I would like to intelligently route packets in MacOS X. I have a Wifi and Ethernet connection. Ethernet connection is high speed but extremely unreliable for outside connectivity. Wifi is from a mobile device and slow. I cannot make the ethernet connection better as it is out of my hand. If possible I would love some sort of failover packet routing. If main internet connection cannot reach internet (for example a public IP) then it should failover to secondary connection from Wifi. In the case the Ethernet is working fine again it should make the routing from ethernet.
Note that Ethernet connection does not go down, the outside connectivity goes down. Right now as far as Mac is concerned it should route outside packets to Ethernet The network service order does not work in this condition.