ifconfig eth3 up ifconfig eth3 0.0.0.0 ifconfig eth3 192.168.8.100 192.168.8.255 255.255.255.0 ip route add 192.168.8.0/24 dev eth3 src 192.168.8.100 table wan1 ip route add 192.168.8.0/24 dev eth3 ip route del default dev eth3 table wan1 ip route del default dev eth3 ip route add default via 192.168.8.1 dev eth3 metric 0 table wan1 ip rule add from 192.168.8.100/32 table wan1 ip rule add to 192.168.8.100/32 table wan1 iptables -t nat -A POSTROUTING -o eth3 -j MASQUERADE