How do I set the dns search domain in Ubuntu 12.04?

Solution 1:

Since you seem to be using resolvconf, you will want to use the dns-search option within your network interfaces file

#/etc/network/interfaces 
# The primary network interface
auto eth0
iface eth0 inet static
    address 10.2.37.4
    netmask 255.255.254.0
    gateway 10.2.37.1
    dns-nameservers 10.2.51.4 10.2.52.4
    dns-search example.org