basic System Recovery for instructions on booting into rescue mode When prompted to mount the file system select Skip Alternately if the drive does not contain any partitions in use system processes that use or lock the file system from being unmounted you can unmount them with the umount command and turn off all the swap space on the hard drive with the swapoff command Table 12 1 contains a list of commonly used parted commands The sections that follow explain some of them in more detail Perform a simple check of the file system cp from to Copy file system from one partition to another fromand to are the minor numbers of t
345. package log in as root and type the following command at a shell prompt rpm Uvh foo 1 0 1 i386 rpm If installation is successful the following output is displayed Preparing SAE AAA AA AE ARE AE FE AE AEE AE AEE E EAE AEA AE aE EE aE AEE aE aE aE AEA EE 1005 1 foo FEAE AE AE AE E AE AE AE AE AE E AE E AE E AE HE AE E AE E AE AE AE AEE AE aE EAE aE aE aE AE 100 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 The signature of a package is checked automatically when installing or upgrading a package The signature confirms that the package was signed by an authorized party For example if the verification of the signature fails an error message such as the following is displayed Chapter 15 Package Management with RPM 113 error V3 DSA signature BAD key ID 0352860f If it is a new header only signature an error message such as the following is displayed error Header V3 DSA signature BAD key ID 0352860f If you do not have the appropriate key installed to verify the signature the message contains the word NOKEY such as warning V3 DSA signature NOKEY key ID 0352860f Refer to Section 15 3 Checking a Package s Signature for more information on checking a package s signature waming If you are installing a kernel package you should use rpm ivh instead Refer to Chapter 37 Manually Upgrading the Kernel for de
346. pcontrol Configures what data is collected Refer to Section 41 2 Configuring OProfile for details Retrieves profile data Refer to Section 41 5 1 Using opreport for details oprofiled Runs as a daemon to periodically write sample data to disk Table 41 1 OProfile Commands 41 2 Configuring OProfile Before OProfile can be run it must be configured At a minimum selecting to monitor the kernel or selecting not to monitor the kernel is required The following sections describe how to use the opcontrol utility to configure OProfile As the opcontrol commands are executed the setup op tions are saved to the root oprofile daemonrc file 41 2 1 Specifying the Kernel First configure whether OProfile should monitor the kernel This is the only configuration option that is required before starting OProfile All others are optional To monitor the kernel execute the following command as root opcontrol setup vmlinux usr lib debug lib modules uname r vmlinux Note The debuginfo package must be installed which contains the uncompressed kernel in order to monitor the kernel To configure OProfile not to monitor the kernel execute the following command as root opcontrol setup no vmlinux This command also loads the oprofile kernel module if it is not already loaded and creates the dev oprofile directory if it does not already exist Refer to Section 41 6 Understanding dev oprofile for details about
347. pe linux swap The changes start taking place as soon as you press Enter so review the command before executing to it 92 Chapter 12 Managing Disk Storage 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 12 1 2 2 Formating the Partition The partition still does not have a file system Create the file system sbin mkfs t ext3 dev sda6 waming Formatting the partition permanently destroys any data that currently exists on the partition 12 1 2 3 Labeling the Partition Next give the partition a label For example if the new partition is dev sda6 and you want to label it work e2label dev sda6 work By default the installation program uses the mount point of the partition as the label to make sure the label is unique You can use any label you want 12 1 2 4 Creating the Mount Point As root create the mount point mkdir work 12 1 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
348. pend the contents of the file ssh id_dsa pub to the file ssh authorized_keys on the other machine 4 Change the permissions of the authorized_keys file using the following command chmod 644 ssh authorized_keys Chapter 21 OpenSSH 167 5 If you are running GNOME skip to Section 21 3 4 4 Configuring ssh agent with GNOME If you are not running the X Window System skip to Section 21 3 4 5 Configuring ssh agent 21 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 1 of the SSH Protocol If you are only connecting between systems that use DSA you do not need an RSA version 1 3 or RSA version 1 5 key pair 1 To generate an RSA for version 1 3 and 1 5 protocol key pair type the following command at a shell prompt ssh keygen t rsal Accept the default file location ssh identity Enter a passphrase different from your account password Confirm the passphrase by entering it again The public key is written to ssh identity pub The private key is written to ssh identity Do not give anyone the private key 2 Change the permissions of your ssh directory and your key with the commands chmod 755 sshand chmod 644 ssh identity pub 3 Copy the contents of ssh identity pub into 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 f
349. perating System The operating system identifier to install on this client The list is populated from the network install instances created from the Network Installation Dialog Serial Console This option allows use of a serial console e Kickstart File The location of a kickstart file to use such as http server example com kickstart ks cfg This file can be created with the Kickstart Configurator Refer to Chapter 2 Kickstart Configurator for details Ignore the Snapshot name and Ethernet options They are only used for diskless environments For more information on configuring a diskless environment refer to Chapter 4 Diskless Environments for details 3 3 1 Command Line Configuration If the network server is not running X the pxeboot utility a part of the system config netboot package can be used to add hosts which are allowed to connect to the PXE server pxeboot a K lt kickstart gt O lt os identifier gt r lt value gt lt host gt The following list explains the options e a Specifies that a host is to be added e K lt kickstart gt W The location of the kickstart file if available O lt os identifier gt Specifies the operating system identifier as defined in Section 3 2 PXE Boot Configuration e r lt value gt Specifies the ram disk size e lt host gt Specifies the IP address or hostname of the host to add For more information on command line options available for the px
350. ple examine the following lines misc export speedy example com rw sync misc export speedy example com rw sync The first line grants users from speedy example com read write access and denies all other users The second line grants users from speedy example com read only access the default and allows the rest of the world read write access Each time you change etc exports you must inform the NFS daemon of the change or reload the configuration file with the following command sbin service nfs reload 22 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 wildcards Use the or character to specify a string match Wildcards are not to be used with IP addresses however they may accidentally work if reverse DNS lookups fail When specifying wildcards in fully qualified domain names dots are not included in the wildcard For example example com includes one example com but does not include one two example com IP networks Use a b c d z where a b c d is the network and z is the number of bits in the netmask for example 192 168 0 0 24 Another acceptable format is a b c d netmask where a b c d is the network and netmask is the netmask for example 192 168 100 8 255 255 255 0 Netgroups In the
351. ple if you want to execute the command 1s usr share doc on the remote machine penguin example net type the following command at a shell prompt ssh penguin example net ls usr share doc After you enter the correct password the contents of the remote directory usr share doc will be displayed and you will return to your local shell prompt 21 3 2 Using the scp Command The scp command can be used to transfer files between machines over a secure encrypted connection It is similar to rcp The general syntax to transfer a local file to a remote system is as follows scp lt localfile gt username tohostname lt remotefile gt The lt localfile gt specifies the source including path to the file such as var log maillog The lt remotefile gt specifies the destination which can be a new filename such as Chapter 21 OpenSSH 165 tmp hostname maillog For the remote system if you do not have a preceding the path will be relative to the home directory of username typically home username To transfer the local file shadowman to the home directory of your account on penguin example net type the following at a shell prompt replace username with your username scp shadowman username penguin example net shadowman This will transfer the local file shadowman to home username shadowman on penguin example net Alternately you can leave off the final shadowman in the scp command The general syntax to transfer a remote file to t
352. port does not associate samples for inline functions properly opreport uses a simple address range mechanism to determine which function an address is in Inline function samples are not attributed to the inline function but rather to the function the inline function was inserted into OProfile accumulates data from multiple runs OProfile is a system wide profiler and expects processes to start up and shut down multiple times Thus samples from multiple runs accumulate Use the command opcontrol reset to clear out the samples from previous runs Non CPU limited performance problems OProfile is oriented to finding problems with CPU limited processes OProfile does not identify processes that are asleep because they are waiting on locks or for some other event to occur for example an I O device to finish an operation 41 1 Overview of Tools Table 41 1 provides a brief overview of the tools provided with the oprofile package op_help Displays available events for the system s processor along with a brief description of each op_import Converts sample database files from a foreign binary format to the native format for the system Only use this option when analyzing a sample database from a different architecture 308 Chapter 41 OProfile Command opannotate Creates annotated source for an executable if the application was compiled with debugging symbols Refer to Section 41 5 3 Using opannotate for details o
353. program prompting the user for an answer to the related item just as the user would be prompted during a typical installation Once the answer is given the installation continues 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 the installation Keyboard setup The upgrade keyword Boot loader configuration If any other items are specified for an upgrade those items are ignored note that this includes package selection 1 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 use the Kickstart Configurator application Refer to Chapter 2 Kickstart Configurator for details f Note If the option is followed by an equals mark a value must be specified after it In the example commands options in brackets are optional arguments for the command autopart optional Automatically create partitions 1 GB or more root partition a swap partition and an appropriate boot partition for the architecture One or more of the default partition sizes can be redefined with the part directive autostep optional Similar to interactive except it goes to the next screen fo
354. r directive Group sets the group under which the server answers requests The default group is also apache 25 5 Performance Tuning Click on the Performance Tuning tab to configure the maximum number of child server processes you want and to configure the Apache HTTP Server options for client connections The default settings for these options are appropriate for most situations Altering these settings may affect the overall performance of your Web server Main Virtual Hosts Server Performance Tuning Servers gt Max Number of Connections 150 s Connections Connection Timeout 300 O Allow unlimited requests per connection Max requests per connection 100 x Requests per Connection Allow Persistent Connections Timeout for next Connection F OK Cancel T Heip Figure 25 11 Performance Tuning Set Max Number of Connections to the maximum number of simultaneous client requests that the server can handle For each connection a child ht tpa process is created After this maximum number of processes is reached no one else can 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 corresponds to the MaxClients directive Connection Timeout defines in seconds the amount of time that your server waits for receipts and transmissions during communications Specifi
355. r Code column To override this default configuration select the error code and click the Edit button Choose Default to display the default short error message Choose URL to redirect the client to an external URL and enter a complete URL including the http in the Location field Choose File to redirect the client to an internal URL and enter a file location under the document root for the Web server The location must begin the a slash and be relative to the Document Root For example to redirect a 404 Not Found error code to a webpage that you created in a file called 404 html copy 404 html to DocumentRoot error 404 html In this case DocumentRoot is the Document Root directory that you have defined the default is var www htm1 If the Document Root is left as the default location the file should be copied to var www error 404 html Then choose File as the Behavior for 404 Not Found error code and enter error 404 htm1 as the Location From the Default Error Page Footer menu you can choose one of the following options Show footer with email address Display the default footer at the bottom of all error pages along with the email address of the website maintainer specified by the ServerAdmin directive Refer to Section 25 3 1 1 General Options for information about configuring the ServerAdmin directive Show footer Display just the default footer at the bottom of error pages No footer Do not display a f
356. r Configuration Tool select the printer from the list click Edit click the Driver tab select a different print driver and then apply the changes 34 7 1 Confirming Printer Configuration The last step is to confirm your printer configuration Click Finish to add the print queue if the settings are correct Click Back to modify the printer configuration Click the Apply button in the main window to save your changes and restart the printer daemon After applying the changes print a test page to ensure the configuration is correct Refer to Section 34 8 Printing a Test Page for details If you need to print characters beyond the basic ASCII set including those used for languages such as Japanese you must review your driver options and select Prerender Postscript Refer to Section 34 9 Modifying Existing Printers for details You can also configure options such as paper size if you edit the print queue after adding it 266 Chapter 34 Printer Configuration 34 8 Printing a Test Page After you have configured your printer you should print a test page to make sure the printer is func tioning properly To print a test page select the printer that you want to try out from the printer list then select the appropriate test page from the Test pulldown menu If you change the print driver or modify the driver options you should print a test page to test the different configuration Action Test Help B Q CUPS test page New QUS Le
357. r ext2 file system on a diskette and you boot from the Red Hat Enterprise Linux CD ROM 1 An alternate boot command is to boot off the Red Hat Enterprise Linux CD ROM 1 and have the kickstart file on a vfat or ext2 file system on a diskette To do so enter the following command at the boot prompt linux ks hd fd0 ks cfg With Driver Disk If you need to use a driver disk with kickstart specify the dd option as well For example to boot off a boot diskette and use a driver disk enter the following command at the boot prompt linux ks floppy dd Boot CD ROM If the kickstart file is on a boot CD ROM as described in Section 1 8 1 Creating Kickstart Boot Media insert the CD ROM into the system boot the system and enter the following command at the boot prompt where ks cfg is the name of the kickstart file linux ks cdrom ks cfg Other options to start a kickstart installation are as follows ks nfs lt server gt lt path gt The installation program looks for the kickstart file on the NFS server lt server gt as file lt path gt The installation program uses 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 looks for the kickstart file on the HTTP server lt server gt as file lt p
358. r options 267 Effective Filter Locale 268 GhostScript pre filtering 268 Media Source 268 Page Size 268 Prerender Postscript 267 edit driver 267 edit existing printer 266 exporting settings 268 GNOME Print Manager 270 change printer settings 270 importing settings 268 IPP printer 259 JetDirect printer 263 local printer 258 managing print jobs 270 modifying existing printers 266 networked CUPS IPP printer 259 notification icon 271 Novell NetWare NCP printer 263 printing from the command line 272 remote LPD printer 260 rename existing printer 267 Samba SMB printer 261 save configuration to file 268 sharing 272 allowed hosts 273 system wide options 273 test page 266 text based application 257 viewing print spool 270 viewing print spool command line 271 Printer Configuration Tool see printer configuration printtool 328 see printer configuration processes 301 ps 301 PXE 43 PXE installations 43 adding hosts 45 boot message custom 47 configuration 43 DHCP configuration 47 50 Network Booting Tool 43 overview 43 performing 47 setting up the network server 43 pxeboot 46 pxeos 44 Q quotacheck 98 quotacheck command checking quota accuracy with 101 quotaoff 100 quotaon 100 R racoon 147 149 RAID 73 configuring software RAID during installation 77 explanation of 73 Hardware RAID 73 installing creating the boot partition 77 creating the mount point
359. r problems Issue the following command the kernel version may vary rpm ivh kernel 2 6 9 5 EL lt arch gt rpm If the system is a multi processor system install the kernel smp packages as well the kernel version may vary rpm ivh kernel smp 2 6 9 5 EL lt arch gt rpm If the system is i686 based and contains more than 4 GB of RAM install the kernel hugemem package built for the i686 architecture as well the kernel version might vary rpm ivh kernel hugemem 2 6 9 5 EL i686 rpm The next step is to verify that the initial RAM disk image has been created Refer to Section 37 5 Verifying the Initial RAM Disk Image for details 37 5 Verifying the Initial RAM Disk Image If the system uses the ext3 file system a SCSI controller or uses labels to reference partitions in etc f stab an initial RAM disk is needed The initial RAM disk allows a modular kernel to have access to modules that it might need to boot from before the kernel has access to the device where the modules normally reside On the Red Hat Enterprise Linux architectures other than IBM eServer iSeries the initial RAM disk can be created with the mkinitrd command However this step is performed automatically if the kernel and its associated packages are installed or upgraded from the RPM packages distributed by Red Hat Inc thus it does not need to be executed manually To verify that it was created use the Chapter 37 Manually Upgrading the Kernel 289 co
360. r you It is used mostly for debug ging auth or authconfig required Sets up the authentication options for the system It is similar to the authconfig command which can be run after the install By default passwords are normally encrypted and are not shadowed Chapter 1 Kickstart Installations 3 enablemd5 Use md5 encryption for user passwords enablenis Turns on NIS support By default enablenis uses whatever domain it finds on the network A domain should almost always be set by hand with the nisdomain option nisdomain NIS domain name to use for NIS services nisserver Server to use for NIS services broadcasts by default useshadow or enableshadow Use shadow passwords enableldap Turns on LDAP support in etc nsswitch conf allowing your system to retrieve infor mation about users UIDs home directories shells etc from an LDAP directory To use this option you must install the nss_ldap package You must also specify a server and a base DN distinguished name with l1dapserver and ldapbasedn enableldapauth Use LDAP as an authentication method This enables the pam_1ldap 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 e
361. ransport Agent MTA Configuration A Mail Transport Agent MTA is essential for sending email A Mail User Agent MUA such as Evolution Mozilla Mail Thunderbird and Mutt is used to read and compose email When a user sends an email from an MUA the message is handed off to the MTA which sends the message through a series of MTAs until it reaches its destination Even if a user does not plan to send email from the system some automated tasks or system programs might use the bin mail command to send email containing log messages to the root user of the local system Red Hat Enterprise Linux 4 provides three MTAs Sendmail Postfix and Exim If all three are in stalled sendmail is the default MTA The Mail Transport Agent Switcher allows for the selection of either sendmail postfix or exim as the default MTA for the system The system switch mail RPM package must be installed to use the text based version of the Mail Transport Agent Switcher program If you want to use the graphical version the system switch mail gnome package must also be installed For more information on installing RPM packages refer to Part III Package Management To start the Mail Transport Agent Switcher select Applications the main menu on the panel gt Preferences gt More Preferences gt Mail Transport Agent Switcher or type the command system switch mail at a shell prompt for example in an XTerm or GNOME terminal The program automatically dete
362. raphical version of the Network Booting Tool you must be running the X Window System have root privileges and have the system config netboot RPM package installed To start the Network Booting Tool from the desktop go to Applications the main menu on the panel gt System Settings gt Server Settings gt Network Booting Service Or type the command system config netboot at a shell prompt for example in an XTerm or a GNOME terminal 44 Chapter 3 PXE Network Installations If starting the Network Booting Tool for the first time select Network Install from the First Time Druid Otherwise select Configure gt Network Installation from the pulldown menu and then click Add The dialog in Figure 3 1 is displayed Operating system identifier rhel4 as Description RHEL 4AS Select protocol for installation NFS Kickstart http www example com ks ks cfg Software Server server example com Location misc RHEL4 AS i386 tree Anonymous FTP User Password Cancel 2 OK Figure 3 1 Network Installation Setup Operating system identifier Provide a unique name using one word to identify the Red Hat Enterprise Linux version and variant It is used as the directory name in the t tpboot linux install directory Description Provide a brief description of the Red Hat Enterprise Linux version and variant Selects protocol for installation Selects NFS FTP
363. rective 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 file name do 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 the verbosity of the error messages in the error logs 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 automatically resolves the IP address for each connection which requests a document from your Web server Resolving the IP address means that your server makes one or more connections to the DNS in order to find out the hostname that corresponds to a particular IP address If you choose Double Reverse Lookup your server performs 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
364. remove a swap volume group assuming dev VolGroup00 LogVo102 is the swap volume you want to remove 1 Disable swapping for the associated logical volume swapoff v dev VolGroup00 LogVol02 2 Remove the LVM2 logical volume of size 512 MB lvm lvremove dev VolGroup00 LogVol02 3 Remove the following entry from the etc fstab file 88 Chapter 11 Swap Space dev VolGroup00 LogVol02 swap swap defaults 00 4 Test that the logical volume has been extended properly cat proc swaps free 11 3 3 Removing a Swap File To remove a swap file 1 At a shell prompt as root execute the following command to disable the swap file where swapf ile is the swap file swapoff v swapfile 2 Remove its entry from the etc fstab file 3 Remove the actual file rm swapfile 11 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 Chapter 12 Managing Disk Storage Introduction to different methods 12 1 Standard Partitions using parted Many users need to view the existing partition table change the size of the partitions remove parti tions or add partitions from free space or additional hard drives The utility parted allows users to perform these tasks This chapter discusses how to use parted to perform file system tasks If you want to view the system s disk space usage or monitor the disk s
365. repquota home produces this output Report for user quotas on device dev mapper VolGroup00 LogVol102 Block grace time 7days Inode grace time 7days Block limits File limits User used soft hard grace used soft hard grace root ga 36 0 0 4 0 0 kristin a 540 0 0 125 0 0 testuser 440400 500000 550000 37418 0 0 To view the disk usage report for all option a quota enabled file systems use the command repquota a While the report is easy to read a few points should be explained The displayed after each user is a quick way to determine whether the block or inode limits have been exceeded If either soft limit is exceeded a appears in place of the corresponding the first represents the block limit and the second represents the inode limit The grace columns are normally blank If a soft limit has been exceeded the column contains a time specification equal to the amount of time remaining on the grace period If the grace period has expired none appears in its place 13 2 3 Keeping Quotas Accurate Whenever a file system is not unmounted cleanly due to a system crash for example it is necessary to run quotacheck However quotacheck can be run on a regular basis even if the system has not crashed Running the following command periodically keeps the quotas more accurate the options used have been described in Section 13 1 1 Enabling Quotas quotacheck avug The easiest way to run it periodically is to u
366. reserved across upgrades so you do not lose your customizations There are no special upgrade files needed to upgrade a package because the same RPM file is used to install and upgrade the package on your system Powerful Querying RPM is designed to provide powerful querying options You can do searches through your entire database for packages or just for certain files You can also easily find out what package a file belongs to and from where the package came The files an RPM package contains are in a com pressed archive with a custom binary header containing useful information about the package and its contents allowing you to query individual packages quickly and easily System Verification Another powerful feature is the ability to verify packages If you are worried that you deleted an important file for some package verify the package You are notified of any anomalies At that 112 Chapter 15 Package Management with RPM point you can reinstall the package if necessary Any configuration files that you modified are preserved during reinstallation Pristine Sources A crucial design goal was to allow the use of pristine software sources as distributed by the original authors of the software With RPM you have the pristine sources along with any patches that were used plus complete build instructions This is an important advantage for several rea sons For instance if a new version of a program comes out you do not necess
367. rnatively complete the Red Hat registration process online at http www redhat com register 4 1 Provide a Red Hat Login If you do not have an existing Red Hat login you can create one when prompted during the Setup Agent or online at https www redhat com apps activate newlogin html A Red Hat login enables your access to Software updates errata and maintenance via Red Hat Network Red Hat technical support resources documentation and Knowledgebase If you have forgotten your Red Hat login you can search for your Red Hat login online at https rhn redhat com help forgot_password pxt vi Introduction 4 2 Provide Your Subscription Number Your subscription number is located in the package that came with your order If your package did not include a subscription number your subscription was activated for you and you can skip this step You can provide your subscription number when prompted during the Setup Agent or by visiting http www redhat com register 4 3 Connect Your System The Red Hat Network Registration Client helps you connect your system so that you can begin to get updates and perform systems management There are three ways to connect 1 During the Setup Agent Check the Send hardware information and Send system package list options when prompted 2 After the Setup Agent has been completed From Applications the main menu on the panel go to System Tools then select Red Hat Network
368. rnel devel 2 6 9 5 EL kernel utils 2 6 9 5 EL kernel doc 2 6 9 5 EL kernel smp 2 6 9 5 EL kernel smp devel 2 6 9 5 EL kernel hugemem devel 2 6 9 5 EL From the output determine which packages need to be download for the kernel upgrade For a single processor system the only required package is the kernel package Refer to Section 37 1 Overview of Kernel Packages for descriptions of the different packages In the file name each kernel package contains the architecture for which the package was built The format is kernel lt variant gt lt version gt lt arch gt rpm where lt variant gt is smp utils or so forth The lt arch gt is one of the following e x86_64 for the AMD64 architecture e ia64 for the Intel Itanium architecture ppc 4 for the IBM eServer pSeries architecture ppc 4 for the IBM eServer iSeries architecture e s390 for the IBM S 390 architecture s390x for the IBM eServer zSeries architecture x86 variant The x86 kernels are optimized for different x86 versions The options are as follows i686 for Intel Pentium II Intel Pentium III Intel Pentium 4 AMD Athlon and AMD Duron systems 37 3 Downloading the Upgraded Kernel There are several ways to determine if an updated kernel is available for the system e Security Errata Go to the following location for information on security errata including kernel upgrades that fix security issues http w
369. roc swaps commands to verify how much and where swap is in use The best way to achieve swap space modifications is to boot your system in rescue mode and then follow the instructions for each scenario in the remainder of this chapter Refer to Chapter 5 Basic System Recovery for instructions on booting into rescue mode When prompted to mount the file system select Skip 11 2 Adding Swap Space Sometimes it is necessary to add more swap space after installation For example you may upgrade the amount of RAM in your system from 128 MB to 256 MB but there is only 256 MB of swap space It might be advantageous to increase the amount of swap space to 512 MB if you perform memory intense operations or run applications that require a large amount of memory 86 Chapter 11 Swap Space You have three options create a new swap partition create a new swap file or extend swap on an existing LVM2 logical volume It is recommended that you extend an existing logical volume 11 2 1 Extending Swap on an LVM2 Logical Volume To extend an LVM2 swap logical volume assuming dev VolGroup00 LogVo101 is the volume you want to extend j Disable swapping for the associated logical volume swapoff v dev VolGroup00 LogVol01 2 Resize the LVM2 logical volume by 256 MB lvm lvresize dev VolGroup00 LogVol01 L 256M 3 Format the new swap space mkswap dev VolGroup00 LogVol01 4 Enable the extended logical volume swapon va 5
370. roduction to Sys tem Administration Primary Writer Maintainer of the Release Notes Contributing Writer to the Red Hat Enterprise Linux Installation Guide for x86 Itanium AMD64 and Intel Extended Memory 64 Technology Intel EM64T Karsten Wade Primary Writer Maintainer of the Red Hat SELinux Guide Contributing Writer to the Red Hat Enterprise Linux System Administration Guide Andrius T Benokraitis Primary Writer Maintainer of the Red Hat Enterprise Linux Reference Guide Co writer Co maintainer of the Red Hat Enterprise Linux Security Guide Contributing Writer to the Red Hat Enterprise Linux System Administration Guide Paul Kennedy Primary Writer Maintainer of the Red Hat GFS Administrator s Guide Contributing Writer to the Red Hat Cluster Suite Configuring and Managing a Cluster Mark Johnson Primary Writer Maintainer of the Red Hat Desktop Deployment Guide Contributing Writer of Red Hat Network documentation Melissa Goldin Primary Writer Maintainer of the Red Hat Enterprise Linux Step By Step Guide Contributing Writer of Red Hat Network Documentation Lucy Ringland Red Hat Enterprise Linux Documentation Editor The Red Hat Localization Team consists of the following people Amanpreet Singh Alam Punjabi translations Jean Paul Aubry French translations David Barzilay Brazilian Portuguese translations Runa Bhattacharjee Bengali translations Chester Cheng Traditional Chinese trans
371. rom the list and click Delete The alert icon is displayed to the left of the lines that contains any of the alert words Log Files Alerts Wamings Alerts Show alert icon for the following key words fail Add denied rejected Delete oops segfault segmentation Figure 36 4 Alerts To add warning words select Edit gt Preferences from the pull down menu and click on the Warn ings tab Click the Add button to add a warning word To delete a warning word select the word from the list and click Delete 284 Chapter 36 Log Files The warning icon is displayed to the left of the lines that contains any of the warning words Figure 36 5 Warning Log Files Alerts Warnings Warnings A Show warning icon for the following key words wam Ada Delete x Close Chapter 37 Manually Upgrading the Kernel The Red Hat Enterprise Linux kernel is custom built by the Red Hat kernel team to ensure its integrity and compatibility with supported hardware Before Red Hat releases a kernel it must first pass a rigorous set of quality assurance tests Red Hat Enterprise Linux kernels are packaged in RPM format so that they are easy to upgrade and verify using the Red Hat Update Agent or the up2date command The Red Hat Update Agent automatically queries the Red Hat Network servers and determines whi
372. ron is a daemon that can be used to schedule the execution of recurring tasks according to a combi nation of the time day of the month month day of the week and week Cron assumes that the system is on continuously If the system is not on when a task is scheduled it is not executed To schedule one time tasks refer to Section 35 2 At and Batch To use the cron service the vixie cron RPM package must be installed and the crond service must be running To determine if the package is installed use the rpm q vixie cron command To determine if the service is running use the command sbin service crond status 35 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 0l 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 SHELL variable tells the system which shell environment to use in this example the bash shell while the PATH variable defines the path used to execute commands The output of the cron tasks are emailed to the username defined with the MAILTO variable If the MAILTO variable is defined as an empty string MAILTO email is not sent The HOME variable can b
373. rth 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 28 3 Defining the Console The pam_console so module uses the etc security console perms file to determine the permissions for users at the system console The syntax of the file is very flexible you can edit the file so that these instructions no longer apply However the default file has a line that looks like this lt console gt tty 0 9 0 9 vc 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 ora 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 vc 0 9 0 9 0 9 0 9 0 9 dev ttyS1 28 4 Making Files Accessible From the Console In etc security console perms there is a section with lines like lt floppy gt dev fd 0 1 dev floppy mnt floppy lt sound gt dev dsp dev audio dev midi dev mixer dev sequencer de
374. rtitions Chapter 2 Kickstart Configurator To edit an existing partition select the partition from the list and click the Edit button The same Partition Options window appears as when you chose to add a partition as shown in Figure 2 5 except it reflects the values for the selected partition Modify the partition options and click OK To delete an existing partition select the partition from the list and click the Delete button 2 4 1 1 Creating Software RAID Partitions To create a software RAID partition use the following steps 1 Click the RAID button 2 Select Create a software RAID partition 3 Configure the partitions as previously described except select Software RAID as the file system type Also you must specify a hard drive on which to make the partition or specify an existing partition to use Mount Point y File System Type software RAID x Size MB 2048 lt Additional Size Options Fixed size Grow to maximum of MB 1 Fill all unused space on disk Use recommended swap size C Force to be a primary partition asprimary 7 Make partition on specific drive ondisk Drive sdal for example hda or sdc K X Cancel Qox Figure 2 6 Creating a Software RAID Partition Chapter 2 Kickstart Configurator 33 Repeat these steps to create as many partitions as needed for your RAID setup All of yo
375. rver It is used in small to large networks 225 C Enable LDAP Support Configure LDAF C Enable Winbind Support Use Shadow Passwords E Use MDS Passwords R Cancel 2 OK Figure 27 2 Authentication The following explains what each option configures Enable Kerberos Support Select this option to enable Kerberos authentication Click the Con figure Kerberos button to configure Realm Configure the realm for the Kerberos server The realm is the network that uses Ker beros composed of one or more KDCs and a potentially large number of clients KDC Define the Key Distribution Center KDC which is the server that issues Kerberos tickets Admin Servers Specify the administration server s running kadmind The krb5 1libs and krb5 workstation packages must be installed for this option to work Refer to the Red Hat Enterprise Linux Reference Guide for more information on Kerberos Enable LDAP Support Select this option to have standard PAM enabled applications use LDAP for authentication Click the Configure LDAP button to specify the following Use TLS to encrypt connections Use Transport Layer Security to encrypt passwords sent to the LDAP server LDAP Search Base DN Retrieve user information by its Distinguished Name DN LDAP Server Specify the IP address of the LDAP server The openldap clients package must be installed for this option t
376. ry Refer to Section 18 12 3 Testing the IPsec Connection to determine if the IPsec connection has been successfully established 18 12 3 Testing the IPsec Connection Use the tcpdump utility to view the network packets being transfered between the hosts or networks and verify that they are encrypted via IPsec The packet should include an AH header and should be shown as ESP packets ESP means it is encrypted For example issue the following command as root tcpdump 17 13 20 617872 pinky example com gt ijin example com AH spi 0x0aaa749f seq 0x335 ESP spi 0x0ec044le seq 0x335 DF The tcpdump command outputs live network traffic A few seconds after starting tcpdump manually kill the process by pressing Ctrl C You should see similar ESP packets signifying a working IPsec connection as displayed in the previous example An advanced IPsec test would require four systems which would fulfill a full multi homed IPsec network but is not discussed here Chapter 18 Network Configuration 151 18 12 4 Starting and Stopping the Connection If the IPsec connection was not configured to activate on boot start and stop it as root via the command line To start the connection execute the following command as root on each host for host to host IPsec or each IPsec router for network to network IPsec replace lt ipsec nick gt with the one word nickname configured earlier such as ipsec0 sbin ifup lt ipsec nick gt T
377. s gt Default Printer After adding the printer s the settings can be edited by selecting the printer from the printer list and clicking the Edit button The tabbed window shown in Figure 34 12 is displayed The window contains the current values for the selected printer Make any necessary changes and click OK Click Apply in the main Printer Configuration Tool window to save the changes and restart the printer daemon Chapter 34 Printer Configuration 267 Queue name Queue type Queue options Printer driver Driver options This is the name of the queue It must begin with a letter and contain no spaces Name printer About This is the description of the printer Short description my printer T Help 3 Cancel 2 OK Figure 34 12 Editing a Printer 34 9 1 Queue Name To rename a printer or change its short description change the value in the Queue name tab Click OK to return to the main window The name of the printer should change in the printer list Click Apply to save the change and restart the printer daemon 34 9 2 Queue Type The Queue type tab shows the queue type that was selected when adding the printer and its settings The queue type of the printer can be changed or just the settings After making modifications click OK to return to the main window Click Apply to save the changes and restart the printer daemon Depending on which que
378. s 182 reasons for using 177 share connecting to via the command line 184 connecting to with Nautilus 183 mounting 184 smbclient 184 starting the server 183 status of the server 182 stopping the server 183 syncing passwords with passwd 182 with Windows NT 4 0 2000 ME and XP 181 scp see OpenSSH secure server accessing 220 books 221 certificate authorities 215 choosing a CA 215 creation of request 217 moving it after an upgrade 214 pre existing 214 self signed 218 test vs signed vs self signed 215 testing 219 connecting to 220 explanation of security 213 installing 211 key generating 215 packages 211 port numbers 220 providing a certificate for 213 security explanation of 213 upgrading from 214 URLs 220 URLs for 220 websites 220 security 157 security level 329 see Security Level Configuration Tool Security Level Configuration Tool enabling and disabling 154 iptables service 155 saving 155 setting custom ports 155 trusted devices 155 trusted services 154 sendmail 297 services controlling access to 157 Services Configuration Tool 159 setfacl 104 Setup Agent via Kickstart 7 sftp see OpenSSH shadow passwords 225 shutdown disablingCtrlAltDel 231 single user mode 56 SMB 177 225 smb conf 177 smbclient 184 smbstatus 183 Software RAID see RAID ssh see OpenSSH ssh add 168 ssh agent 168 with GNOME 167 star 105 striping RAID fundamentals
379. s 80 creating the RAID devices 80 creating the RAID partitions 77 level 0 74 level 1 74 level 4 74 level 5 74 levels 74 reasons to use 73 Software RAID 73 RAM 303 rep 164 Red Hat Network 125 Red Hat Package Manager see RPM Red Hat RPM Guide 120 Red Hat Update Agent 125 registering your subscription v rescue mode definition of 54 utilities available 55 resize2fs 61 resolution 243 RHN see Red Hat Network rmmod 294 RPM 111 additional resources 120 book about 120 checking package signatures 117 dependencies 114 design goals 111 determining file ownership with 119 documentation with 119 file conflicts resolving 113 finding deleted files with 118 freshen 115 freshening packages 115 GnuPG 117 graphical interface 121 installing 112 with Package Management Tool 122 mdS5sum 117 preserving configuration files 115 querying 116 querying for file list 119 querying uninstalled packages 119 tips 118 uninstalling 114 with Package Management Tool 123 upgrading 115 using 112 verifying 117 website 120 RSA keys generating 166 RSA Version keys generating 167 runlevel 1 56 runlevels 157 S Samba 177 additional resources 185 configuration 177 181 default 177 smb conf 177 encrypted passwords 182 findsmb 184 graphical configuration 177 adding a share 180 configuring server settings 178 managing Samba users 179 list of active connections 183 pam_smbpas
380. s 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 is used so that users can report a problem to the server s administrator The default value is root localhost Use the Available Addresses area to define the ports on which the server accepts incoming requests This option corresponds to the Listen directive in httpd conf By default Red Hat configures 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 25 2 appears 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 accepts connections in the Address field Only specify one IP address per port number To specify more than one IP address with the same port number create an entry for each IP address If at all possible use an IP address instead of a domain name to prevent a DNS lookup failure Refer to http httpd apache org docs 2 0 dns caveats html for more information about Issues Regarding DNS and Apache Entering an asterisk in the Address field is the same as choosing Listen to all addresses Clicking the Edit button in the Available Addresses frame shows the same window as the Add button except with the fields populated for the select
381. s an overview of file systems refer to the Red Hat Enterprise Linux Reference Guide If you need security information refer to the Red Hat Enterprise Linux Security Guide 1 Changes To This Manual This manual has been reorganized for clarity and updated for the latest features of Red Hat Enterprise Linux 4 Some of the changes include Updated Kernel Modules and Manually Updating the Kernel Chapters The Kernel Modules andthe Upgrading the Kernel Manually chapters include updated information in regards to the 2 6 kernel Special thanks to Arjan van de Ven for his hard work in helping to complete this chapter An Updated Network File System NFS Chapter The Network File System NFS chapter has been revised and reorganized to include NFSv4 Special thanks to Steve Dickson for his hard work in helping to complete this chapter ii Introduction An Updated OProfile Chapter The OProfile chapter has been revised and reorganized to include updated information in regards to the 2 6 kernel Special thanks to Will Cohen for his hard work in helping to complete this chapter An Updated X Window System Chapter The X Window System chapter has been revised to include information on the X11R6 8 release developed by the X Org team Before reading this guide you should be familiar with the contents of the Red Hat Enterprise Linux Installation Guide concerning installation issues the Red Hat Enterprise Linux Introduction to System Administrati
382. s attached Path The path to the print queue on the remote machine Click Forward to continue Next select the printer type Refer to Section 34 7 Selecting the Printer Model and Finishing for de tails Important The networked IPP print server must allow connections from the local system Refer to Section 34 13 Sharing a Printer for more information 34 3 Adding a Remote UNIX LPD Printer To add a remote UNIX printer such as one attached to a different Linux system on the same net work click the New button in the main Printer Configuration Tool window The window shown in Figure 34 2 appears Click Forward to proceed In the window shown in Figure 34 3 enter a unique name for the printer in the Name text field The printer name cannot contain spaces and must begin with a letter The printer name may contain letters numbers dashes and underscores _ Optionally enter a short description for the printer which can contain spaces Chapter 34 Printer Configuration 261 Select Networked UNIX LPD from the Select a queue type menu and click Forward Select a queue type Networked UNIX LPD z Server Queue servername example com pl is Help Cancel lt 4 Back gt Forward Figure 34 6 Adding a Remote LPD Printer Text fields for the following options appear Server The hostname or IP address of the remote machine to which the printer i
383. s attached Queue The remote printer queue The default printer queue is usually 1p Click Forward to continue Next select the printer type Refer to Section 34 7 Selecting the Printer Model and Finishing for de tails important The remote print server must accept print jobs from the local system 34 4 Adding a Samba SMB Printer To add a printer which is accessed using the SMB protocol such as a printer attached to a Microsoft Windows system click the New button in the main Printer Configuration Tool window The win dow shown in Figure 34 2 appears Click Forward to proceed In the window shown in Figure 34 3 enter a unique name for the printer in the Name text field The printer name cannot contain spaces and must begin with a letter The printer name may contain letters numbers dashes and underscores _ Optionally enter a short description for the printer which can contain spaces Select Networked Windows SMB from the Select a queue type menu and click Forward If the printer is attached to a Microsoft Windows system choose this queue type 262 Chapter 34 Printer Configuration Select a queue type Networked Windows SMB T Heip 3 Cancel lt d Back D Forward Figure 34 7 Adding a SMB Printer As shown in Figure 34 7 SMB shares are automatically detected and listed Click the arrow beside each share n
384. s for libraries kernel generate per application profiles for the kernel and kernel modules e all generate per application profiles for libraries and per application profiles for the kernel and kernel modules If separate library is used the sample file name includes the name of the executable as well as the name of the library 312 Chapter 41 OProfile 41 3 Starting and Stopping OProfile To start monitoring the system with OProfile execute the following command as root opcontrol start Output similar to the following is displayed Using log file var lib oprofile oprofiled log Daemon started Profiler running The settings in root oprofile daemonrc are used The OProfile daemon oprofiled is started it periodically writes the sample data to the var lib oprofile samples directory The log file for the daemon is located at var lib oprofile oprofiled log To stop the profiler execute the following command as root opcontrol shutdown 41 4 Saving Data Sometimes it is useful to save samples at a specific time For example when profiling an executable it may be useful to gather different samples based on different input data sets If the number of events to be monitored exceeds the number of counters available for the processor multiple runs of OProfile can be used to collect data saving the sample data to different files each time To save the current set of sample files execute the following com
385. s in sections 1 and 5 The man page in section 1 contains an overview of the crontab file The man page in section 5 contains the format for the file and some example entries e usr share doc at lt version gt timespec contains more detailed information about the times that can be specified for cron jobs at man page description of at and batch and their command line options 280 Chapter 35 Automated Tasks Chapter 36 Log Files Log files are files that contain messages about the system including the kernel services and appli cations running on it There are different log files for different information For example there is a default system log file a log file just for security messages and a log file for cron tasks Log files can be very useful when trying to troubleshoot a problem with the system such as trying to load a kernel driver or when looking for unauthorized log in attempts to the system This chapter discusses where to find log files how to view log files and what to look for in log files Some log files are controlled by a daemon called syslogd A list of log messages maintained by syslogd can be found in the etc syslog conf configuration file 36 1 Locating Log Files Most log files are located in the var 1log directory Some applications such as httpd and samba have a directory within var 1og for their log files You may notice multiple files in the log file directory with numbers after them Thes
386. se Linux refer to the following resources 34 14 1 Installed Documentation map lpr The manual page for the 1pr command that allows you to print files from the command line man lprm The manual page for the command line utility to remove print jobs from the print queue man mpage The manual page for the command line utility to print multiple pages on one sheet of paper man cupsd The manual page for the CUPS printer daemon man cupsd conf The manual page for the CUPS printer daemon configuration file man classes conf The manual page for the class configuration file for CUPS 34 14 2 Useful Websites http www linuxprinting org GNU Linux Printing contains a large amount of information about printing in Linux http Awww cups org Documentation FAQs and newsgroups about CUPS Chapter 35 Automated Tasks In Linux tasks can be configured to run automatically within a specified period of time on a specified date or when the system load average is below a specified number Red Hat Enterprise Linux is pre configured 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 Enterprise Linux comes with several automated tasks utilities cron at and batch 35 1 Cron C
387. se Linux System Administration Guide is part of Red Hat s growing commitment to provide useful and timely support to Red Hat Enterprise Linux users As new tools and applications are released this guide will be expanded to include them Introduction vii 7 1 Send in Your Feedback If you find an error in the Red Hat Enterprise Linux System Administration 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 bugzilla redhat com bugzilla against the component rhel sag Be sure to mention the manual s identifier rhel sag EN 4 Print RHI 2005 06 06T17 10U1 By mentioning this manual s identifier we 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 when de scribing it If you have found an error please include the section number and some of the surrounding text so we can find it easily viii Introduction I Installation Related Information The Red Hat Enterprise Linux Installation Guide discusses the installation of Red Hat Enterprise Linux and some basic post installation troubleshooting However advanced installation options are covered in this manual This part provides instructions for kickstart an automated installation tech nique and all related tools Use this part in conjunction with the Red Hat Enterprise Linux Installation Guide to perform
388. se cron As root either use the crontab e command to schedule a periodic quotacheck or place a script that runs quotacheck in any one of the following directories using whichever interval best matches your needs e etc cron hourly e etc cron daily 102 Chapter 13 Implementing Disk Quotas e etc cron weekly e etc cron monthly The most accurate quota statistics can be obtained when the file system s analyzed are not in active use Thus the cron task should be schedule during a time where the file system s are used the least If this time is various for different file systems with quotas run quotacheck for each file system at different times with multiple cron tasks Refer to Chapter 35 Automated Tasks for more information about configuring cron 13 3 Additional Resources For more information on disk quotas refer to the following resources 13 3 1 Installed Documentation e The quotacheck edquota repquota quota quotaon and quotaoff man pages 13 3 2 Related Books e Red Hat Enterprise Linux Introduction to System Administration Red Hat Inc Available at http www redhat com docs and on the Documentation CD this manual contains background in formation on storage management including disk quotas for new Red Hat Enterprise Linux system administrators Chapter 14 Access Control Lists Files and directories have permission sets for the owner of the file the group associated with the file and all other
389. se this queue All hosts Network devices etho eth Network address Single IP address T Heip 2 Cancel OK Figure 34 18 Allowed Hosts The General tab configures settings for all printers including those not viewable with the Printer Configuration Tool There are two options Automatically find remote shared queues Selected by default this option enables IPP brows ing When other machines on the network broadcast the queues that they have the queues are automatically added to the list of printers available to the system no additional configuration is re quired for a printer found from IPP browsing This option does not automatically share the printers configured on the local system Enable LPD protocol This option allows the printer to receive print jobs from clients configured to use the LPD protocol using the cups 1pd service which is an xinetd service 274 Chapter 34 Printer Configuration A warming If this option is enabled all print jobs are accepted from all hosts if they are received from an LPD client Queue General These settings are system wide lt Automatically find remote shared queues Enable LPD protocol Help 3 Cancel 2 OK Figure 34 19 System wide Sharing Options 34 14 Additional Resources To learn more about printing on Red Hat Enterpri
390. sktop assumes that GNOME Desktop Environment and or KDE Desktop Environment has been installed through packages startxonboot Use a graphical login on the installed system resolution Specify the default resolution for the X Window System on the installed system Valid values are 640x480 800x600 1024x768 1152x864 1280x1024 1400x1050 1600x1200 Be sure to specify a resolution that is compatible with the video card and monitor depth Specify the default color depth for the X Window System on the installed system Valid values are 8 16 24 and 32 Be sure to specify a color depth that is compatible with the video card and monitor volgroup optional Use to create a Logical Volume Management LVM group with the syntax volgroup lt name gt lt partition gt lt options gt The options are as follows noformat Use an existing volume group and do not format it useexisting Use an existing volume group and reformat it Create the partition first create the logical volume group and then create the logical volume For example part pv 01 size 3000 volgroup myvg pv 01 logvol vgname myvg size 2000 name rootvol For a detailed example of volgroup in action refer to Section 1 4 1 Advanced Partitioning Example zerombr optional If zerombr is specified and yes is its sole argument any invalid partition tables found on disks are initialized This destroys all of the contents of disks
391. smb lt servername gt lt sharename gt 23 3 1 Command Line To query the network for Samba servers use the f indsmb command For each server found it displays its IP address NetBIOS name workgroup name operating system and SMB server version To connect to a Samba share from a shell prompt type the following command smbclient lt hostname gt lt sharename gt U lt username gt Replace lt hostname gt with the hostname or IP address of the Samba server you want to connect to lt sharename gt with the name of the shared directory you want to browse and lt username gt with the Samba username for the system Enter the correct password or press Enter if no password is required for the user If you see the smb gt prompt you have successfully logged in Once you are logged in type help for a list of commands If you wish to browse the contents of your home directory replace sharename with your username If the uU switch is not used the username of the current user is passed to the Samba server To exit smbclient type exit at the smb gt prompt 23 3 2 Mounting the Share Sometimes it is useful to mount a Samba share to a directory so that the files in the directory can be treated as if they are part of the local file system To mount a Samba share to a directory create the directory if it does not already exist and execute the following command as root mount t smbfs o username lt username gt lt s
392. sport Agent Switcher system switch mail nox see Mail Transport Agent Switcher T TCP wrappers 158 telinit 158 telnet 163 tftp 43 47 49 time configuration 235 synchronize with NTP server 236 time zone configuration 237 timetool see Time and Date Properties Tool token ring connection see network configuration top 301 tune2fs converting to ext3 with 60 reverting to ext2 with 61 U user configuration adding users 247 adding users to groups 249 additional information 254 changing full name 249 changing home directory 249 changing login shell 249 changing password 249 command line configuration 250 passwd 250 useradd 250 filtering list of users 247 locking user accounts 249 modify groups for a user 248 modifying users 248 password forcing expiration of 251 password expiration 249 setting user account expiration 249 viewing list of users 247 User Manager see user configuration useradd command user account creation using 250 users see user configuration V VeriSign using existing certificate 214 video card settings for dual head 244 settings for X 244 volume group 63 volume groups 70 331 W Windows file and print sharing 177 Windows 2000 connecting to shares using Samba 181 Windows 98 connecting to shares using Samba 181 Windows ME connecting to shares using Samba 181 Windows NT 4 0 connecting to shares using Samba 181 Windows XP connecting to s
393. ssed by RPM s freshen option it is upgraded to the newer version 116 Chapter 15 Package Management with RPM However RPM s freshen option does not install a package if no previously installed package of the same name exists This differs from RPM s upgrade option as an upgrade does install packages whether or not an older version of the package was already installed RPM s freshen option works for single packages or package groups If you have just downloaded a large number of different packages and you only want to upgrade those packages that are already installed on your system freshening does the job If you use freshening you do not have to delete any unwanted packages from the group that you downloaded before using RPM In this case issue the following command rpm Fvh rpm RPM automatically upgrades only those packages that are already installed 15 2 6 Querying Use the rpm q command to query the database of installed packages The rpm q foo command displays the package name version and release number of the installed package foo foo 2 0 1 f Note To query a package replace foo with the actual package name Instead of specifying the package name use the following options with q to specify the package s you want to query These are called Package Selection Options a queries all currently installed packages f lt file gt queries the package which owns lt file gt When specifying a f
394. stall Red Hat Enterprise Linux The BOOTP DHCP server provides 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 attempts an NFS mount of the file s path and copies 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 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 file name 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 file name the client searches for is lt ip addr gt kickstart The lt ip addr gt section of the file name should be replaced with the client s IP address in dotted decimal notation For example the file name for a computer with an IP address of 10 10 0 1 would be 10 10 0 1 kickstart Note that if you do not specify a server name then the client system attempts to use the server that answered the BOOTP DHCP request as its NFS server If you do not specify a path
395. stallation program stops at the monitor configuration screen To continue the installation process select your monitor from the list and click Next Alternatively you can select your monitor from the list You can also specify the horizontal and vertical sync rates instead of selecting a specific monitor by checking the Specify hysne and vsyne 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 2 9 Package Selection File Help Package Selection Select packages to install Basic Configuration Installation Method Boot Loader Options Automatically Resolve Dependencies Partition Information O Ignore Dependencies Desktops 2 Firewall Configuration X Window System Network Configuration Authentication Display Configuration Pre Installation Script Post Installation Script Package Selection GNOME Desktop Environment KDE K Desktop Environment Applications Editors Engineering and Scientific L Graphical Internet Text based Internet Office Productivity Sound and Video Graphics Games and Entertainment Authoring and Publishing Server Configuration Tools AS and ES only Web Server i Figure 2 14 Package Selection The Package Selection window allows you to choose
396. stalled for RPM verification execute the command rpm qa gpg pubkey For the Red Hat key the output includes gpg pubkey db42a60e 37ea5438 To display details about a specific key use rpm qi followed by the output from the previous com mand rpm qi gpg pubkey db42a60e 37ea5438 15 3 2 Verifying Signature of Packages To check the GnuPG signature of an RPM file after importing the builder s GnuPG key use the following command replace lt rom file gt with filename of the RPM package rpm K lt rpm file gt If all goes well the following message is displayed md5 gpg OK That means that the signature of the package has been verified and that it is not corrupt 15 4 Impressing Your Friends with RPM RPM is a useful tool for both managing your system and diagnosing and fixing problems The best way to make sense of all of its options is to look at some examples Perhaps you have deleted some files by accident but you are not sure what you deleted To verify your entire system and see what might be missing you could try the following command rpm Va If some files are missing or appear to have been corrupted you should probably either re install the package or uninstall and then re install the package Chapter 15 Package Management with RPM 119 At some point you might see a file that you do not recognize To find out which package owns it enter rpm qf usr bin ggv The output would look like the followin
397. sting kickstart file select File gt Open and select the existing file 2 1 Basic Configuration Eile Help Basic Configuration Basic Configuration required Installation Method Default Language English USA v Boon Laane Options Keyboard U S English v Partition Information PE Network Configuration Mouse Generic Wheel Mouse PS 2 M Authentication Emulate 3 Buttons Firewall Configuration Time Zone America New_York v Display Configuration E Package Selection O Use UTC clock Pre Installation Script Root Password Post4nstallation Script Confirm Password E Encrypt root password Language Support C1 Lao Laos Latvian Latvia Lithuanian a X Target Architecture x86 AMD64 or Intel EM64T W v Reboot system after installation Perform installation in text mode graphical is default Perform installation in interactive mode Figure 2 1 Basic Configuration Choose the language to use during the installation and as the default language to be used after instal lation from the Default Language menu Select the system keyboard type from the Keyboard menu Choose the mouse for the system from the Mouse menu If No Mouse is selected no mouse is configured If Probe for Mouse is selected the installation program tries to automatically detect the mouse Probing works for most modern mice If the system has a
398. strict this privilege to certain users by taking the following steps 1 Add the a option to the etc inittab line shown above so that it reads ca ctrlaltdel sbin shutdown a t3 r now The a flag tells shutdown to look for the etc shutdown allow file 2 Create a file named shutdown allow in etc The shutdown allow file should list the usernames of any users who are allowed to shutdown the system using Ctrl Alt Del The format of the shutdown allow file is a list of usernames one per line like the following stephen jack sophie According to this example shutdown allow file the users stephen jack and sophie are allowed to shutdown the system from the console using Ctrl Alt Del When that key combination is used the shutdown a command in etc inittab checks to see if any of the users in etc shutdown allow or root are logged in on a virtual console If one of them is the shutdown of the system continues if not an error message is written to the system console instead For more information on shutdown allow refer to the shutdown man page 232 Chapter 28 Console Access 28 2 Disabling Console Program Access To disable access by users to console programs run the following command as root rm f etc security console apps In environments where the console is otherwise secured BIOS and boot loader passwords are set Ctrl Alt Delete is disabled the power and reset switches are disabled and so fo
399. 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 file names In these cases they are considered to be part of the command so the entire phrase is displayed as a command For example Use the cat test ile command to view the contents of a file named test file in the current working directory Introduction iii file name File names directory names paths and RPM package names are represented this way This style indicates that a particular file or directory exists with that name on your system Examples The bashrc file in your home directory contains bash shell definitions and aliases for your own use The etc fstab file contains information about different system devices and file systems Install the webalizer RPM if you want to use a Web server log file analysis program application This style indicates that the program is an end user application as opposed to system software For example Use Mozilla to browse the Web key A key on the keyboard is shown in this style For example To use Tab completion t
400. swer gt where lt answer gt is one of the following 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 24 Dynamic Host Configuration Protocol DHCP 193 yes Modify etc resolv conf with information from the server If using DHCP then yes is the default no Do not modify etc resolv conf SRCADDR lt address gt where lt address gt is the specified source IP address for outgoing pack ets USERCTL lt answer gt where lt answer gt is one of the following yes Non root users are allowed to control this device no Non root users are not allowed to control this device If you prefer using a graphical interface refer to Chapter 18 Network Configuration for details on using the Network Administration Tool to configure a network interface to use DHCP o For advanced configurations of client DHCP options such as protocol timing lease requirements and requests dynamic DNS support aliases as well as a wide variety of values to override prepend or append to client side configurations refer to the dhclient and dhclient conf man pages 24 4 Additional Resources For configuration options not covered here refer to the following resources 24 4 1 Installed Documentation dhcpd man page Describes how the DHCP daemon works dhcpd conf man page Explains how to configure the DHCP configuration fi
401. t Configuration Protocol DHCP 191 The DHCP daemon could be killed or the system could crash after the lease database has been renamed to the backup file but before the new file has been written If this happens the dhcpd leases file does not exist but it is required to start the service Do not create a new lease file If you do all old leases are lost which causes many problems The correct solution is to rename the dhcpd leases backup file to dhcpd leases and then start the daemon 24 2 3 Starting and Stopping the Server Broren When the DHCP server is started for the first time it fails unless the dhcpd leases file exists Use the command touch var lib dhcp dhcpd leases to create the file if it does not exist If the same server is also running BIND as a DNS server this step is not necessary as starting the named service automatically checks for a dhcpd leases file To start the DHCP service use the command sbin service dhcpd start To stop the DHCP server use the command sbin service dhcpd stop By default the DHCP service does not start at boot time To configure the daemon to start auto matically at boot time refer to Chapter 20 Controlling Access to Services for information on how to manage services If more than one network interface is attached to the system but the DHCP server should only be started on one of the interfaces configure the DHCP server to start only on that device In etc sysconfig dhcpd add
402. t Specify group ID manually and select the GID Red Hat Enterprise Linux reserves group IDs lower than 500 for system groups Click OK to create the group The new group appears in the group list Group Name mygroup C Specify group ID manually GID 500 3 Cancel OK Figure 33 4 New Group To add users to the group refer to Section 33 4 Modifying Group Properties 250 Chapter 33 User and Group Configuration 33 4 Modifying Group Properties To view the properties of an existing group select the group from the group list and click Proper ties from the menu or choose File gt Properties from the pulldown menu A window similar to Figure 33 5 appears Group Data Group Users Group Name mygroup 3 Cancel 2 OK Figure 33 5 Group Properties The Group Users tab displays which users are members of the group Select additional users to be added to the group or unselect users to be removed from the group Click OK to modify the users in the group 33 5 Command Line Configuration If you prefer command line tools or do not have the X Window System installed use this section to configure users and groups 33 5 1 Adding a User To add a user to the system 1 Issue the useradd command to create a locked user account useradd lt username gt 2 Unlock the account by issuing the passwd command to assign a password and set password agin
403. t for the rlogin rsh and telnet commands It allows you to log in to a remote machine as well as execute commands on a remote machine Logging in to a remote machine with ssh is similar to using telnet To log in to a remote machine named penguin example net type the following command at a shell prompt ssh penguin example net The first time you ssh to a remote machine you will see a message similar to the following The authenticity of host penguin example net can t be established DSA key fingerprint is 94 68 3a 3a bc 3 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 ssh 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 exam
404. t password security level time zone and networking configuration options in addition to the default ones 2 8 2 Video Card Probe for video card is selected by default Accept this default to have the installation program probe for the video card during installation Probing works for most modern video cards If this option is selected and the installation program cannot successfully probe the video card the installation program stops at the video card configuration screen To continue the installation process select your video card from the list and click Next Alternatively you can select the video card from the list on the Video Card tab as shown in Figure 2 12 Specify the amount of video RAM the selected video card has from the Video Card RAM pulldown menu These values are used by the installation program to configure the X Window System 38 Chapter 2 Kickstart Configurator File Help Basic Configuration Display Configuration Installation Method Configure the X Window System Boot Loader Options General Video Card Monitor Partition Information Pioba foi videa card Network Configuration aa Authentication Matrox Comet Firewall Configuration Matrox Marvel II Display Configuration Matrox Millennium Package Selection Matrox Millennium G200 Pre Installation Script Post Installation Script Matrox Millennium G450 Matrox Millennium G550 Matrox Millennium II Matrox Mystique
405. t the runlevel is not restarted thus the changes do not take place immediately For example assume you are configuring runlevel 3 If you change the value for the httpd service from checked to unchecked and then select Save Changes the runlevel 3 configuration changes so that httpd is not started at boot time However runlevel 3 is not reinitialized so httpd is still running Select one of following options at this point 1 Stop the httpd service Stop the service by selecting it from the list and clicking the Stop button A message appears stating that the service was stopped successfully 2 Reinitialize the runlevel Reinitialize the runlevel by going to a shell prompt and typing the command telinit 3 where 3 is the runlevel number This option is recommended if you change the Start at Boot value of multiple services and want to activate the changes immedi ately 3 Do nothing else You do not have to stop the httpd service You can wait until the system is rebooted for the service to stop The next time the system is booted the runlevel is initialized without the httpd service running To add a service to a runlevel select the runlevel from the Edit Runlevel pulldown menu and then select Actions gt Add Service To delete a service from a runlevel select the runlevel from the Edit Runlevel pulldown menu select the service to be deleted from the list on the left and select Actions gt Delete Service 20 4 ntsysv
406. tails Installing packages is designed to be simple but you may sometimes see errors 15 2 2 1 Package Already Installed If the package of the same version is already installed the following is displayed Preparing SEA AEA AE AE ARE AE AE AE HE A AE AE AEA EE EEA EERE EAE 100 package foo 1 0 1 is already installed If the same version you are trying to install is already installed and you ewant to install the package anyway you can use the replacepkgs option which tells RPM to ignore the error rpm ivh replacepkgs foo 1 0 1 1386 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 15 2 2 2 Conflicting Files If you attempt to install a package that contains a file which has already been installed by another package or an earlier version of the same package the following is displayed Preparing SEA AE AAR EAE AE ARATE FE AR AEE AE AE AE EEE EEA EERE EERE 100 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 114 Chapter 15 Package Management with RPM 15 2 2 3 Unresolved Dependency RPM packages can essentially depend on other packages which means that they require other pack ages to be installed to run properly If you try to install a package which has an unreso
407. tails xconfig optional Configures the X Window System If this option is not given the user must configure X manually during the installation if X was installed this option should not be used if X is not installed on the final system noprobe Do not probe the monitor card Use specified card this card name should be from the list of cards in usr share hwdata Cards from the hwdata package The list of cards can also be found on the X Configuration screen of the Kickstart Configurator If this argument is not provided the installation program probes the PCI bus for the card Since AGP is part of the PCI bus AGP cards are detected if supported The probe order is determined by the PCI scan order of the motherboard videoram Specifies the amount of video RAM the video card has monitor Use specified monitor monitor name should be from the list of monitors in usr share hwdata MonitorsDB from the hwdata package The list of monitors can also be found on the X Configuration screen of the Kickstart Configurator This is ignored if hsync or vsync is provided If no monitor information is provided the installation program tries to probe for it automatically hsync Specifies the horizontal sync frequency of the monitor vsync Specifies the vertical sync frequency of the monitor Chapter 1 Kickstart Installations 17 defaultdesktop Specify either GNOME or KDE to set the default de
408. tands for the Universal Time Coordinated also known as Greenwich mean time GMT Other time zones are determined by adding or subtracting from the UTC time 238 Chapter 29 Date and Time Configuration Chapter 30 Keyboard Configuration The installation program allows users to configure a keyboard layout for their systems To configure a different keyboard layout after installation use the Keyboard Configuration Tool To start the Keyboard Configuration Tool select Applications the main menu on the panel gt System Settings gt Keyboard or type the command system config keyboard at a shell prompt SS Select the appropriate keyboard for the system SpeaKup Wapropy Swedish Swiss French Swiss French latin1 Swiss German Swiss German latin1 Turkish Ukrainian United Kingdom U S International oS OK Figure 30 1 Keyboard Configuration Tool Select a keyboard layout from the list for example U S English and click OK For changes to take effect you should log out of your graphical desktop session and log back in 240 Chapter 30 Keyboard Configuration Chapter 31 Mouse Configuration The installation program allows users to select the type of mouse connected to the system To configure a different mouse type for the system use the Mouse Configuration Tool To start the Mouse Configuration Tool type the command system config mouse at a shell prompt for
409. ter 6 The ext3 File System 61 6 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 mapper VolGroup00 LogVol02 Next change the file system type to ext2 by typing the following command as root sbin tune2fs O has_journal dev mapper VolGroup00 LogVol02 Check the partition for errors by typing the following command as root sbin e2fsck y dev mapper VolGroup00 LogVol02 Then mount the partition again as ext2 file system by typing mount t ext2 dev mapper VolGroup00 LogVol02 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 want to permanently change the partition to ext2 remember to update the etc fstab file 62 Chapter 6 The ext3 File System Chapter 7 Logical Volume Manager LVM 7 1 What is LVM LVM is a method of allocating hard drive space into logical volumes that can be easily resized instead of partitions With LVM a hard drive or set
410. ter Configuration 259 Queue name Please enter a name for this queue Choose a short name that begins with a letter and contains no spaces Name printer About If you like you can enter a description of the printer to help you identify it more easily Short description T Heip 3 Cancel lt d Back Figure 34 3 Selecting a Queue Name After clicking Forward Figure 34 4 appears Select Locally connected from the Select a queue type menu and select the device The device is usually dev 1p0 for a parallel printer or dev usb 1p0 for a USB printer If no devices appear in the list click Rescan devices to rescan the computer or click Custom device to specify it manually Click Forward to continue Select a queue type Locally connected z dev ip0 Rescan devices custom device T Heip Cancel lt d Back Figure 34 4 Adding a Local Printer Next select the printer type Refer to Section 34 7 Selecting the Printer Model and Finishing for de tails 34 2 Adding an IPP Printer An IPP printer is a printer attached to a different Linux system on the same network running CUPS or a printer configured on another operating system to use IPP By default the Printer Configuration Tool browses the network for any shared IPP printers This option can be changed by selecting Action gt Sharing from the pulldown menu
411. ter boots to runlevel 1 Your local file systems are mounted but your network is not activated You have a usable system maintenance shell Unlike rescue mode single user mode automatically tries to mount your file system Do not use single user mode if your file system cannot be mounted successfully You cannot use single user mode if the runlevel configuration on your system is corrupted On an x86 system using GRUB use the following steps to boot into single user mode 1 At the GRUB splash screen at boot time press any key to enter the GRUB interactive menu 2 Select Red Hat Enterprise Linux with the version of the kernel that you wish to boot and type a to append the line 3 Go to the end of the line and type single as a separate word press the Spacebar and then type single Press Enter to exit edit mode 5 4 Booting into Emergency Mode In emergency mode you are booted into the most minimal environment possible The root file system is mounted read only and almost nothing is set up The main advantage of emergency mode over single user mode is that the init files are not loaded If init is corrupted or not working you can still mount file systems to recover data that could be lost during a re installation To boot into emergency mode use the same method as described for single user mode in Section 5 3 Booting into Single User Mode with one exception replace the keyword single with the keyword emergency ll File Syste
412. tes Schedule delivery of Errata Updates Package installation Schedule package installation on one or more systems with the click of a button Red Hat Update Agent Use the Red Hat Update Agent to download the latest software pack ages for your system with optional package installation Red Hat Network website Manage multiple systems downloaded individual packages and schedule actions such as Errata Updates through a secure Web browser connection from any com puter QO caution You must activate your Red Hat Enterprise Linux product before registered your system with Red Hat Network to make sure your system is entitled to the correct services To activate your product go to http www redhat com apps activate After activating your product register it with Red Hat Network to receive Errata Updates The reg istration process gathers information about the system that is required to notify you of updates For example a list of packages installed on the system is compiled so you are only notified about updates that are relevant to your system The first time the system is booted the Setup Agent prompts you to register If you did not register then select Applications the main menu on the panel gt System Tools gt Red Hat Network on your desktop to start the registration process Alternately execute the command up2date from a shell prompt Chapter 17 Red Hat Network to this system Include RPM pac
413. th static IP information including a nameserver you can access the network and resolve IP addresses in the post section If you configured the network for DHCP the etc resolv conf file has not been completed when the installation executes the 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 post section Note The post install script is run in a chroot environment therefore performing tasks such as copying scripts or RPMs from the installation media do not work nochroot Allows you to specify commands that you would like to run outside of the chroot environment The following example copies the file etc resolv conf to the file system that was just in stalled Spost nochroot cp etc resolv conf mnt sysimage etc resolv conf 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 1 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 22 Chapter 1 Kickstart Installations Run a script named runme from an NFS share mkdir mnt temp mount o nolock 10 10 0 2 usr new machines mnt temp open s w mnt temp runme umount mnt temp f Note NFS file locking is not s
414. the executable with the smallest number of samples to the one with the largest number of samples 314 Chapter 41 OProfile 41 5 2 Using opreport on a Single Executable To retrieve more detailed profiled information about a specific executable use opreport opreport lt mode gt lt executable gt lt executable gt must be the full path to the executable to be analyzed lt mode gt must be one of the following Sal List sample data by symbols For example the following is part of the output from running the command opreport 1 lib tls libc lt version gt so samples symbol name 12 21 4286 gconv_transform_utf8_internal 9286 _int_malloc 1429 malloc 3571 __i1686 get_pc_thunk bx 85 1 dl_mcount_wrapper_check 3571 mbrtowc 3571 memcpy 5714 _int_realloc 5714 _nl_intern_locale_data oO 5714 free 5714 strcmp 27857 ctype_get_mb_cur_max 7857 __unregister_atfork 7857 __write_nocancel 7857 _dl_addr 7857 _int_free 7857 _itoa_word 7857 calc_eclosure_iter 7857 fopen GLIBC_2 1 7857 getpid 7857 memmove 7857 msort_with_tmp 7857 strcpy 7857 strlen 7857 VED INCE 7857 write PRPPPRPRPRPRPRPRPRPRPRPEFRENNNNWWWWA PRPPPRPPRPEPREPEPREPRPRPWWWWONUuUHnArIarF The first column is the starting virtual memory address vma The second column is the number of samples for the symbol The third column is the percentage of samples for this symbol relative to the overall samples for the execut
415. the same name as a user is called a user private group For more information on user private groups refer to Section 33 1 Adding a New User The line created in etc group has the following characteristics It begins with the group name juan An x appears in the password field indicating that the system is using shadow group pass words The GID matches the one listed for user juan in etc passwd 4 A new line for a group named juan is created in etc gshadow The line has the following characteristics It begins with the group name juan An exclamation point appears in the password field of the etc gshadow file which locks the group All other fields are blank 5 A directory for user juan is created in the home directory This directory is owned by user juan and group juan However it has read write and execute privileges only for the user juan All other permissions are denied 6 The files within the etc ske1l directory which contain default user settings are copied into the new home juan directory At this point a locked account called juan exists on the system To activate it the administrator must next assign a password to the account using the passwd command and optionally set password aging guidelines 33 7 Additional Information Refer to these resources for more information on user and group management Chapter 33 User and Group Configuration 255 33 7 1 Installed Documentation
416. ting commands to ensure that it is executed last A good priority number for ssh add is 70 or higher The higher the priority number the lower the priority If you have other programs listed this one should have the lowest priority Click Close to exit the program 3 Log out and then log back into GNOME in other words 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 168 Chapter 21 OpenSSH 21 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 refer to Section 21 3 4 4 Configuring ssh agent with GNOME this procedure will work in a terminal window such as an XTerm If you are running X but not GNOME this procedure will work in a terminal window However your passphrase will only be remembered for that terminal window it is not a global setting 1 At a shell prompt type the following command exec usr bin ssh agent SHELL 2 Then type the command ssh add and enter your passphrase s If y
417. tion program sets up the dynamic loading mechanism to work transparently If new hardware is added after installation and the hardware requires a kernel module the system must be configured to load the proper kernel module for the new hardware When the system is booted with the new hardware the Kudzu program runs detects the new hardware if it is supported and configures the module for it The module can also be specified manually by editing the module configuration file etc modprobe conf f Note Video card modules used to display the X Window System interface are part of the xorg x11 pack ages not the kernel thus this chapter does not apply to them For example if a system included an SMC EtherPower 10 PCI network adapter the module configu ration file contains the following line alias eth0 tulip If a second network card is added to the system and is identical to the first card add the following line to etc modules conf alias ethl tulip Refer to the Red Hat Enterprise Linux Reference Guide for an alphabetical list of kernel modules and supported hardware for those modules 38 1 Kernel Module Utilities A group of commands for managing kernel modules is available if the module init tools package is installed Use these commands to determine if a module has been loaded successfully or when trying different modules for a piece of new hardware The command sbin 1smod displays a list of currently loaded modules For
418. to determine the processor load over a given period of time This data can then be used to determine if additional processors or a faster processor might improve system performance 41 8 Graphical Interface Some OProfile preferences can be set with a graphical interface To start it execute the oprof_start command as root at a shell prompt After changing any of the options save them by clicking the Save and quit button The preferences are written to root oprofile daemonrc and the application exits Exiting the application does not stop OProfile from sampling On the Setup tab to set events for the processor counters as discussed in Section 41 2 2 Setting Events to Monitor select the counter from the pulldown menu and select the event from the list A brief description of the event appears in the text box below the list Only events available for the specific counter and the specific architecture are displayed The interface also displays whether the profiler is running and some brief statistics about it Chapter 41 OProfile 317 Setup Configuration Counter 0 BUS_DRDY_CLOCKS S Counter settings 7 Enabled gt K Event Profile kermel L2_DBUS_BUSY L2_DBUS_BUSY_RD E Profile user binaries BUS_DRDY_CLOCKS Count 397952 BUS_LOCK_CLOCKS Unit mask BUS_REQ_OUTSTANDING BUS_TRAN_BRD BUS_TRAN_RFO BUS_TRANS_WB BUS_TRAN_IFETCH BUS_TRAN_INVAL BUS_TRAN_PWR BUS
419. to implement refer to Chapter 9 Redundant Array of Independent Disks RAID Note If you are making a RAID partition of boot you must choose RAID level 1 and it must use one of the first two drives IDE first SCSI second If you are not creating a seperate RAID partition of boot and you are making a RAID partition for the root file system it must be RAID level 1 and must use one of the first two drives IDE first SCSI second Error With Request Bootable partitions can only be on RAID1 devices 2 OK Figure 10 7 The boot Mount Error 8 The RAID partitions created appear in the RAID Members list Select which of these partitions should be used to create the RAID device 9 If configuring RAID 1 or RAID 5 specify the number of spare partitions If a software RAID partition fails the spare is automatically 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 Select the partitions for the RAID device and the partition s for the spare s 82 Chapter 10 Software RAID Configuration 10 After clicking OK the RAID device appears in the Drive Summary list 11 Repeat this chapter s entire process for configuring additional partitions devices and mount points such as the root partition home or swap After completing the entire configuration the figure as shown in Figure 10
420. to return to the webpage you last viewed computer output Text in this style indicates text displayed to a shell prompt such as error messages and responses to commands For example The 1s command displays the contents of a directory For example iv Introduction Desktop about html logs paulwesterberg png Mail backupfiles mail reports The output returned in response to the command in this case the contents of the directory is shown in this style prompt A prompt which is a computer s way of signifying that it is ready for you to input something is shown in this style Examples stephen maturin stephen leopard login user input Text that the user types either on the command line or into a text box on a GUI screen is displayed in this style In the following example text is displayed in this style To boot your system into the text based installation program you must type in the text com mand at the boot prompt lt replaceable gt Text used in examples that is meant to be replaced with data provided by the user is displayed in this style In the following example lt version number gt is displayed in this style The directory for the kernel source is usr src kernels lt version number gt where lt version number gt is the version and type of kernel installed on this system Additionally we use several different strategies to draw your attention to certain pieces of information In order of
421. to the number of samples for the symbol is displayed x lt symbol name gt Exclude the comma separated list of symbols from the output session lt name gt Specify the full path to the session or a directory relative to the var lib oprofile samples directory 41 5 3 Using opannotate The opannotate tool tries to match the samples for particular instructions to the corresponding lines in the source code The resulting files generated should have the samples for the lines at the left It also puts in a comment at the beginning of each function listing the total samples for the function For this utility to work the executable must be compiled with GCC s g option By default Red Hat Enterprise Linux packages are not compiled with this option The general syntax for opannotate is as follows opannotate search dirs lt src dir gt source lt executable gt The directory containing the source code and the executable to be analyzed must be specified Refer to the opannotate man page for a list of additional command line options 41 6 Understanding dev oprofile The dev oprofile directory contains the file system for OProfile Use the cat command to display the values of the virtual files in this file system For example the following command displays the type of processor OProfile detected cat dev oprofile cpu_type A directory exists in dev oprofile for each counter For example if there are 2 counters the direc
422. tories dev oprofile 0 and dev oprofile 1 exist 316 Chapter 41 OProfile Each directory for a counter contains the following files count The interval between samples enabled If 0 the counter is off and no samples are collected for it if 1 the counter is on and samples are being collected for it event The event to monitor kernel If 0 samples are not collected for this counter event when the processor is in kernel space if 1 samples are collected even if the processor is in kernel space e unit_mask Defines which unit masks are enabled for the counter user If 0 samples are not collected for the counter event when the processor is in user space if 1 samples are collected even if the processor is in user space The values of these files can be retrieved with the cat command For example cat dev oprofile 0 count 41 7 Example Usage While OProfile can be used by developers to analyze application performance it can also be used by system administrators to perform system analysis For example Determine which applications and services are used the most on a system opreport can be used to determine how much processor time an application or service uses If the system is used for multiple services but is under performing the services consuming the most processor time can be moved to dedicated systems Determine processor usage The CPU_CLK_UNHALTED event can be monitored
423. tter PostScript test page Queue nam amp A4 PostScript test page ASCII text test page Japanese EUC text test page amp Japanese JIS text test page Q Japanese SJIS text test page amp Japanese EUC PostScript test page Japanese JIS PostScript test page amp Japanese SJIS PostScript test page amp Duplex test JPEG test Figure 34 11 Test Page Options 34 9 Modifying Existing Printers To delete an existing printer select the printer and click the Delete button on the toolbar The printer is removed from the printer list Click Apply to save the changes and restart the printer daemon To set the default printer select the printer from the printer list and click the Default button on the toolbar The default printer icon y appears in the Default column of the default printer in the list A IPP browsed queue printer can not be set as the default printer in the Printer Configuration Tool To make an IPP printer the default add it as described in Section 34 2 Adding an IPP Printer and make it the default Note The GNOME Print Manager no longer sets user level default printers In order to set a default printer system wide use the system config printer command or the Printer Configuration Tool In order for users to configure a default printer for themselves only each user should use the GNOME Default Printer Tool which can be found by selecting Applications on the Panel gt Preferences gt More Preference
424. tures of ext3 eis 6 2 Creating an ext3 File System 6 3 Converting to an ext3 File System 6 4 Reverting to an ext2 File System a T Logical Volume Manager VM scsi casecstsviescvscseusvaseseetes iniii 63 Te What is CVM oraora ri E aes cases tty sear cay ese EEE N A AEA 63 7 2 What is LVM2 es T3 Additional Resources cssssssecesssessgsssts dvacssssyetesteeseisaneessestueseatanuyeiaavendssagiassastaeass s SEVM Config ratioi errer a e ETE AE EREE E E TAAS 8 1 Automatic Partitioning 8 2 Manual LVM Partitioning 9 Redundant Array of Independent Disks RAID 9 1 What is RAID owen 9 2 Who Should Use RAID ee 9 3 Hardware RAID versus Software RAID 9 4 RAID Levels and Linear Support 10 Software RAID Configuration 10 1 Creating the RAID Partitions 10 2 Creating the RAID Devices and Mount Points 0 0 eee eeeeeeteeeeeeeeeneee 80 11 Swap Space s 11 0 What is Swap Space nenir eiia i i e R E ORE AR 85 11 2 Addi g Swap Spacenrarmeniie iin a a an a ivi 85 11 3 Removing Swap Space 11 4 Moving Swap Space 12 Managing Disk Storage ee 89 12 1 Standard Partitions using parted 89 12 2 LVM Partition Management 1 94 13 Implementing Disk Quotas i e oiiire iniri ie iE e EAE EEEE 97 13 1 Configuring Disk Quotas neres proti er i EERE EERE 97 13 2 Managing Disk Quotas 13 3 Additonal
425. two button mouse a three button mouse can be emulated by selecting Emulate 3 Buttons If this option is selected simultaneously clicking the left and right mouse buttons are recognized as a middle mouse button click 28 Chapter 2 Kickstart Configurator From the Time Zone menu choose the time zone to use for the system To configure the system to use UTC select Use UTC clock Enter the desired root password for the system in the Root Password text entry box Type the same password in the Confirm Password text box The second field is to make sure you do not mistype the password and then realize you do not know what it is after you have completed the installation To save the password as an encrypted password in the file select Encrypt root password If the encryp tion option is selected when the file is saved the plain text password that you typed are encrypted and written to the kickstart file Do not type an already encrypted password and select to encrypt it Because a kickstart file is a plain text file that can be easily read it is recommended that an encrypted password be used To install languages in addition to the one selected from the Default Language pulldown menu check them in the Language Support list The language selected from the Default Language pulldown menu is used by default after installation however the default can be changed with the Language Configuration Tool system conf ig language after installation Choos
426. u etc grub conf Similarly removing an old unneeded kernel removes the kernel from GRUB Because RPM performs intelligent upgrading of packages with configuration files you may see a message like the following saving etc foo conf as etc foo conf rpmsave This message means that your changes to the configuration file may not be forward compatible with the new configuration file in the package so RPM saved your original file and installed a new one You should investigate the differences between the two configuration files and resolve them as soon as possible to ensure that your system continues to function properly Upgrading is really a combination of uninstalling and installing so during an RPM upgrade you can encounter uninstalling and installing errors plus one more If RPM thinks you are trying to upgrade to a package with an older version number the output is similar to the following package foo 2 0 1 which is newer than foo 1 0 1 is already installed To force RPM to upgrade anyway use the oldpackage option rpm Uvh oldpackage foo 1 0 1 i386 rpm 15 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 RPMs 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 proce
427. uage langsupport default en_US fr_FR If you use default with only one language all languages are installed with the specified language set to the default 10 Chapter 1 Kickstart Installations logvol optional Create a logical volume for Logical Volume Management LVM with the syntax logvol lt mntpoint gt vgname lt name gt size lt size gt name lt name gt lt options gt The options are as follows noformat Use an existing logical volume and do not format it useexisting Use an existing logical volume and reformat it Create the partition first create the logical volume group and then create the logical volume For example part pv 01 size 3000 volgroup myvg pv 01 logvol vgname myvg size 2000 name rootvol For a detailed example of logvol in action refer to Section 1 4 1 Advanced Partitioning Example mouse required Configures the mouse for the system both in GUI and text modes Options are device Device the mouse is on such as device ttyS0 emulthree If present simultaneous clicks on the left and right mouse buttons are recognized as the middle mouse button by the X Window System This option should be used if you have a two button mouse After options the mouse type may be specified as one of the following alpsps 2 ascii asciips 2 atibm generic generic3 genericps 2 generic3ps 2 genericwheelps 2 genericusb generic3usb genericwheelusb ge
428. ual disk Lessened impact of a disk failure 9 3 Hardware RAID versus Software RAID There are two possible RAID approaches Hardware RAID and Software RAID 9 3 1 Hardware RAID The hardware based array manages the RAID subsystem independently from the host and presents to the host only a single disk per RAID array An example of a Hardware RAID device would be one that connects to a SCSI controller and presents the RAID arrays as a single SCSI drive An external RAID system moves all RAID handling intelli gence into a controller located in the external disk subsystem The whole subsystem is connected to the host via a normal SCSI controller and appears to the host as a single disk RAID controllers also come in the form of cards that act like a SCSI controller to the operating system but handle all of the actual drive communications themselves In these cases you plug the drives into the RAID controller just like you would a SCSI controller but then you add them to the RAID controller s configuration and the operating system never knows the difference 74 Chapter 9 Redundant Array of Independent Disks RAID 9 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
429. ue type is chosen different options are displayed Refer to the appropriate section on adding a printer for a description of the options 34 9 3 Printer Driver The Printer driver tab shows which print driver is currently being used If it is changed click OK to return to the main window Click Apply to save the change and restart the printer daemon 34 9 4 Driver Options The Driver options tab displays advanced printer options Options vary for each print driver Common options include Prerender Postscript should be selected if characters beyond the basic ASCH set are being sent to the printer but they are not printing correctly such as Japanese characters This option prerenders non standard PostScript fonts so that they are printed correctly If the printer does not support the fonts you are trying to print try selecting this option For example select this option to print Japanese fonts to a non Japanese printer Extra time is required to perform this action Do not choose it unless problems printing the correct fonts exist 268 Chapter 34 Printer Configuration Also select this option if the printer can not handle PostScript level 3 This option converts it to PostScript level 1 GhostScript pre filtering allows you to select No pre filtering Convert to PS level 1 or Convert to PS level 2 in case the printer cannot handle certain PostScript levels This option is only available if the PostScript driver is used
430. up on the system m lt perms gt Sets the effective rights mask The mask is the union of all permissions of the owning group and all of the user and group entries o lt perms gt Sets the access ACL for users other than the ones in the group for the file White space is ignored Permissions lt perms gt must be a combination of the characters r w and x for read write and execute If a file or directory already has an ACL and the set facl command is used the additional rules are added to the existing ACL or the existing rule is modified For example to give read and write permissions to user andrius setfacl m u andrius rw project somefile To remove all the permissions for a user group or others use the x option and do not specify any permissions setfacl x lt rules gt lt files gt For example to remove all permissions from the user with UID 500 setfacl x u 500 project somefile Chapter 14 Access Control Lists 105 14 3 Setting Default ACLs To set a default ACL add d before the rule and specify a directory instead of a file name For example to set the default ACL for the share directory to read and execute for users not in the user group an access ACL for an individual file can override it setfacl m d o rx share 14 4 Retrieving ACLs To determine the existing ACLs for a file or directory use the get facl command getfacl lt filename gt It returns output similar to the following
431. upported while in kickstart mode therefore o nolock is required when mounting an NFS mount Add a user to the system usr sbin useradd bob usr bin chfn f Bob Smith bob usr sbin usermod p kjdf 04930FTH bob 1 8 Making the Kickstart File Available A kickstart file must be placed in one of the following locations Ona boot diskette Ona boot CD ROM Ona network Normally a kickstart file is copied to the boot diskette or made available on the network The network based approach is most commonly used as most kickstart installations tend to be performed on net worked computers Let us take a more in depth look at where the kickstart file may be placed 1 8 1 Creating Kickstart Boot Media Diskette based booting is no longer supported in Red Hat Enterprise Linux Installations must use CD ROM or flash memory products for booting However the kickstart file may still reside on a diskette s top level directory and must be named ks cfg To perform a CD ROM based kickstart installation the kickstart file must be named ks cfg and must be located in the boot CD ROM s top level directory Since a CD ROM is read only the file must be added to the directory used to create the image that is written to the CD ROM Refer to the Red Hat Enterprise Linux Installation Guide for instructions on creating boot media however before making the file iso image file copy the ks cfg kickstart file to the isolinux directory
432. ur partitions do not have to be RAID partitions After creating all the partitions needed to form a RAID device follow these steps 1 Click the RAID button 2 Select Create a RAID device 3 Select a mount point file system type RAID device name RAID level RAID members number of spares for the software RAID device and whether to format the RAID device Mount Point home _ x File System Type ext3 z RAID Device mdo z RAID Level 0 Y E raid o1 Raid Members raid 02 Number of spares 1 7 Format RAID device X Cancel Pox Figure 2 7 Creating a Software RAID Device 4 Click OK to add the device to the list 34 Chapter 2 Kickstart Configurator 2 5 Network Configuration File Help Basic Configuration Network Configuration Installation Method Device Network Type Add Network Device Boot Loader Options Edit N Partition Information Network Configuration Authentication Firewall Configuration Display Configuration Package Selection Pre Installation Script Post4nstallation Script Figure 2 8 Network Configuration If the system to be installed via kickstart does not have an Ethernet card do not configure one on the Network Configuration page Networking is only required if you choose a networking based installation method NFS FTP or HTTP Networking can always be configured after
433. ure which services are started at boot time for each runlevel Non xinetd services can not be started stopped or restarted using this program e chkconfig a command line utility that allows you to turn services on and off for the different runlevels Non xinetd services can not be started stopped or restarted using this utility You may find that these tools are easier to use than the alternatives editing the numerous symbolic links located in the directories below etc rc d by hand or editing the xinetd configuration files in etc xinetd d Another way to manage access to system services is by using iptables to configure an IP firewall If you are a new Linux user please realize that iptables may not be the best solution for you Setting up iptables can be complicated and is best tackled by experienced Linux system administrators On the other hand the benefit of using iptables is flexibility For example if you need a customized solution which provides certain hosts access to certain services iptables can provide it for you Refer to the Red Hat Enterprise Linux Reference Guide and the Red Hat Enterprise Linux Security Guide for more information about iptables Alternatively if you are looking for a utility to set general access rules for your home machine and or if you are new to Linux try the Security Level Configuration Tool system config securitylevel which allows you to select the security level for your system similar
434. ured to use the correct kernel module for the card If a card is added after installation Kudzu should recognize it and prompt for the configuration of the corresponding kernel module for it Be sure to check the Hardware Compatibility List available at http hardware redhat com hcl If the network card is not configured by the installation program or Kudzu and you know which kernel module to load for it refer to Chapter 38 Kernel Modules for details on loading kernel modules To configure a DHCP client manually 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 The NETWORKING variable must be set to yes if you want networking to start at boot time The etc sysconfig network scripts ifcfg eth0 file should contain the following lines DEVICE eth0 BOOTPROTO dhcp ONBOOT yes A configuration file is needed for each device to be configured to use DHCP Other options for the network script include DHCP_HOSTNAME Only use this option if the DHCP server requires the client to specify a host name before receiving an IP address The DHCP server daemon in Red Hat Enterprise Linux does not support this feature PEERDNS lt an
435. urgency these items are marked as a note tip important caution or warning For example Note Remember that Linux is case sensitive In other words a rose is not a ROSE is not a rOsE Ori The directory usr share doc contains additional documentation for packages installed on your system noran If you modify the DHCP configuration file the changes do not take effect until you restart the DHCP daemon Introduction v O caution Do not perform routine tasks as root use a regular user account unless you need to use the root account for system administration tasks A waming Be careful to remove only the necessary partitions Removing other partitions could result in data loss or a corrupted system environment 4 Activate Your Subscription Before you can access service and software maintenance information and the support documenta tion included in your subscription you must activate your subscription by registering with Red Hat Registration includes these simple steps Provide a Red Hat login Provide a subscription number Connect your system The first time you boot your installation of Red Hat Enterprise Linux you are prompted to register with Red Hat using the Setup Agent If you follow the prompts during the Setup Agent you can complete the registration steps and activate your subscription If you can not complete registration during the Setup Agent which requires network access you can alte
436. users smbidmapgid lt lowest highest gt GID range winbind assigns to domain or ADS users winbindseparator lt gt Character used to separate the domain and user part of winbind usernames if winbindusedefaultdomain is not enabled winbindtemplatehomedir lt home D U gt Directory that winbind users have as their home winbindtemplateprimarygroup lt nobody gt Group that winbind users have as their primary group winbindtemplateshell lt bin false gt Shell that winbind users have as their default login shell enablewinbindusedefaultdomain Configures winbind to assume that users with no domain in their usernames are domain users 228 Chapter 27 Authentication Configuration Option Description O disablewinbindusedefaultdomain Configures winbind to assume that users with no domain in their usernames are not domain users winbindjoin lt Administrator gt Joins the winbind domain or ADS realm now as this administrator disablewins Disable WINS for hostname resolution nostart Do not start or stop the portmap ypbind or nscd services even if they are configured Do not display the user interface Probe and display network defaults Table 27 1 Command Line Options V System Configuration Part of a system administrator s job is configuring the system for various tasks types of users and hardware configurations This section explains how to configure a Red Hat Enterprise Linux system
437. v sound dev beep dev snd lt cdrom gt dev cdrom dev cdroms dev cdwriter mnt cdrom You can add your own lines to this section if necessary Make sure that any lines you add refer to the appropriate device For example you could add the following line lt scanner gt dev scanner dev usb scanner Of course make sure that dev scanner is really your scanner and not say your hard drive That is the first step The second step is to define what is done with those files Look in the last section of etc security console perms for lines similar to Chapter 28 Console Access 233 lt console gt 0660 lt floppy gt 0660 root floppy lt console gt 0600 lt sound gt 0640 root lt console gt 0600 lt cdrom gt 0600 root disk and add a line like lt console gt 0600 lt scanner gt 0600 root Then when you log in at the console you are given ownership of the dev scanner device with the permissions of 0600 readable and writable by you only When you log out the device is owned by root and still has the permissions 0600 now readable and writable by root only 28 5 Enabling Console Access for Other Applications To make other applications accessible to console users a bit more work is required First of all console access only works for applications which reside in sbin or usr sbin so the application that you wish to run must be there After verifying that do the following steps 1 Create a link fr
438. vailable keyboards on i386 Itanium and Alpha machines be latinl bg br abnt2 cf cz lat2 cz us qwertz de de latinl de latinl nodeadkeys dk dk latinl dvorak es et fi fi latinl fr fr latinO fr latinl fr pc fr_CH fr_CH latinl gr hu hul01 is latinl it it ibm it2 jp106 la latinl mk utf no no latinl pl pt latinl ro_win ru ru cpl251 ru ms rul ru2 ru_win se latinl sg sg latinl sk qwerty slovene speakup speakup lt sv latinl sg sg latinl sk querty slovene trq ua uk us us acentos The file usr lib python2 2 site packages rhpl keyboard_models py also contains this list and is part of the rhp1 package lang required Sets the language to use during installation For example to set the language to English the kickstart file should contain the following line lang en_US The file usr share system config language locale list provides a list of the valid language codes in the first column of each line and is part of the system config language package langsupport required Sets the language s to install on the system The same language codes used with lang can be used with Langsupport To install one language specify it For example to install and use the French language fr_FR langsupport fr_FR default If language support for more than one language is specified a default must be identified For example to install English and French and use English as the default lang
439. vel 345 xinetd on sbin chkconfig level 345 tftp on These commands configure the tftp and xinetd services to immediately turn on and also configure them to start at boot time in runlevels 3 4 and 5 50 Chapter 4 Diskless Environments 4 2 Configuring the DHCP Server If a DHCP server does not already exist on the network configure one Refer to Chapter 24 Dynamic Host Configuration Protocol DHCP for details Make sure the configuration file contains the following so that PXE booting is enabled for systems which support it allow booting allow bootp class pxeclients match if substring option vendor class identifier 0 9 PXEClient next server lt server ip gt filename linux install pxelinux 0 where lt next server gt option should be replaced with the IP address of the tftp server 4 3 Configuring the NFS Server The shared read only part of the operating system is shared via NFS Configure NFS to export the root and snapshot directories by adding them to etc exports For example diskless i386 RHEL4 AS root ro sync no_root_squash diskless i386 RHEL4 AS snapshot rw sync no_root_squash Replace with one of the hostname formats discussed in Section 22 3 2 Hostname Formats Make the hostname declaration as specific as possible so unwanted systems can not access the NFS mount If the NFS service is not running start it service nfs start If the NFS service is already running rel
440. w the print spool queue as shown in Figure 34 14 Chapter 34 Printer Configuration 271 Printer Edit View Help Document Owner Job Number Size Time Submitted anaconda ks cfg root 1 2048 bytes Wed 18 Dec 2002 01 23 58 AM EST 1 job in queue printer Figure 34 14 List of Print Jobs To cancel a specific print job listed in the GNOME Print Manager select it from the list and select Edit gt Cancel Documents from the pulldown menu If there are active print jobs in the print spool a printer notification icon may appear in the Panel Notification Area of the desktop panel as shown in Figure 34 15 Because it probes for active print jobs every five seconds the icon may not be displayed for short print jobs COIL aso Figure 34 15 Printer Notification Icon Clicking on the printer notification icon starts the GNOME Print Manager and displays a list of current print jobs Also located on the Panel is a Print Manager icon To print a file from Nautilus browse to the location of the file and drag and drop it on to the Print Manager icon on the Panel The window shown in Figure 34 16 is displayed Click OK to start printing the file Printer Name CE Z Properties State Printer idle i Set as default Type Created by redhat config printer 0 6 x Location Comment HP LaserJet 4Si Foomatic ljet4 Page selection Copies All pages Number of copies 1 Pe M Collate copies C Pages
441. ww redhat com apps support errata e Via Quarterly Updates Refer to the following location for details 288 Chapter 37 Manually Upgrading the Kernel http www redhat com apps support errata rhlas_errata_policy html Via Red Hat Network Download and install the kernel RPM packages Red Hat Network can download the latest kernel upgrade the kernel on the system create an initial RAM disk image if needed and configure the boot loader to boot the new kernel For more information refer to http www redhat com docs manuals RHNetwork If Red Hat Network was used to download and install the updated kernel follow the instructions in Section 37 5 Verifying the Initial RAM Disk Image and Section 37 6 Verifying the Boot Loader only do not change the kernel to boot by default Red Hat Network automatically changes the default kernel to the latest version To install the kernel manually continue to Section 37 4 Performing the Upgrade 37 4 Performing the Upgrade After retrieving all of the necessary packages it is time to upgrade the existing kernel At a shell prompt as root change to the directory that contains the kernel RPM packages and follow these steps ion It is strongly recommended that the old kernel is kept in case there are problems with the new kernel Use the i argument with the rpm command to keep the old kernel Do not use the U option since it overwrites the currently installed kernel which creates boot loade
442. xplains these steps in detail 1 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 En terprise Linux Documentation CD using the Kickstart Configurator application or writing it from scratch The Red Hat Enterprise Linux installation program also creates a sample kickstart file based on the options that you selected during installation It is written to the file root anaconda ks cfg You should be able to edit it with any text editor or word processor that can save files as ASCH text First be aware of the following issues when you are creating your kickstart file Sections must be specified in order Items within the sections do not have to be in a specific order unless otherwise specified The section order is Command section Refer to Section 1 4 Kickstart Options for a list of kickstart options You must include the required options The packages section Refer to Section 1 5 Package Selection for details 2 Chapter 1 Kickstart Installations The pre and post sections These two sections can be in any order and are not required Refer to Section 1 6 Pre installation Script and Section 1 7 Post installation Script for details e Items that are not required can be omitted Omitting any required item results in the installation
443. y useful commands such as ssh scp and ping if the network is started dump and restore for users with tape drives parted and fdisk for managing partitions rpm for installing or upgrading software joe for editing configuration files Note If you try to start other popular editors such as emacs pico or vi the joe editor is started 56 Chapter 5 Basic System Recovery 5 2 1 Reinstalling the Boot Loader In many cases the GRUB boot loader can mistakenly be deleted corrupted or replaced by other operating systems The following steps detail the process on how GRUB is reinstalled on the master boot record Boot the system from an installation boot medium Type linux rescue at the installation boot prompt to enter the rescue environment Type chroot mnt sysimage to mount the root partition Type sbin grub install dev hda to reinstall the GRUB boot loader where dev hda is the boot partition Review the boot grub grub conf file as additional entries may be needed for GRUB to con trol additional operating systems Reboot the system 5 3 Booting into Single User Mode One of the advantages of single user mode is that you do not need a boot CD ROM however it does not give you the option to mount the file systems as read only or not mount them at all If your system boots but does not allow you to log in when it has completed booting try single user mode In single user mode your compu
444. yboard keyboard us System mouse mouse Sytem timezone timezone America New_York Root password rootpw iscrypted 1 J Y IY60H 0iJHzgLRsSmHPexaXoffed Reboot after installation reboot install OS instead of upgrade install zl O r 2 R Cancel GASaveto File Figure 2 17 Preview To save the kickstart file click the Save to File button in the preview window To save the file without previewing it select File gt Save File or press Ctrl S A dialog box appears Select where to save the file After saving the file refer to Section 1 10 Starting a Kickstart Installation for information on how to start the kickstart installation Chapter 3 PXE Network Installations Red Hat Enterprise Linux allows for installation over a network using the NFS FTP or HTTP pro tocols A network installation can be started from a boot CD ROM a bootable flash memory drive or by using the askmethod boot option with the Red Hat Enterprise Linux CD 1 Alternatively if the system to be installed contains a network interface card NIC with Pre Execution Environment PXE support it can be configured to boot from files on another networked system rather than local media such as a CD ROM For a PXE network installation the client s NIC with PXE support sends out a broadcast request for DHCP information The DHCP server provides the client with an IP address other network infor mation such as name server the IP address
445. your partitions automatically and they were mounted successfully you are in single user mode Even if your file system is mounted the default root partition while in rescue mode is a temporary root partition not the root partition of the file system used during normal user mode runlevel 3 or 5 If you selected to mount your file system and it mounted successfully you can change the root partition of the rescue mode environment to the root partition of your file system by executing the following command chroot mnt sysimage This is useful if you need to run commands such as rpm that require your root partition to be mounted as To exit the chroot environment type exit to return to the prompt If you selected Skip you can still try to mount a partition or LVM2 logical volume manually inside rescue mode by creating a directory such as foo and typing the following command mount t ext3 dev mapper VolGroup00 LogVol02 foo In the above command foo is a directory that you have created and dev mapper VolGroup00 LogVo102 is the LVM2 logical volume you want to mount If the partition is of type ext 2 replace ext3 with ext2 If you do not know the names of all physical partitions use the following command to list them fdisk 1 If you do not know the names of all LVM2 physical volumes volume groups or logical volumes use the following commands to list them pvdisplay vgdisplay lvdisplay From the prompt you can run man
446. ype in a character and then press the Tab key Your terminal displays the list of files in the directory that start with that letter key combination A combination of keystrokes is represented in this way For example The Ctrl Alt Backspace key combination exits your graphical session and returns you to the graphical login screen or the console text found on a GUI interface A title word or phrase found on a GUI interface screen or window is shown in this style Text shown in this style indicates that a particular GUI screen or an element on a GUI screen such as text associated with a checkbox or field Example Select the Require Password checkbox if you would like your screensaver to require a password before stopping top level of a menu on a GUI screen or window A word in this style indicates that the word is the top level of a pulldown menu If you click on the word on the GUI screen the rest of the menu should appear For example Under File on a GNOME terminal the New Tab option allows you to open multiple shell prompts in the same window Instructions to type in a sequence of commands from a GUI menu look like the following exam ple Go to Applications the main menu on the panel gt Programming gt Emacs Text Editor to start the Emacs text editor button on a GUI screen or window This style indicates that the text can be found on a clickable button on a GUI screen For example Click on the Back button
447. ystem users and groups from the pulldown menu 33 1 Adding a New User To add a new user click the Add User button A window as shown in Figure 33 2 appears Type the username and full name for the new user in the appropriate fields Type the user s password in the Password and Confirm Password fields The password must be at least six characters The longer the user s password the more difficult it is for an intruder to guess it and use it to access the user s account without permission It is also recommended that the password not be based on a dictionary term as well as the password be a combination of letters numbers and special characters 248 Chapter 33 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 by unselecting Create home directory If you select to create the home directory default configuration files are copied from the etc skel directory into the new home directory Red Hat Enterprise Linux uses a user private group UPG scheme The UPG scheme does not add or change anything in the standard UNIX way of handling groups it offers a new convention Whenever you create a new user by default a unique group with the same name as the user is created If you do not want
448. zing a Partition waming Do not attempt to resize a partition on a device that is in use Before resizing a partition boot into rescue mode or unmount any partitions on the device and turn off any swap space on the device Start parted where dev sda is the device on which to resize the partition parted dev sda View the current partition table to determine the minor number of the partition to resize as well as the start and end points for the partition print 94 Chapter 12 Managing Disk Storage A waming The used space of the partition to resize must not be larger than the new size To resize the partition use the resize command followed by the minor number for the partition the starting place in megabytes and the end place in megabytes For example resize 3 1024 2048 After resizing the partition use the print command to confirm that the partition has been resized correctly is the correct partition type and is the correct file system type After rebooting the system into normal mode use the command df to make sure the partition was mounted and is recognized with the new size 12 2 LVM Partition Management The following commands can be found by issuing 1vm help at a command prompt Create a logical volume lvmchange Due to use of the device mapper this command has been deprecated lvmdiskscan List devices that may be used as physical volumes Collect activity data Create activity report Ch

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