Catatan agar tidak lupa

In Ubuntu 12.04 the handling of resolv.conf changed.

If you want to add your own nameserver address(es) then edit the file /etc/resolvconf/resolv.conf.d/head

sudo nano /etc/resolvconf/resolv.conf.d/head
and add your nameserver there (eg: Google open dns)

nameserver 8.8.8.8

save the file and then run

sudo resolvconf -u
No reboot or anything else. Maybe you will need to restart network-manager

sudo service network-manager restart
Done.

You can test it with the command

nslookup www.google.com