I can think of two ways to do what you want, off the top of my head:
- One, use a bridging firewall (firewall with no IP address)
DSL --- [bridging FW] --- DMZ (allocate IPs as you see fit here)
- Two, assign all five addresses to your firewall machine,
and use some kind of static NAT assignment. (Sorry, I don't know the
Linux terminology here, I come from a BSD world).
In other words, configure address translation (masquerading)
to route everyting addressed to IP#1 to the machine 10.1.1.2,
everything addressed to IP#2 to 10.1.1.3, and so forth.
On platfoms running PF or IPF, this is a referred to as a BINAT.
Hope that helps...
