LINUX SYSTEM ADMINISTRATOR PRACTICAL
PRACTICAL NO :1 Graphical User Interface and Command
Line Interface and Processes
A) Exploring the Graphical Desktop
B) Basic Command
1.ifconfig
2. vim/vi :
Press i –> to write context
To quit and save – > esc :wq!
3. hostname :
4. chmod
First is symbolic mode
Second is octal mode
5. mkdir
6. a) ls
b) ls –a
7.cat
Cat > [filename]
To save and quit =crl+d
Concat 2 files and store in file
View the context of file
8. Pwd
9. Man
To exit =q
10. Cal
11. History
12. Touch
13. cp
14. mkdir
15. mv
rename the file using mv
16. rm
Remove forcefully = with contect
17. head
18. tail
20. sort
sort –n = by number
21. grep = to search the keyword in a context
To search that donot match the pattern = -v
To display the number line =-n
22. Runlevel
Practical No 2. Storage Devices and Links, Backup
and Repository
a) Mounting Unmounting Devices
1]To Mounting a Device
Connect your Device(Say Pen drive) and insert it.
To check in Virtual Machine, use ‘df’ command
b) Creating Links and Backups
Create a File using cat command : file Kitty .
Create a Symbolic Link
Checking the symbolic Link
Creating HardLink of a File
Delete and check the contents using hard link
b) Making a Backup
Create a Tar File
Go to check contents -> cd tmp , ls
For testing -> [root@localhost tmp]#tar -tvf /tmp/etc.tar
For Extracting
[root@localhost temp]# tar -xvf /tmp/etc.tar
c) Creating a Repository
Create a Directory with the Name of ‘repo’ using ‘mkdir’ command
For The Package Installing - > cd /media/RHEL_6.0\ i386\ Disc\ 1/Pakages/
Copy the Contents into ‘repo folder’
Creating own repository -> repo
Working with yum
cat /etc/yum.repos.d/rhel-source.repo
gedit /etc/yum.repos.d/repo.repo
yum search nmap
Practical No 3: Working with RPMs Storage and
Networking
c) Configuring and Managing Storage
Creating new partition
Command to inform kernel about new partition
Partition created
informing hard disk
Creating a directory
Mount the partition in /etc/fstab
unmounting created partition
Command to inform kernel to delete partition
Checking
C) Connecting to the Network
Run setup command [root@localhost Packages]#setup
Choose Network Configuration Choose Device Configuration
Choose eth0
Press space after coming to Use DHCP Configuration
Enter IP Address, Subnet Mask
Use ifconfig command
Practical No 4. Working with Users, Groups, and
Permissions
Adding user and changing password
Deleting the user
Making a normal user as a root user
Changing the password policy for the Acting root user
Lock and unlock password
Adding Groups
Practical No 6. Firewall and Cryptographic services
a Securing Server with iptables
List the current iptables
Remove all iptables rules
Change the default chain Policy to ACCEPT
For incoming packets:-
For outging packets:-
For forward packets:-
Change the default chain Policy to DROP
For incoming packets:-
For outging packets:-
For forward packets:-
Add drop rules For incoming packets:-
For outing packets:-
For forward packets:-
Allow incoming ssh connections from specific IP address
Iptables to reject incoming ssh connections
Allow incoming ssh connection
Allow outgoing ssh connection from a specific IP address
Allo
w outgoing ssh (ESTABLISHED state only) connection (for the corresponding incoming
SSH connection request)
Iptables to drop incoming ping requests
Iptables to drop outgoing telnet connections
Iptables to reject outgoing telnet connections
Practical No 7. Configuring Server for File Sharing
a) Configuring NFS Server and Client
Setting Up NFS Server: Verify the package of NFS whether installed .
Verify IP address of the linux machine to be set up as NFS Server:
Make a directory to be exported , create few files into it and give it full
permission
Open The configuration File and write the following lines under it:
and restart the nfs service.
Stop the Firewalls and check the status whether it is stopped
Showmount command shows you all shared directories in given IP address.
-----showmount -e 192.168.1.3
As NFS Client make a directory /clientnfs and mount the server exported
directory on it.
Try to create new dile in client side.
b) Configuring Samba
VmNet1 configuration
Vmware configuration
Go to Packages Folder, and install samba with rpm command
To query whether samba packages installed
Go to home directory, create folder tysamba
Create files using touch or cat command
1. Also give this directory full permission.
2. Open the configuration file
On line 74 change MYGROUP-> workgroup
On line 79, change IP address as shown below
Go to the last line and edit the changes
Start the samba services
Use testparm command
Block firewalls
To give temporary read only permissions
In this file home directory is off To make it on copy first line and paste with setsebool
command as follows
Start and restart smb services
Create a samba user and assign password
Start and restart smb services
In windows, go to start-> run and type
Goto Windows Run Command Typeping192.168.1.3–t and Check whether reply
and response is working fine
Now to check whether files are been transferred from Samba to Windows Run- >\\192.168.1.3
c) Configuring FTP
Verify the if all 5 packages vsftpd for FTP is installed :
Only 3
If not installed do below command.
All 5 nfs packages installed
Now use following command to start vsftpd services at boot time using
chkconfig command.
Verify IP address of linux machine to be configured as FTP.
Open the configuration file and make the following changes:
1. Uncomment anonymous_enable=YES
2. Uncomment local_enable=YES
3. Uncomment anonymous_upload_enable=YES
4. Uncomment listen=YES and restart vsftpd service.
Login with anonymous user. Now you can login with ftp192.168.36.129
We can use Username: anonymous and password for same is blank.
Here you can use ls–a command to view the content of ftp home
directory.
Now allow ftp anonymous write enable
o setsebool–Pallow_ftp_annon_write on or=1
Allow System user to get access to ftp server.
o setsebool–P ftp_home_dir on
verify it
By default /var/ftp is ftp user Home directory. Check the context offile
/var/ftp/pub and change to ftp
Now go to pub directory and create one file.
Restart the service of vsftpd and enable it from boot. Also give full
permission to the directory/var/ftp/pub.
Now FTP is configure. Test as FTP client from other machine.
PRACTICAL NO 8: DNS, DHCP and Mail Server
a) DHCP
First we have to check whether DHCP is available on our machine or
not that we can check with rpm command.
Go the Packages Folder and install dhcp
Check the hostname of the server
To assign IP to dhcp server DHCP server have a static IP address. First configure the IP
address192.168.1.3with netmask of 255.255.255.0 on server.
Right Click on network icon. Select Edit Connections
Select System eth0
Edit the Connections
select DHCP
To Restart the network,
Open The configuration File dhcpd.conf
Copy the files
Open the Configuration file
Change domain-name to vignesh.com and option-domain- name- server to server.vignesh.com
Uncomment Line 18
Comment line 27 and 28
Make the Change as shown Below
Save the File
Start dhcp service
stop Firewall
Stop dhcp server
To Create a Clone, we right click on the virtual machine, click Manage and then click Clone
Open Clone Machine
Right Click on Network Icon, Select Edit Connection, select system eth0
From clone Machine,
C. Setting Up a Mail Server
Install postfix
Configure to work at boot time
Edit the configuration file
Following changes needs to be done:
Restart postfix service
Stop the sendmail service
Compose mail
Login from Roman
Practical No 9. Web Server
a Configuring Apache on Red Hat Enterprise Linux
Client side Go to the clone and open browser and type http://ip add
Practical No 10. Shell Scripts
a Use of echo command, Use of comment, Using While loop, Using
For loop, GetUser Input, Using if statement, Using Case Statement.
Shell Script :
Execute the Script :
