I was setting up the IP Allow List Properties on a SBS2008 box with exchange 2007 under the hub transport Windows SBS internet receive connector. I added the approved addresses for the prespam filter and restarted the service. The strange thing is if I do not have the routers LAN address in the approved list emails do not flow to the server. In the past I have only had to add the external addresses. Does anyone have an idea why I need the routers lan address needs to be in the list? The router is setup with a simple port forward on port 25 to the server.