Exchange 2007, W2k3 x64. 25 mailboxes, SMTP, various OUtlook clients (2003/2007OWA) We have a case where when you send to Exchange users via SMTP addresses, the exchange box translates them to a different SMTP address. When I send to: JDOE@MYDOMAIN.COM it translates it to: JOHNDOE@MYDOMAIN.COM what's weird: The primary SMTP address for all Exchange 2007 is first initial/lastname@mydomain.com I'm standing besides myself trying to figure this one out. basically, messages are getting reported as undeliverable. Error reported: Delivery has failed to these recipients or distribution lists: JOHN DOEThis recipient e-mail address was not found in the recipient e-mail system. Microsoft Exchange will not try to redeliver this message for you. Please check the recipient e-mail address and try resending this message, or provide the following diagnostic text to your system administrator.

Hi, Have you tried message tracking for one of these messages? Are these internal messages or from the outside? Any smtp scanner between your exchange server and the internet? Leif