route del default gw 192.168.85.254 #Get rid of the local network routing table and change it to manual addition
route add -net 192.168.85.0 netmask 255.255.255.0 gw 192.168.85.254
route add -net 192.168.100.0 netmask 255.255.255.0 gw 192.168.85.254
route add -net 172.169.101.0 netmask 255.255.255.0 gw 192.168.85.254
refer to
http://linux-ip.net/html/tools-route.html#ex-tools-route-add-http://linux-ip.net/html/tools-route.html#ex-tools-route-add-net