What is the use of DNS Server? Name other servers works same as like DNS?

What are the main diff bwn Yum & rpm?

What are the main diff bwn NFS and Samba Servers?

What is the command to change from /etc/passwd file to /etc/shadow file?

diff b/w spinlock, seamaphores and mutex and where to use it.

Intel,

what are the steps for Password-less ssh

IBM, Mind Tree,

How to know what are the packages required for any service? Example: How to know what are the package required for send mail services. using any command it is passable are not?

OnMobile,

User unable to login in server then how can u troubleshooting it? Example: server at Bangalore. in that server two users try to login in server. 1st user able to login. but second user unable to login so how can troubleshoot it ?

Oracle,

User unable to login in server then how can u troubleshooting it? Example: server at Bangalore. in that server two users try to login in server from other place. 1st user able to login. but second user unable to login so how can troubleshoot it ?

Oracle,

1.how to know cpu information on linux system? 2.how to hardware information on linux system? 3.if we add the new user what are the files will be changed? 4.how to remove the cache in squid server ? 5.how to know ur useing 32bit r 64 bit os ? 6.at booting process at init level which file it is reads? 7.if ur system performance is show what can u do ? 8.if ur file system corrupted what can u do ? fsck also not working? 9.how did u do health check in linux? 10.how did u check system performance in linux? 11.how did u create NIS server? give me the steps ? 12.how did u add a packages in linux ? 13.how did u know depended packages for any package useing rpm how u know? 14.how did you monitor cronjobs in linux ? 15.what is the use of logroted? and how did u do ? 16.port no is already in use so what canu do for that in http? 17.how to samba configurated are not ? there are any command for that ? 18.how to create a NTP Client using commands ? not as graphical... 19.how to know how many members are using any service? like ftp are any other services? 20.what is the differences between cmp,diff,comm commands?

A system has four NI cards , how do you find out that a particular NI card is faulty without going to the sever ?

HCL,

what is block device and character device?

1. User gaves df -h and the system get hanged. why ? 2. what is the hardlink and softlink mount ? 3. why is portmape should be started ? 4. what is nologin option 5. how to restrict users from accessing nfs ? 6. what is the difference between cpio and tar 7. what are the kernel parameters ? how to find out it ? 8. why we use sysctl.conf ? 9. if we gives init1 from multiuser runlevel, will it affect other users who already logged in to the system ? 10. what will be the available space to use after configuering raid5 with 5 disks each having 5gb spce ?

Oracle,

what is kernel parameters? where its located and how would you find it ?

Oracle,

what is kernel panic error ? how will you fix it if you have face it after rebooting without the the help of rescue disk ?

Oracle,