Multiple Routing Tables (FIB) + IPFW problem as (I?) expected

[Luiz Otavio O Souza]

>> obviously you did some other commands here..
>> something generated 2 million packets..
>
> Julian, its a production enviroment, firewall was up for a few
> minutes. Thats the reason.
>
>> I was thinking of adding a 'reroute' ipfw keyword.. kind of like
>> 'fwd {original dest} ip from any to any'
>> because 'fwd' does cause the routing decision to be redone.
>>
>> The fib of the process that opens the socket controls where packets from 
>> the
>> local machine are sent.
>
> divert does cause this too, not "not fib X" seems to work fine...
>
> I wish you could make the "setfib" action be kept in state with
> keep-state only for the static rules, but I guess it will be done for
> all dynamic rules too, since keep-state makes dynamic rules repeat the
> static one, right?
>
> would something like
>
> ipfw add prob 0.5 setfib 1 all from X to any out keep-state
>
> be used to balance (per session) between FIB tables?

divert ? i think you want to say natd...

Again... you are using setfib after the route table decisions...

To use natd with setfib you need to setup two instances of natd, one for 
each uplink interface:

ipfw add divert 8668 all from any to any via ${outnic1}
ipfw add divert 8669 all from any to any via ${outnic2}

And on internal nic:

ipfw add setfib 1 tcp from ${inet} to any 80 IN VIA ${iif}

So the http traffic will be routed thru fib 1 and should appear on correct 
uplink interface, and natd can do his the dirty work.

I don't known about prob... you will need to send the connection setup 
packets (for tcp) and subsequent packets through the same link. i don't know 
if you can achive this with prob + keep-state.

Luiz