Destination NAT question

Andrew Pollock andrew.pollock@singtech.com.au
Mon, 10 Dec 2001 17:44:27 +1000


Hi,

I've managed to configure destination NAT as per the Linux 2.4 NAT HOWTO.

I've bound the public IP addresses as secondary interfaces of my NAT box,
and I'm doing DNAT to change external traffic to them to the private IP
addresses that they actually have inside the network.

I'm also doing SNAT for the private IP, redirecting internal traffic to the
NAT box (as per part 10 of the above HOWTO).

It's all working pretty nicely.

The only problem I have is that if the NAT box itself tries to access the
external IP address, because it's bound to a secondary interface on itself,
the connection winds up on the NAT box, instead of being NATed to the
private IP internally. (I hope I explained that clearly enough)

Is there any way to avoid this? I'd like to have consistent DNS inside and
out, so therefore all boxes (inside, outside and the NAT box) will be trying
to talk to the public IP addresses of servers inside the network.

Any help appreciated

Andrew