Re: NATing on a single interface?

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Robert Nichols wrote:
There's no reason a forwarded packet can't go back out the same
interface on which it arrived.  There's an obvious compromise in
security when you have both sides of the firewall on the same

I do trust my own machines, basically because they're mine - I'm very obsessive about keeping the OS and virus scanners up to date.

> physical network, but if you trust your own machines and just
> want to protect against external attacks you should be OK as
> long as the DSL router forwards packets to the firewall machine
> only.

It appears to be mangling the packets - e.g. an inbound packet from 12.34.56.78 to 98.76.54.32 (PPP_IP) gets its destination IP changed to the DMZ address (e.g. 10.0.0.1 for my server). Return packets are sent to the source (e.g. 12.34.56.78 in the example) using the DSL router (10.1.0.2) as the gateway.

What I need to figure out is how to actually set up the firewall. I did find a nice IPTables tutorial, but it's 357 pages long! Guess I'd better stop procrastinating and start reading....

Thanks.
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