UNIX for Advanced & Expert Users

Hello....weird problem but hoping someone can help!

Server: PowerEdge 2850 - 8 core - 12gb ram - 32 bit processor
OS: Redhat ES 6
Setting: University setting .. use server for Computer Science student accounts (350 users)

Every so often the system just boots you, no matter what you are doing. Has happened to me as well when editing a file or just sitting at the command prompt.

Most users use putty to connect, though I have used SSH Secure Shell as well, get booted with both.

Things I have checked or done:

Changed out ethernet cables, changed out the ethernet card. Fiddled with the number of user processes, number of system logins etc.

Have looked at settings in sshd.config relating to Timeouts.
Have connected machine to a different physical switch.
Have increased user limits.


Anyone have any ideas what might cause the system to just boot users randomly like this?

What is your network topology?

It is a switched class B network, much like other Universities. My server is connected to a Netscreen firewall which in turn is connected to a switch in the building. I have about 6 other servers which are all configured the same way and none of them see this problem. This leads me to believe that it is possibly a motherboard problem?? but i dont know of any way to prove/disprove that.

Does this netscreen firewall act s a router? i.e. do you end up on a different subnet than the school network?

If so I suspect it is the problem. Hardware routers often have tiny connection tables, and enforce draconian connection timeouts to keep it from filling up.

no, it doesnt do any routing at all. I actually bought a new firewall as well hoping that would fix the problem but the problem was there with the new firewall as well.

New firewall as in different kind of firewall, or new firewall as in identical replacement?

It is still a netscreen but a newer version...old one was a netscreen 5GT and new one is a netscreen SSG5