sudo nano /etc/network/interfaces
add the following at the bottom of the file
auto lo:1 iface lo:1 inet static address 127.0.0.2 netmask 255.0.0.0 #network 127.0.0.0
then
sudo /etc/init.d/networking restart
References :
http://serverfault.com/questions/579435/arbitrary-loopback-ip-addresses-besides-127-0-0-1