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Re: route selection and ipfw forwarding

> It is possible to do load sharing, but not balancing in the true
> sense of the word. You need to use ipfw's FWD rule to forward (push)
> packets to the different gateways of the 4 WAN links, but it get's a
> bit more complicated from there.

To do this using forwarding to four different gateways is simple enough,
but I'm not sure what results to expect by doing this to the same
gateway over four different links. I know of no way to influence the
decision and I am not sure how the routing algorithm would decide to
handle this situation.

> You now also need to keep-state on each of the sessions, and will
> have to check-state of all established outgoing packets to send them
> out the same WAN link as the rest of that sessions packets.

I understand the importance of source-based routing with respect to
transit, but I'm a bit unclear on how dynamic rules relate to
forwarding. As long as all packets arrive at the destination and are
properly addressed, the host should not care how they got there. I'm not
sure if I know what you mean by session. I can't imagine an IPFW ruleset
that would provide stateful routing.

> It's a dirty solution, but I have a working system with 2 WAN links. 
> You can also use IPFW set's to manage the percentage splits betweeen
> the links. (or for failover).

Would you mind sharing your ipfw ruleset (ipfw list)?