Problem in "Debian system" as web and mail server and NIS client
I set up a web and mail server that is running on Debian 6.
This server is a NIS client system also where all NIS user's (students) files system is mounted using NFS from the NIS master.
My NIS master runs on SUSE 11.4.
Now some users(not all) are unable to ssh to web server and could not able to login to the squirrelmail account as well.
However, they are able to through NIS client machines without any problem.
All client machines have SUSE 11.4 operating system.
What can be the problem behind, not able to ssh and webmail login?
The specific users are facing both problems at same time not one at a time.
Please suggest me some ways to tackle the problem.