Situation:
A new client of mine was hacked this weekend. Now their Exchange server is listening and responding to requests on port 1241.

Need:
I need to lock down this port so that is denies all requests. I want to do this from the Exchange server.

Does anyone know any tools or commands to lock down a specific port on a Win2000 machine?

Note: Nessus is not running on the server, and there are no unknown services running.