Setting up Win2K Server as a Router

Hi,

I am relatively newbie to the Server2000 and Active Directory and need some help with the following.

I have a client who needs to separate 2 departments. No traffic between the two at all. In fact, both have their own domain controllers. Iam working on one of the domain controllers.

I want to set up my domain controller alone and that is working fine. I now need to connect it to the network and want to separate my network by having the DC act as a router. After much reading though, it is not clear how I set up 2 NIC boards and indicate to them how to operate.

How do I set up one NIC card to only communicate with my domain computers and the other NIC card to communicate with the outside world.

Hope this is clear.

Thanks

Nate