I am looking to block my Exchange 2000 server from receiving email from anyone except for a specific IP range. The problem is that I am receiving a ton of spam that apparently is coming to the server by IP address rather than by MX record. My MX record actually points to a hosted spam filter and looking at the headres, the emails are not coming from the spam filter host. I want to restrict my Exchange 2000 server from accepting email from anyone but my spam filter host. Anyone know how to do this?