auto eth2
iface eth2 inet static
address 172.17.21.150
netmask 255.255.255.0
dns-nameserver 8.8.8.8 80.80.80.80
post-up route add -net 172.17.22.0 netmask 255.255.255.0 gw 172.17.21.12
post-up route add -net 172.17.23.0 netmask 255.255.255.0 gw 172.17.21.12