We have just implemented new Exchange 2007 running on Windows Server 2003.
The problem we are seeing comes from Kodak Insite softproofing system that generates emails from within our LAN. The system is using Windows 2000 Server as OS platform and is using the built in SMTP Virtual Server to send its email, using firstname.lastname@example.org, to our Exchange server fro relay. Emails from hgiproofit arrive ok to our internal mailboxes, but email to the internet gets bounced "Your message wasn't delivered because of security policies." The Windows 2000 server log shows event id 4001. On the Exchange server we do have a hub transport receive connector allowing anonymous connection from the Windows 2000 ip address.