Comment 5 for bug 213937

I'm using NetworkManager and have the same problem: The network doesn't start and the reason seems to be because eth0 doesn't get the IP address. After I run either "sudo /etc/init.d/networking restart" or "sudo ifdown -a && sudo ifup -a" everything works fine. Part of the output is:

There is already a pid file /var/run/dhclient.eth0.pid with pid 134519072

My network setup worked before in Gutsy.