Having DNS Issues when connected to a VPN in Ubuntu 13.04

First make sure that there are no lines beginning with nameserver in any files in /etc/resolvconf/resolv.conf.d. If /etc/resolvconf/resolv.conf.d/tail is a symbolic link to target original, make it point to /dev/null.

Second, disconnect from the VPN. Edit /etc/NetworkManager/NetworkManager.conf

$ sudo gedit /etc/NetworkManager/NetworkManager.conf

and comment out

dns=dnsmasq

(i.e., add a # so that it looks like the following)

#dns=dnsmasq

and then

sudo restart network-manager

Try checking if your /etc/resolv.conf have symbolic link to /run/resolvconf/resolv.conf . It solved the problem for me.

To check if it has symbolic link:

ls -la /etc/resolv.conf

Sample output, if it has symbolic link:

lrwxrwxrwx 1 root root 27 Jun 30 22:22 resolv.conf -> /run/resolvconf/resolv.conf

Otherwise, delete or backup existing /etc/resolv.conf and then:

sudo ln -s /run/resolvconf/resolv.conf /etc/resolv.conf