Hello, We have Exchange 2007 configured to relay mesages thru our ISP's smarthost because of limited bandwidth. Since we upgraded from Exchange 2003 to 2007, our ISP has been blocking outgoing OOF messages from our users as spam. The reason is that the format of OOF replies has changed in 2007 and the envelope sender is empty? Is there a way to revert to the previous behaviour in E2K7 please? Or another workaround? Thanks, - Alan.

It is by design to be rfc compliant. I'm not aware of any work arounds and doubt there is, you won't be able to use any transport rules out the box or custom to modify the message headers or envelope since it is a system generated message also. Message Disposition Notification (MDN) messages are defined in RFC 2298. Message Disposition Notification (MDN) messages should be sent with blank sender. This behavior is new in Exchange 2007, as in Exchange 2003 and earlier OOF messages were sent with Sender field populated. For more information: http://rfc.sunsite.dk/rfc/rfc2298.html http://technet.microsoft.com/en-us/library/bb430743(EXCHG.80).aspx For your reference: The envelope sender address (i.e., SMTP MAIL FROM) of the MDN MUST be null (<>), specifying that no Delivery Status Notification messages or other messages indicating successful or unsuccessful delivery are to be sent in response to an MDN. http://social.technet.microsoft.com/forums/en-US/exchangesvrgeneral/thread/2bf53ac6-bba2-4f53-916d-eaaeefd4e5d8/James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

Thanks. Even if it is a system-generated message, do you think I could write an event sink to catch it and insert a fake internal FROM address?

No event sinks in Exchange 207 only transport agents and they won't process system generated messages.James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com