NIC goes down upon Gnome logout

[Ryan Jacobs]

Hello!

I represent a small non-profit organisation based in Tshwane, South 
Africa. We use Ubuntu as both a server and desktop within our office, 
and the question I have is in regard to the server...

We setup an internal (non-public) dedicated Ubuntu server for 
file-sharing/printing (via samba), backups (via backuppc), small 
firewall and net monitor, etc... This installation was based on a 
default Warty install over a year ago. Now, after upgrading this install 
to Hoary, we have discovered a strange issue:

If I login as an admin user directly to the local Gnome interface, and 
later logout back to the default graphical welcome/login screen, one of 
the servers NICs dies (upon logout). "Dies" is the only term I can think 
of because logging back in and checking the status shows that it's 
enabled, and an ifconfig shows that its retained it's setting and is 
active. However, pinging anything through this NIC (from outside to the 
server, or from the server outside) simply fails. The only way to get it 
working again is a reboot.

Most of our server admin is done through an ssh connection, but 
occasionally it's nice to access the interface as an admin. However, if 
doing so continually kills the whole network, then this seems like a 
rather fundamental problem, and may mean there are other issues as well....

My concern is that this problem only started after upgrading to Hoary, 
and that I really don't know how to troubleshoot it. This is why I am 
hoping someone might point me in the right direction to start. What 
actually "happens" when you logout of Gnome... it's not as if runlevels 
are changed or anything, are they?

Any help would be greatly appreciated.

Cheers,
Ryan Jacobs