Hi Vijin, As we know, the email would be delivered according to the email address of the mailbox, if there are two mailbox have the same address, how the email will be delivered. So, that is by design. :) Some information for you: http://blogs.technet.com/b/exchange/archive/2005/01/10/350132.aspx Regards! Gavin TechNet Subscriber Supportin forum If you have any feedback on our support, please contact tngfb@microsoft.com Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Hi Gavin - I'm not talking about mailboxes.... I'm talking about "Contacts" and "Mail-Enabled users" Vojin

I need confirmation that duplicate email addresses are not supported in Exchange. I know it is not supported in any version of Exchange server, but I need "proof" - link. Thanks, Vojin

You can reference the doc below, you probably won't find a doc that will explicitly say "not supported' it's inherently implied. Removing duplicate and unwanted proxy addresses in Exchange http://support.microsoft.com/kb/318774James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

Hi Vojin, For mailcontact as the mail-enabled users, the internal email address would be created by the EAP, and the proxy address must be unique. It is by design, please refert to below: http://technet.microsoft.com/en-us/library/aa125371(EXCHG.65).aspx Regards! Gavin TechNet Subscriber Supportin forum If you have any feedback on our support, please contacttngfb@microsoft.com Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Hello, Any update for your issue? ============= Simon Wu Exchange Forum Support Please remember to mark the replies as answers if they help and unmark them if they provide no help. If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.