[ILUG] Routing.

[Nick Murtagh]

On Tuesday 15 January 2002 18:26, Mark Kilmartin wrote:
> I believe the NATing is working just the replies are going to the wrong
> interface.

There are two types of NAT. Destination NAT and source NAT. You have got 
a working destination NAT. I suggested adding source NAT so that packets
heading to the server appear to come from the interface on the firewall
on which they arrived. Hence the server will send its reply back to
that interface.

eg

    a.b.c.x (ISP 2)      packet appears to come from some routable 
       |                 internet address
       |                     |
       |                    \|/
    10.1.1.2 (firewall)  SNAT here, now packet appears to come 
       |                 from 10.1.1.2
       |                     |
       |                    \|/
     server              server receives packet, sends reply to
                         10.1.1.2

I think this should work.