^if you have iptables already configured before ,you may like to allow those DNS entries to communicate

else it will stand still.
Code:
iptables -A RH-Lokkit-0-50-INPUT -p udp -m udp -s 208.67.222.222 --sport 53 -d 0/0 -j ACCEPT
iptables -A RH-Lokkit-0-50-INPUT -p udp -m udp -s 208.67.220.220 --sport 53 -d 0/0 -j ACCEPT
^from lokkit entry of ubuntu.