# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet static
address 192.168.1.1
netmask 255.255.255.0
gateway 192.168.1.20

auto eth1
iface eth1 inet static
address 192.168.1.3
netmask 255.255.255.0