I am looking to set up an advanced network. I'd rather not discuss the specifics, but rather tell you what I need. I want to connect my high speed modem directly to my server, which has 2 Ethernet adapters. My server will have a fresh install of either Win 2003 (Prefered) or Win 2008. I want to use it like a router. I am pretty sure it can handle all of the necessary protocols.

I am not sure exactly how it works, but here is what I think it will involve:
NAT pass through
DHCP
DNS
Gateway

I am assuming it will need more than that. I am wondering if I could get more layman info on these, rather than howto's. I think if I could get it to offer these services on one adapter and be able to get it to connect to the internet on the other adapter then the service adapter could be hooked up to a switch and in turn have other computers connect to it. It would use DHCP to allocate the configuration settings, NAT to allocate port settings and forwarding, DNS to resolve host names within the network and intranet domains, and the Gateway to tunnel traffic to the internet.

I would rather have this type of control versus a router because this computer will be part of a larger network and also I need it to offer other services which I am already familiar with.

Also I was wondering if it were possible to use the DNS service in order to handle the internal Domains and point HTTP Domain requests to the proper IP and also to pass all other requested HTTP Domain requests to a public DNS server. Say, 4.2.2.1. Please correct me where ever I am wrong, I am still learning and don't quite understand all of this. I will eventually be working with linux to achieve the same type of scenario.

Thank You in Advance.

It looks to me like you know everything you need, and you just have to set it up. The NAT and Gateway parts, you will find under Routing and Remote Access, which you may need to install from Add/Remove Programs in the control panel. DHCP and DNS can be found in the same place, though you can also find them in the "Configure Your Server" wizard that pops up after you install windows server. From there, it's just configuring those three services, which you can find instructions for on the Microsoft website, and several other sites you can Google for, or you can post back here with specific questions if you need help setting them up.