# vim /etc/network/interfaces
auto eth0
iface eth0 inet dhcp
   post-up ip route add default via 172.16.100.1 dev eth0 tab 1
   post-up ip rule add from 172.16.100.99 tab 1
   pre-down ip rule del from 172.16.100.99 tab 1
   pre-down ip route del default via 172.16.100.1 dev eth0 tab 1

auto eth1
iface eth1 inet dhcp
   post-up ip route add default via 172.16.111.1 dev eth1 tab 2
   post-up ip rule add from 172.16.111.169 tab 2
   pre-down ip rule del from 172.16.111.169 tab 2
   pre-down ip route del default via 172.16.111.1 dev eth1 tab 2