Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

My main PC has AN Athlon X2 4600+ on an Asus M2npv-vm. Has been working fine for ages running Ubuntu. Today it the system locked up and I had to do a reset. Since then it will not connect to the router or cable modem. I can connect another PC to the router, so that looks okay.

What can I do to test the network connection from Ubuntu? It's not even getting an IP.

I suppose it could be something has died in the hardware, but want to eliminate other possibilities first.

share|improve this question
what does the output of "ifconfig" say ? Also, try "sudo dhclient eth0" where eth0 is the interface name. – Abhinav Jun 20 '10 at 19:31

Got it working using the following sequence of commands. Use sudo on all

service network-manager stop
rm /var/lib/NetworkManager/NetworkManager.state
service network-manager start 
share|improve this answer
+1 self-answers are good for SU. – msw Jun 20 '10 at 22:17

This helped me multiple times (Ubuntu 9.10,10.04,10.10 + Gnome):

  • Right-click on network icon at gnome panel
  • Turn "Network" on.

For some reason, network is switched off on system crash or non-clean poweroff. Removing NetworkManager.state file as Steve suggests also does the trick, as default state with everything "on" is used.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.