Linux Administration

Pre-Install Different distributions –Redhat, Caldera, mandrake, SuSE, FreeBSD Redhat Server Install –Check HCL –Significant issues Stability, availability and performance Avoid games, casual users, anonymous ftp, telnet Allow access via secure shell, secure ftp and firewall policies Avoid Xwindows unless needed by user at console Watch out - runaway daemons will eat your cpu

More pre-install options Dual-booting –Need separate partitions for all OS you plan to run Fips.exe for repartitioning FAT Install windows First, Linux afterwards Install Options –CDRom (boot.img) or over the net (bootnet.img) If install fails –Kernel panic You don ’ t need to panic ! Its almost always Hardware issues. –Check cdrom for CRC errors –Check HCL

Installation Boot.img –For CDROM install Type text for text based screen Hit enter for GUI based (If video card is pretty decent) –Select language, keyboard and mouse To Reconfigure –/usr/sbin/kbdconfig (keyboard) /usr/sbin/mouseconfig (mouse)

Creating Partitions Partitions are mounted at boot time / is the root directory Common partitions –/usr For program files –/home Home directories for users –/var Log files and system messages –/tmp Temporary files. Monitor to avoid, filling up the entire hd –Swap Not a file-system. Used as virtual storage and paging Double the RAM if less 128Mb or same as RAM is more than 128Mb.

Boot Manager Handles the actual load process of the OS –Same as NTLDR (windows NT) –LILO –GRUB Where to setup the boot manager ? –MBR (Master Boot Record) BIOS uses POST for hardware checking and passes control to MBR. The software in MBR is loaded –First sector of the boot partition Select this if you are using another boot loader –Preferred boot loader runs first and passes control to LILO/GRUB if you decide to start linux. LBA (Logical Block Addressing): –Used by SCSI devices

Network Config and User List Ethernet cards are numbered –eth0, eth1, eth2 –Configurable as DHCP or static User list –/etc/passwd Cannot login unless the user has an entry NIS for remote user authentication –/etc/shadow Encrypted passwd file Supports long passwords – upto 256 char Supports different encryptions –MD5, blowfish

Configuring X X Windows: –Basis of linux gui –Communicates with the actual video hardware. –Numerous programs that use X KDE, GNOME, Enlightenment, Sawfish –Decoupled from the base OS Possible to load OS with out starting the GUI Saves memory and system resources –Xorg Version of X used by linux. –Xfree86 (older version) Auto detects video card and monitor Manual configuration if card is not identified –Requires user to know frequency monitor, refresh rates, memory on video card.

Common Commands #linuxconf & –For most administrative tasks Manage users, passwords, network configurations, devices #ps –ef | grep more –See all running processes. #kill –Kill a running process (kill ) #man –Documentation (man ls) #ls (folder, file listing) #chgrp (change group) #chown (change ownership) - p:384 for permissions #gzip, #tar (to compress files) #du (disk utilization)

Useful Commands Su (switch user) –Change user Uptime –Tells how long the system has been up. Xconfigurator (redhat 8 or lower) –redhat-config-xfree86 (redhat 9) –Configure display Mouseconfig –Configure mouse Setup –Fire wall, ports, display manager, audio