Configuring DNS in Ubuntu 15.04 (IPv4 and IPv6)

Guide provided because of various bugs with NetworkManager in Ubuntu-gnome 15.04. If you aren't affected by any bug, use GUI for configuring

First of all, you'll need to disable Auto-DNS option for IPv4 and IPv6 in NetworkManager

Then:

sudo nano /etc/resolvconf/resolv.conf.d/head

Provide your DNS servers here (note: IPv6 servers first)

nameserver 2001:4860:4860::8888
nameserver 8.8.8.8

Regenerate config

sudo resolvconf -u

You can check, that nameservers appeared in /etc/resolv.conf

Don't forget to restart your internet connection

You can test IPv6 DNS working / DNS leaks