This morning we got nets to set up B047 on the switch. Some time after that 3 machines lost the ability to get a DHCP address - I have no idea if there is a causal relationship between these things.

After much mucking about, it *looks* like it might have been a communication problem between the DHCP server and the machines.
Even forcibly releasing the DHCP lease didn't make any difference.

In the end, I booted the machine with a LiveCD and fiddled with enabling/disabling the network (in the network manger). I got a proper IP and rebooted in the installed OS. That seemed to break it out of the loop.

A bit perplexing and aggravating because I don't actually know what the problem was...