I work at a public library and I'm trying to configure OCLC's EzProxy software.

I've run into a problem and I think it's related to our network config. I'm punching above my weight here a little so I need some help.

I think I'm trying to configure a 1:1 NAT, but not sure how or if our hardware supports it.

The EzProxy machine is on an internet line which supports multiple external IPs. Our router is a Billion BiGuard30.

There's another server on this line, let's say its IP is x.x.x.9. The EzProxy machine is x.x.x.11

I've set up port forwarding from x.x.x.11 on the http ports to the EzProxy machine.

Trying to browse to x.x.x.11 from an external PC works fine - we get to the EzProxy page we are serving.

However, if we go to something like WhatIsMyIP from the EzProxy machine, it says that its IP is x.x.x.9. This causes problems with our user authentication software.

How do we make the rest of the internet see that the machine is x.x.x.11?

There doesnt seem to be any "outbound port forwarding" on the Billion router, nor is there any "1:1 NAT" options in its config webpage.

The EzProxy machine is running Ubuntu 12.04, if that helps.