Comment 2 for bug 19740

I have a very similar experience on my Breezy box. I guess it's the same problem
underneath so I'll just follow up here. Note that my Hoary installation was
working fine all the way so this was probably not ISP/router related.

After an upgrade a week or so ago my network stopped working. More precisely my
eth0 interface did not come up. It didn't show up when I ran "ifconfig",
although it showed up with a "ifconfig -a".

Poking around I tried "sudo ifup --verbose eth0", but it just stalled with no
output what so ever. Suddenly after a few days it started working again. I don't
think I really did anything to make this happen... I did a dist-upgrade and the
network failed again. From the forums somebody pointed me to "dhclient", and
"sudo dhclient" brings up my network.

As it is now, I have to run "sudo dhclient" after each boot to get my network
running.

PS: The network-admin UI does not seem to be able to handle this problem.