A few months ago we migrated to exchange 2007. All was well, but shortly after our Postmaster account started getting flooded with more SPAM than usually, a lot more. I set up Postini for the postmaster account which was never necessary in exchange 2003, so something changed. I did setup Directory Harvest protection via tar pitting (aka Recipient filtering, unsure if its related). Now I'm protected for the SPAM from the Internet, but I no longer receive LEGIT postmaster emails in the postmaster inbox (i.e. Internal users typing wrong addresses and bouncing)
Where should I look to resolve this?