Hello all, I am running Exchange 2003 with all updates, no smarthost, just direct sending. I am having a strange issue where 1 of my users who sends out PDFs regularly to various recipients. The recipients have been complaining about receiving the email 2-3 times. This doesn't seem to be happening to all recipients, just a few, but it causing problems. I have tried sending with Symantec AV and Mail Security disabled, but duplicates still occur. When it does occur I can see from within Exchange System Manager > Queues that the message status alternates between ready and retry a few times when the user sends out the emails with PDF attachments. It almost seems like the recipients mail server is requesting a retry and so my exchange server retries and each time it does so, a duplicate is then created in the recipient mailbox. I need to be able to show this for certain however, before I can confidently say it is the remote end causing the issue. From within ESM > Message Tracking Center I can see that the email is duplicate from within exchange. Each message has the same timestamp, but the ID's are all unique. One thing that through me off was it happened internally on a recent occasion and without attachment on another, so I am having a hard time identifying a pattern. The one consistency seems to be the Sending user. I checked the users outlook client to see if there were any strange rules or delegation assigned, but there are none of either. No duplicate email shows up in the Sent Items either. The user also recently received a new computer, freshly built with standard installed apps, nothing at all out of the ordinary. I am at a stopping point right now as I am not sure where to go from here, I have run out of troubleshooting ideas. Your assistance is greatly appreciated.

Enable debug SMTP protocol logging and look at the message transmissions. It could be that the receiving server is ending the connection but your MTA is not seeing it for some reason (e.g. your cisco firewall has the SMTP fixup protocol enabled).

The ASA in front of my mail server has fixup esmtp disabled. I just set logging levels to debug, restarted exchange services, and then had my user send to a known duplicate recipient (external to the org) and you know the rest of the story... no duplicate for the first time in a while, go figure right... I am not convinced the issue is resolved though, but worse yet, I still don't even know what causes it. For the moment I will leave the logging level at debug on SMTP so that when I hear another complaint I can have the detail available. Is it only in the event viewer that the debug levels manifest themselves? The system32/Logs didn't seem to have any more detail then they normally do. Anything else anyone can think of to try to nail this down?

The ASA in front of my mail server has fixup esmtp disabled. Likely it's because your server isn't receiving an ack to it's <CRLF>.<CRLF> to end the mail message to indicate the message was successfully received. The duplicate messages have new received headers for the recipients right? That's the most likely explination. Logs will be in the IIS/SMTP directory I believe... keep an eye on them they can grow pretty quickly (not insanely but still).

I am actually having a hard time with headers. All of the duplicates I have been forwarded all have blank headers. I also had duplicates occur internally this morning and those headers are also blank. Is outlook stripping them?

On Thu, 7 Oct 2010 17:39:52 +0000, CipherMan wrote: > > >I am actually having a hard time with headers. All of the duplicates I have been forwarded all have blank headers. I also had duplicates occur internally this morning and those headers are also blank. Is outlook stripping them? It is if the messages aren't forwarded as attachments (or sent as an attachment in a new message). --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP