Per flow load balancing

[Corey Smith]

Is there a way to do per flow load balancing using ipfw?

I'm currently using a rule like:

prob 0.5 fwd <tun1gw> ip from any to any recv bge0 xmit tun0

This effectively gives me per packet load balancing between the two
tunnels.  Unfortunately it also leads to significant out-of-order TCP
delivery (the two tunnels have varying latency).

What I'm looking for is the ability to make each TCP socket stick to a
random load balanced tunnel interface for its entire lifetime IE route
multipath.

-Corey Smith