I had some trouble getting the static ip configuration right for Ubuntu 12.04 Server. Every time I would restart the server the nameserver settings in
/etc/resolv.conf would get overwritten by dhcp client. Many tutorials suggest doing an apt-get remove for dhcp-client but this didn't work for me either.
I found this page that documents how to do this in 12.04.
You basically need to add your nameserver settings in the
/etc/network/interfaces file like so:
iface eth0 inet static address xx.xx.xx.xx netmask xx.xx.xx.xx network xx.xx.xx.xx broadcast xx.xx.xx.xx gateway xx.xx.xx.xx dns-nameservers xx.xx.xx.xx xx.xx.xx.xx
Note that dns-nameservers is where you add your DNS nameservers (they didn't get creative with the name, heh!)