Can I redirect internal originated traffic to another gateway with netfilter?

[Patrick LEE]

Hi all

I have two netfilter gateways, one connected to  boardband (~256Kbps =
uplink)  and the other to  a leased line  (64Kbps ), both with NAT enabled =
to my private LAN.  And I have an email server behind these firewalls.  To =
be  able to receive mail I have to set the default route of my mail server =
to point to the leased line (fixed IP to  the world) so other can lookup =
it.  What I would like is to direct the internal generated (email i.e. =
SMTP) session to from the leased line gateway to the boardband gateway as =
it has more bandwidth.  I beleive I can detect the newly generated tcp =
session with the syn flag.  What I don't know is if I be able to redirect =
the whole packet and following packet of the same session to the boardband =
gateway? =20

Any comments welcome

Thanks in advance

Patrick Lee