UNIX for Advanced & Expert Users

What does

Code:

dmesg

have to say - right after someone get booted?

Code:

 /var/log messages

? (or whatever you have configured)

If you get disconnected what does

Code:

netstat -a

show -

Code:

TIME_WAIT

for high number ports like 49152?

I can't know but I think there is a network disconnect going on.
Try connecting to the console on the server. If you can stay connected for several days (or whatever you deem reasonable) then that asserts it is probably related to the network.

Does your firewall have logs - does it timestamp when a given action is taken - deny, block ,etc? Is there any correlation there with the "boot-off" problem?

Do you have the TMOUT variable defined?

well i too have pointed the finger at network as well. Unfortunately our network folks arent very co-operative as they take it somewhat personal. the only messages i ever see are in /var/log/messages

Code:

messages:Dec  9 19:53:02 student kernel: e1000: eth1 NIC Link is Down
messages:Dec  9 19:53:04 student kernel: e1000: eth1 NIC Link is Up 100 Mbps Full Duplex, Flow Control: None

which tells me the network was restarted for some reason...however those messages arent on any of the other servers which sit right beside the one in question. So the million dollar question is what is restarting the network? Is it the physical network or the OS?

Ah, if it thought the cable was unplugged, that would certainly kick all your network connections!

That doesn't look like an OS problem. I don't know of any way for a software problem to cause that message.

You've already ruled out most of the rest of the network as well as the firewall, leaving either the cable between server and firewall or the NIC itself. My guess would be a bad network card in the server.

well that is what i thought so i replaced both the cables and the network card. But the problem is still there with the new network card.

What does the firewall box show in logs/whatever. Does it see network down?
Or did I miss that the firewall is just a software add on?

Our CISCO firewall runs in a monster blade server <- where I'm coming from.

I don't see anything in firewall logs that pertain, maybe I should go back through the log configuration and se how they are set up. Thanks! that might be a good next move anyway.

The OS RHEL 6 has Network Manager component which manages the Networking and it works great in dynamic ip assignment. It is a pain if its on in the context of static ip assignment. Ensure that it is turned off and see if the problem persists.

Code:

chkconfig --list NetworkManager