So i have a single BSD firewall using NATD and IPFW. This firewall has 5 static IP's assigned to it.
Using NATD i can easily forward and entire external ip to an internal ip. But when the internal server sends it's response how do i get it to come out of the correct IP? NATD just uses the firewalls default gateway.
NATD will only listen on one interface, so it cannot work both directions. It will only forward traffic from external IP's to internal IP's. I need to ensure that all outgoing traffic from a specific internal IP address goes of a specific external IP address.