>     He has 3 networks cards, one to the internal network, another to an
> ADSL router and the third to a leased line internet link.
>
>     He needs to NAT the internal network, being able to choose which IPs
> go "nated" for the ADSL or for the leased line. Someone suggested he
> should try BGP with Zebra. Does this sound possible ? What about the NAT
> rules ?

Except that with BGP, you'll need to peer up with a BGP peer at the end of
the ADSL circuit and at the end of leased line so your BGP daemon can
learn routing tables.  While that may not be a problem with the leased
line provider, your ADSL provider will most likely look at you like you've
got 12 heads and not have a clue what you're talking about.

An associate of mine has much the same situation, but with a cable modem
and an SDSL circuit...default route is over the DSL circuit, but he's got
lots of static routes for sites he wants to hit over the cable modem.