1.  What is command to determine File System Types?

 [root@local]#  df -T
Filesystem    Type   1K-blocks      Used Available Use% Mounted on
/dev/sda1     ext4      495844     36118    434126   8% /boot
/dev/sda3     ext4   476186680  72478892 398871248  16% /
tmpfs        tmpfs     1013176      1156   1012020   1% /dev/shm

2. What is ethernet Bounding ?
Ethernet bounding is used to combine multiple interfaces into one, creating an increase available bandwidth and redundancy. This is done by creating a special network interface file called a channel bonding interface

3. When troubleshooting TCP Wrappers where do you find out ?
We can use the /var/log/secure file to view information from the log file. Its very helps to determine if something is wrong with specific details.

4. How do you allow SSH login a single ip address?
Yes, it’s possible to allow only a single IP address to be able to connect the server, Open /etc/hosts.allow by any text editor (vim,vi,nano) and add the below line like this:

sshd :

5. How do you allow SSH port number through Iptables?
# iptables -I INPUT -p tcp -m tcp --dport 22 --dport -j ACCEPT

-I          => Inserting Rules
- INPUT => Input chains
-m        => matching only TCP connections
--dport  => Incomming connections
-j        => Jumping the acceptance chain to all the locate    
-p       => Protocol (tcp)

6. SSH enforcing password length and complexity?
Both the pam_cracklib and pam_passwdqc modules are used in enforcing password length and complexity

7. How do you validate the syntax of the Apache config file?
# service httpd configtest

8. What are the two main NFS security types?
host-based security
user-based security

9. What command is used to dump a mysql database?
Mysqldump –u root –p password database_name > backup_database.sql

10.    What does the testparm command do?
The testparm command is used to check syntax errors in the /etc/samba/smb.conf file.

Interview Questions-1
Interview Questions-2
Interview Questions-L2