Within the next week or so, I'll be setting up an AT&T U-verse modem with 5 usable static public IP addresses. I plan to register a domain name pointing at 1 of the 5 static IPs, and run a website from a single server setup in my home LAN.
I'll skip the long winded reason why, but I need to somehow source route outbound traffic (originating from my server) destined for one public domain (i.e. http://www.sample.org) to be from one of the other 4 static IPs only. Basically, I want this public domain to see connections coming from an IP address and not my domain name. If it makes it easier, this can apply to all outbound traffic from my server as long as it doesn't impact users browsing my website! Inbound connections should go through the domain name / registered public IP.
Can I accomplish this with my single server with one or multiple NICs? Do I need multiple servers and set one up as a proxy? Please help as my background is in software and not networking, and I don't think I can accomplish this at the application layer.
EDIT + ADDITIONAL INFO:
AT&T couldn't tell me the model number of the modem+router, sigh, so I'm trying to get a grasp on this before the equipment arrives. My server will be setup behind the modem+router, not directly connected to the internet, with port forwarding setup on my router to fwd traffic from mywebsite.com. I just want all traffic that ORIGINATES from my server internally to go "out" through 1 of the 4 IP addresses NOT registered to my domain. All inbound traffic from mywebsite.com should reply through the 1 domain registered IP.
I've been mulling over this for hours and have an idea: If I have 2 NICs on the internal server and set them up on separate subnets, can I just setup port forwarding from my website to NIC #1 and add a route to my server to have NIC #2 be the preferred route for all outbound traffic? If I understand this correctly, just b/c NIC #2 has a preferred route, it shouldn't interrupt inbound traffic on NIC #1 on a different subnet... correct? i.e. the inbound traffic headed to NIC #1 won't be replied to on NIC #2, right?