Question : Exchange 2003 Unresolved Recipients

We reinstalled SBS 2003 and got Exchange Server installed and running prior to having users defined.  This was our mistake, because we should have not re-enabled external email on port 25 until we had users defined.  So we seem to be missing email from the "dark period" when we were offline.

We use a 3rd-party email filtering service, and they recognized the inability to deliver email when we took down the server.  They queued messages.  Then they show successful delivery of the queued messages at a time when we did have the server back up, but no users defined.  Their logs show successful delivery to the Exchange server.

My theory is that Exchange accepted the email, but couldn't resolve what user mailboxes to route it to, so it couldn't deliver it.

My questions:
1) Does my theory make sense?
2) What does Exchange 2003 typically do with email for unresolved recipients?  Does it re-process at a later time?  Does it hold this email somewhere?  Hoping it doesn't just delete it...
3) What are my options now that we have bonafide recipients available?  Can I direct the exchange server to re-process any undeliverable mail?  Can I access the mail and manually route it?  NOTE:  All new mail is resolving and coming through fine - just trying to handle email delivered between the time when Exchange was active again, but no users defined.  Unfortunately, a whole day's worth of email was delivered during this window from our 3rd-party email spam filter provider.

Thanks for any help/insight you can offer!

Best,
Peter

Answer : Exchange 2003 Unresolved Recipients

Yes, your theory makes sense. However, chances are you have lost your email. If recipient filtering was working correctly, Exchange would have immediately rejected the email on the grounds the [email protected] did not exist. If it wasn't working, it would have bounced with a non-delivery report fairly quickly after accepting the email. The onus is then on the sender to retransmit the message if they wish.

If there is any email on the server, it'll be in Exchange System Manager > Servers > your server > Queues. I somewhat doubt you'll find anything there though; Exchange should have rejected or bounded the email immediately on receipt.

>> Can I direct the exchange server to re-process any undeliverable mail?

If it has bounced it, no, the mail has gone and will be lost forever. Email is fairly resilient and had your server not been accessible on port 25, properly configured sending MTAs would have waited 2 days or more before timing out and returning the email to the sender. Since your server was actually online and actively rejecting email, it will be long gone by now.

-Matt