DNS resolution fails after 12.10 upgrade
Change 127.0.0.1 to 127.0.1.1 in /etc/resolv.conf
Looks like this is a known issue:
Launchpad bug#1051348
The instructions there worked for me
In a terminal, run
sudo apt-get install resolvconf # in case it got removed
sudo dpkg-reconfigure resolvconf # to restore the symlink at /etc/resolv.conf
then reboot.