Hi Mike,
I have several questions that can be used to start narrowing down the problem and find a solution.
First, what do the logs on the exchange server say?
- Are you really sending multiple copies or making multiple attempts to send e-mails?
- Is a problem causing exchange to think mails are not sent successfully causing it to retry?
If you are sending multiple messages is there something on your users workstations causing duplicates? For example, do they have a McAfee or Norton (any AV scanner) on their workstation that is scanning outgoing e-mail and causing the local e-mail client to send duplicate e-mails into your exchange server? Anything else that is or would resemble a "stuck outbox" problem? Less likely, do any of your users have address books that map a contact to duplicate addresses?
If you are making multiple attempts at outbound connections is there anything in your network that could be causing the problem?
- A pix firewall that needs no fixup protocol smtp 25 enabled?
- An Anti-spam or Anti-Virus scanner intermittently timing out?
- A proxy server or device in the network causing intermittent dropped connections?
- The remote end dropping the connection early due to improper reverse DNS for the IP/NAT of your exchange server?
Are you able to get the
full e-mail headers from a pair of duplicate messages on the receiving end? If you are, please post both them here so we can help you analyze them if needed. Is there a mail admin on the receiving end who can check their logs and check for the same network issues such as the pix firewall issue mentioned above? Since you mentioned the problem is happening for multiple destinations it sounds like the problem is closer to home for your server than theirs, but it can't hurt to take a few minutes and ask the clients the same questions.
If these questions don't reveal the actual problem it should get us close to the source of the trouble.
-Raymond