[ILUG] Routing.

[Mark Kilmartin]

OK I tried this and using tcpdump I can see that the source NATing and
Destination NATing are now both working.


But using tcpdump on the firewall I can see that packets are still
trying to return through the wrong interface.

MArk



On Tue, 2002-01-15 at 19:14, Nick Murtagh wrote:
> 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.
> 
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