DHCP oddness

[Bart Silverstrim]

Anyone experience anything like this?

I have Ubuntu Feisty-Beta running on a Dell Optiplex GX260.  Because  
of a quick fix job that had to be done, the hub the system was  
plugged into was removed, so the system was running but didn't have  
network access.

When I got back I plugged the system into a wall socket for network  
connectivity instead of going into the hub it was on before.  While  
it would say it was on a wired network, DHCP would *not* pull a new  
address.  I shut down the interface (ifconfig eth0 down) and brought  
it back up, still nothing.  I switched patch cables, still nothing.   
Only rebooting the computer allowed it to correctly pull an address.

Anyone run into this before?

-Bart