I have a block of IP addresses, and a Cisco RV325 Router. I can do NAT from one external IP to an internal IP. I don't know however how to send traffic from an internal IP through to a specific external IP. In other words, I am running port 25 to allow SMTP Traffic, but to also send SMTP traffic. And most of my traffic goes out through one IP that normally wouldn't accept SMTP. But my block of External IP's will. I don't want to set this server up on the outside network, i'd rather keep it NAT'ed and internal.
How can I force traffic from this windows machine through via a specific IP address?