I've recently implemented a hosted spam & virus filtering solution. My MX record directs all email through this filter which then forwards the email to my exchange server. I've noticed that some email gets through the filter by somehow sending the mail directly through to my IP address and bypassing the filter. I was advised by their tech support to restrict all incoming email so that only mail coming from their two IP ranges would be accepted. How do I configure this in my exchange server?
I am running exchange 2k3 on windows 2k3.