Linux System Configuration and Administration

Lecture 6: Linux Configuration and Administration

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Organization of the Talk

Installation of Linux System Configuration

Network configurationSharing with WindowsPrinter ConfigurationSome security configuration

AdministrationsUser ManagementUser home pages

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Installing Linux: Where do you start Is Your Hardware Compatible?

http://hardware.redhat.com/hcl/ Do You Have Enough Disk Space?

You have to decide, remove any virus if required, use fips

Can You Install Using the CD-ROM? Your BIOS may need to be changed to boot

from your CD-ROM Alternative Boot Methods

Boot Diskette Driver Diskettes

Network Device Drivers Diskette3

Gather more info Use ‘other’ OS to

know morePersonal Desktop

Installations Learning About

Your Hardware with Windows

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Graphical Installation The Graphical Installation

Program User Interface (text mode is also available) Choose the language,

keyboard and mouse

Choose upgrade or new

installation Better to choose fresh

installation

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Installation of Linux…•Choose personal desktop installationFor the first, but next time you bet on Custom

•After all Linux is knowing more

Choose partition

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Installation of Linux…• Configure the partition:

• Set the mount point• Set the SWAP size• Set the /boot space • Enable Ext3 formatting

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Installation of Linux…Choose the boot loader Grub or Lilo

• Configure the “Network Configuration”

• DHCP, Firewall, IP address etc..

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Installation of Linux…Choose the “Root password”

Accept the default package selection or customize using the “Customize option”

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Installation of Linux…

Installation starts and go on inserting the required CD when asked10

Post Installation

Create a boot diskette

Configure your video card, monitor and screen resolution

Reboot and start your Linux….! 11

System Configuration The kickstart file is a simple text file, containing a

list of items. It allows easy installation[2] and consistent configuration of new computer systems.

Kickstart Configurator Kickstart Configurator allows you to create a

kickstart file using a graphical user interface, so that you do not have to remember the correct syntax of the file.

To use Kickstart Configurator, you must be running the X Window System. To start Kickstart Configurator, select the Main Menu Button (on the Panel) => System Tools => Kickstart, or type the command /usr/sbin/redhat-config-kickstart.

As you are creating a kickstart file, you can select File => Preview at any time to review your current selections.

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System Configuration… Network configuration

• Networking can always be configured after installation with the Network Administration Tool (redhat-config-network).

• For each Ethernet card on the system, click Add Network Device and select the network device and network type of the device. Select eth0 as the network device for the first Ethernet card, select eth1 for the second Ethernet card, and so on.

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Printer Configuration

Menu=> Printing=> New Printer => choose the printer and printing tool (e.g. Post script printer)

Testing printer Just do lpq to see printer status

Lpr <filename> Should print the file

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Printer Configuration Useful Websites http://www.webopedia.com/TERM/p/printer.html

General denitions of printers and descriptions of printer types.

http://www.linuxprinting.org A database of documents about printing, along with a database of

nearly 1000 printers compatible with Linux printing facilities.

http://www.cups.org/ Documentation, FAQs, and newsgroups about CUPS.

http://www.tldp.org/HOWTO/Printing-HOWTO/index.html The Linux Printing-HOWTO from the Linux Documentation Project.

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User SecurityAuthenticationIn the Authentication section, select whether to use shadow passwords and MD5 encryption for user passwords.

The Authentication Configuration options allow you to configure the following methods ofauthentication: NIS, LDAP, Kerberos 5, Hesiod, SMB, Name Switch Cache

These methods are not enabled by default. To enable one or more of these methods,click the appropriate tab, click the checkbox next to Enable, and enter theappropriate information for the authentication method.

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Network Security Firewalls

Choose between High, Medium, and Disabled

security levels.

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Network Security Common Access control system

/etc/hosts /etc/hosts.allow /etc/hosts.deny /etc/hosts.equiv

For more info refer docs on iptable, firewall

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Sharing With Windows SMB protocol to share files and printers

across a network connection. Operating systems that support this protocol include Microsoft Windows (through its Network Neighborhood), OS/2, and Linux.

SMB implementation in Linux is called samba There are two things one can do

Share your files/printer with other windows machine

Access windows shared printer/files on linux

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Allow Windows to share You need to start samba server and nmb

server /etc/rc.d/init.d/smb start

What ever you want to share is added in /etc/samba/smb.conf Every change in conf file require restarting of server

Just browse OR find computer from windows to see these files/folders

You can share folders, CD, printer

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To access windows share Smbclient is a samba client

Smbclient –L myhost to see all share Smbclient \\\\myhost\\myshare

This will login to share and you can access the share

\\\\myhost\\printer can be written to print files Smbmount can be used to mount (map)

folders on to local host Smbumount to unmount

There are tools (GUI) for both sharing and accessing files

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User Management

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User Management

Simple way to add user is adduser command

Passwd will allow to change the passwd Of course there are host of GUI tools for all

these user management Group all common user to single group Be careful while editing /etc/passwd

/etc/shadow passwd file may also exist

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User Management

Common files to look at /etc/passwd /etc/group /etc/shadow /etc/samba/smbusers

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Web server on Linux

Apache server is mostly available on LinuxRpm –q –all | grep apache to check

This can be started via init services /etc/rc.d/init.d/httpd start

Configuration files are at /etc/httpd/conf/ Normally log files at /var/log/httpd

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User home pages

Will allow user to have home pageshttp://myhost.com/~user1

Need to edit /etc/httpd/conf/httpd.confEnable UserDir public_htmlAny user can have their page at public_html

Eg. /home/user1/public_html for user1 /home/user2/public_html for user2

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System maintenanceUsing package manager

Package Management Tool Because people use their

computers differently, users might want to install or remove packages after installation. The Package Management Tool allows users to perform these actions.

RPM is good package management tool in RedHat Linux

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System maintenance (redhat) The X Window System is

required to run the Package Management Tool.

To start the application, go to the Main Menu Button (on the Panel) => System Settings => Add/Remove Applications,

Type the command redhat-config-packages at shell prompt.

Command line tool rpm

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Lost Root Passwd

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Lost Root Passwd If you have Lilo installed, type

LILI: linux init 1 Change the root passwd, reboot aga

If you have installed grub Type ‘e’ to go to edit mode, add init 1 argument at the

end Boot with knoppix or single floppy linux

Mount the disk and change root passwd Reboot !!

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Cost Effective Linux Solutions

You have PC, with less harddisk for dual OS You have PC, on which you do not want to

install Linux Good heaven's do not do that

There is a spurt of Linux PC requirements for short duration of time For Linux LAB in one term OR during LAB

examinations

You have old PC, with out sizable hard disk

So you need Linux host for all the above case

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Cost Effective Linux Solution

Some most easy approachNetwork bootingSingle CD LinuxSingle floppy Linux

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Network Booting No need for harddisk(or harddisk with

Linux) on every host High level work flow

The system boots up, may be with floppy (could be with hard disk also)

Sends dhcp request for IP number, gets oneMounts the root file system over NFS

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Requirements for Network Booting

Setup an LAN infrastructure Need to setup nfs server Need to setup dhcp server Build a kernel image for network booting

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Setup an LAN infrastructure

Ethernet Cable

Hub Ethernet Cable

Your m/c to be booted

Your host, NFS server and DHCP server should be on same LAN

NFS server

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Setup nfs server

• Edit /etc/exports file before starting the nfs server.

• /     10.114.7.115(rw,no_root_squash)• This will export all files with root r/w to host

10.114.7.115• Save your exports file and from the prompt

execute exportfs command• Start the nfs server (nfs daemon)

• E.g. /etc/rc.d/inid.d/nfs start

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Setup dhcp server Add in your /etc/dhcpd.conf before starting the dhcp server.

Set the correct MAC address in /etc/dhcpd.conf as follows:

subnet <subnet address e.g.10.3.31.0> netmask 255.255.255.0 {}subnet 10.10.10.0 netmask 255.255.255.0 {

host master {hardware Ethernet <Mac address of your Ethernet card>;fixed-address <IP address of your machine e.g.10.10.10.1>;option root-path <your root path>”;

}} Save your /etc/dhcpd.conf file start the dhcpd dameon by “/etc/rc.d/init.d/dhcpd start” command

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Build a kernel image for network booting

Linux Kernel compilation steps: Assumptions: machine x86 (i386); boot loader lilo.   Get plain vanilla kernel from www.kernel.org Explode it into a directory (better if can do it in /usr/src/) => tar -zxvf

linux-2.x.xx.tar.gz Optional: create a symbolic link ln -s  linux-2.x.xx linux cd to linux directory cd /usr/src/linux or cd /usr/src/linux-2.x.xx Select the components support by make menuconfig or make xconfig  -

save the configuration Select IP:BOOTP support from Networking options In File system -> Network File System -> Select

NFS File system support and Root file system on NFS

Do Make dep bzImage Make modules modules_install

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Build a kernel image for network booting…

Copy the /usr/src/linux/arch/i386/boot/bzImage to /boot

Do mkbootdisk with new kernel as argument

Optional take a coffee or tea break ?

     

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Putting all together..

Make sure you are running dhcp server

Make sure you are running nfs server

On any PC that need Linux for temporary timeBoot with new floopy you just madeThat’s it !!!

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Knoppix Single CD Linux Knoppix is full Linux on a single CD Can be freely downloaded from

www.knoppix.com Just make your PC to boot from

CD, that is all required Your current software (OS) on your

system will not be lost If there is less memory, you can create

temporary swap on dos partation You can access dos partation

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Knoppix more info Hardware Requirements

Minimum of 486 PC, 20M ram for text mode, 90M for graphics mode and128M for office suite

Bootable CD drive + key board, mouse, multimedia

Software available 2.4 kernel, standard drivers, development tools,

Internet applications, multimedia applications Upto 2GB worth software in total

How to load/install start Step 1 put the 'cd' in drive, switch on the power

All the configuration is “auto” Step 2 Enjoy working on Linux

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Knoppix can be handy

The fact is you need not install Knoppix on harddisk So can be used in Demo of linux or software on

Linux So you need extra Linux machine lab ?? 2 minutes !! No extra space on harddisk on old PC's, just use

knoppix Got a new laptop, just boot Linux on that in a jiffy

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Knoppix in Emergency

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Knoppix at emergency

Lost root passwd, boot knoppix, mount the harddisk, edit /mnt/etc/passwd, reboot old linux Can be dangerous, spurious user can do the same

Linux do not boot, boot with knoppix and recover the important files Best part is you also recover lost dos/windows files

as well

You have screwed up your configuration Boot with knoppix and bring back to default

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Single Floppy Linux

Similar to Knoppix, but over a floppy Will have much lesser applications Some distributions come with two or more floppy

MuLinux quite esay to use http://mulinux.nevalabs.org/

Coyote linux: mostly for network applications http://www.coyotelinux.com/

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References Chetan Kumar S “Power Linux – Unleash the full potentials of Linux”, BIET,

Davangere, Wipro Technologies http://www.tldp.org/ (The Linux Documentation Project) : It contains a lots and lots

of well documented and timely documents to learn and trouble shoot your Linux system (it’s free) http://www.tldp.org/guides.html

The Linux System Administrators' Guide Lars Wirzenius, Joanna Oja, Stephen Stafford, and Alex Weeks It’s free and available at http://www.tldp.org/guides.html

The Linux Cookbook: Tips and Techniques for Everyday Use Michael Stutz It’s free and available at http://www.tldp.org/guides.html

The Linux Network Administrator's Guide, Second Edition Olaf Kirch and Terry Dawson It’s free and available at http://www.tldp.org/guides.html

http://www.redhat.com/docs/

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Thanks

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