I love ExBPA. What is weird is that it does recommend that I set up tarpitting on my SMTP bridgehead servers when I have neither the recipient policy applied on my SMTP virtual servers (that I can see) nor the "Filter recipients who are not in the Directory" option checked. I tried enabling the recipient filter on the virtual servers (click apply) then disabling it (click apply), but that didn't help. I even removed the one address from the recipient filter list that was there but not really being used (that I can tell).
A bigger question that I would ask is this: From a spam standpoint, which is better, setting up tarpitting and rejecting messages for users not in the directory or just accepting everything and then having Exchange [try to] deliver a failure notice to the spammer?
Cheers! Thanks for ExBPA!