Wednesday, August 13, 2008

Notes Chapter 6:System Admin Task

8:55 AM 8/13/2008

Chapter 6 :System Admin Task

_________________

-Setting the run level
-system services
-user management
-network setting
-scheduling jobs
-Quota management
-backup and restore
-adding and removing software/package
-setting a printer
-monitoring the system(general,logs)
-Monitoring any specific services

running,.EG:DNS,DHCP,Web,NIS,NPT,Proxy etc..

3 types of backup
_________________

1) Full backup
2) Incremental backup
3) Differential backup

INIT RunLevels
______________

The following runlevels are define in Linux:

0- Halt(Do not set initdefalut to this)<--critical part

1- Single user mode(in safe mode,single user mode,can do the system

administrator task,main level mode)

2-Multiuser,without network(the same as 3 ,if you do not have

networking,can permit other client to join)

3- text Mode

4- unused(reserved for new development )

5- graphical Mode(GUI Mode)

6- Reboot(Do not set initdefault to this)<--critical part

The Default runlevel for a system to boot to is configured in

/etc/inittab

eg : id:5:initdefault:

In GUI :Application --> System Setting -->Server Setting --> Services

Linux Services
_____________

There are 113 daemons(services that running in the background),Out of

them the following are most widely used
*in linux,we manipulate the daemon to become the server

1)apmd : Power Management
2)Autofs :Automount Services
3)crond :Periodic Command Scheduler
4)cups :common Unix Printing System
5)dhcpd :The DHCP server
6)dovecot: IMAP (internet message Access protocol) and PP3(post office

protocol)server
7)gpm :mouse
8)httpd :Apache web server


iptalbles :Kernel based packet filtering firewall
kudzu :finds new hardware
mysqld :MySQL server
named :BIND server
network :networking
nfs :Network file share
nfslock :NFs file locking
ntpd :NTP (network time protocol)Server
portmap :RPC(Remote procedure Call)Support
postgresql :The prostgreasql Database engine
sendmail :Sendmail mail server
smb :Samba network services
snmpd :Simple network management protocol
squid :Squid proxy server
sshd :open SSH and SFTP server
syslog :system logging
xinetd :(Super Daemon),provides suppor for telnet
ypbind :NIS server

Start/stop boot time services /etc/rc.d/rc3.d or /etc/rc.d/rc5.d

All services startup scripts which start with S will start at boot time

and all startup scripts which start with K will not start.

Creating a new user account
___________________________

#useradd

add an entry in /etc/passwd and /etc/shadow file.You will have to

create the user directory and assing a pssword to the user

/etc/passwd File holds user account info

login name
user id
group id
shell

/etc/shadow contains the encrypted password information

Suspending a user account
_________________________

-put a * as start of password field in /etc/shadow
-change login shell to /sbin/nologin
-use GUI to suspend user
Remove user id
______________

#userdel -r- (username)


*Assignment:
Submit next wednesday
Find Run level Linux

No comments: