Moved from Exchange 2003 to 2010, now getting SPAM through Postini
This weekend I moved our organizations mailboxes from our old 2003 Exchange over to a 2010 Exchange server and now we are receiving a large amount of SPAM even though mail is being processed by Postini. I have our firewall and the receive connector only accepting connections from the Postini address range. I can't think of how SPAM would be making it in.
What else should I look into? Is there something obvious that I missed?