You’ve seen it before. A user leaves your company, you delete or purge their mailbox, and they decide they want to come back to their old job. So, you create a new AD account and mailbox for them.
Problem is: some of their old coworkers still have old messages from them before they left, and when they reply to those messages they think it’s gonna go to their new mailbox. Only they’re confused when they get the following NDR:
Your message did not reach some or all of the intended recipients.
Subject: RE: Old conversation
Sent: 9/30/2008 8:22 PM
The following recipient(s) cannot be reached:
Blow, Joe on 9/30/2008 8:22 PM
The e-mail account does not exist at the organization this message was sent to. Check the e-mail address, or contact the recipient directly to find out the correct address.
This is because the old message contains the legacyExchangeDN as the return address. You created a new mailbox so there’s a new legacyExchangeDN for that same person. How do you fix this so that users can reply to old messages and have those replies get delivered to the new mailbox?
Add a new E-mail address to the AD object for the returning user in the format of:
Set the E-mail type to be X500
See http://support.microsoft.com/kb/313324 for more info