Howto: Troubleshoot MCP-55 Ethernet on Ubuntu Jaunty 9.04
I installed a fresh Ubuntu Jaunty on a desktop and couldn’t connect to the local area network (DHCP). I tried the following tweaks, and finally it worked.
options forcedeth msi=0 msix=0
sudo rmmod forcedeth sudo modprobe forcedeth sudo /etc/init.d/networking restart sudo dhclient eth0
During the last line, the ethernet will start listening and start DHCPDISCOVER on eth0. I clicked the network manager to reattempt a connection and it worked.