vaheeD khoshnouD

/etc/network/interfaces

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
  address 172.16.20.110
  netmask 255.255.255.0
  gateway 172.16.20.2

/etc/resolv.conf

nameserver 172.16.20.100

Service Restart

/etc/init.d/networking restart