Routing by source?

A question, don't know if it's possible. Looked in the howto's but didn't
find anything.


Situation

Internet
| |
link A link B
| |
firewall-A firewall-B
192.168.0.1 192.168.1.1
| |
\ /
\ /
| |
eth0 eth1
192.168.0.2 192.168.1.2
webserver



The webserver is configured with both gateways
0.0.0.0 gw 192.168.0.1 metric 0
0.0.0.0 gw 192.168.1.1 metric 1

So normal traffic goes throught link A,
if A goes down, normal traffic goes through link B.


When both links are up, someone from the outside can go directly to eth1
(through link-B), but the respons will return by link-A.
This works for most things (http/pop/ssh etc.)
But passive FTP doesn't work.

In the firewall's the module ip_conntrack_ftp is loaded, so by normal
situation the firewall knows what port to let open. Only in this case the
traffic needed is gone out by the other firewall.
So after the inititial 'handshake' the portnumber is sent to the
internet-client (by the default gateway/firewall-A), and the client opens
this new port to eth1, but this is offcourse blocked by firewall-B


Solution:
If traffic is coming in by eth1, it should go out by eth1 and gateway-B (not
the default gateway)

Is this possible?


or do I need another solution?


BTW.
if the webserver is a windows-server (with WU-FTP) it still works.
Seems as this machine tries also the other connection if the ftp-connection
isn't made.... (or it blast out the request to all it connections by default
:-))



I also had to punch open the firewall for connections to normal ports NOT
syncing and not established already. (same problem)


Hope someone gives me a clue where to look for (or tell me that's
impossible)


best regards,
Pascal

In article <XtA0b.76025$(E-Mail Removed)>,
Pascal Nobus wrote:
> Solution:
> If traffic is coming in by eth1, it should go out by eth1 and gateway-B (not
> the default gateway)
>
> Is this possible?

iproute2. See the Adv-Routing-HOWTO. Also see the Linux dead gateway
detection patch here:
http://www.ssi.bg/~ja/
--
/dev/rob0 - preferred_email=i$((28*28+28))@softhome.net
or put "not-spam" or "/dev/rob0" in Subject header to reply