In my case DNS resolution was working on and off randomly, in a clean 12.04 install. It was driving me nuts.
I do have my wireless DNS servers set manually to 208.67.220.220, and 208.67.222.222 in Network Manager.
Issuing:
Code:
dig askubuntu.com
would not return any IP address.
But:
Code:
dig askubuntu.com @208.67.220.220
always work.
After commenting out dns=dnsmasq in NetworkManager.conf and restarting it with
Code:
sudo restart network-manager
the situation was the same. Erasing that line and restarting Network Manager wouldn't change the situation. After rebooting the computer the computer won't resolve any address, and dig will show the DNS request was made through 127.0.0.1 (which was weird).
Anyway, the only way I found to solve the situation was removing and purging resolvconf with:
Code:
sudo apt-get remove --purge resolvconf
and restarting Network Manager. The only drawback is that it also removes ubuntu-minimal.
Now
Code:
dig askubuntu.com
always work and the system is using OpenDNS in each call.
I can't believe the developers didn't test the name resolution properly before releasing a 12.04 LTS.
Anyway, I'm willing to try other solutions, but in the meantime this is the only way my computer works.
I hope this is useful for someone else.
Cheers!