Hi All, I got a problem with receiving some mail with my Exchange 2003 server. Problem description: When the exchange server receives the email, the authentication work normaly (EHLO...) The exchange server starts receiving the DATA part and disconnect before receiving the final <CRLF>.<CRLF> Transmission log sample: Connection from 65.54.246.146 accepted on xxx.xxx.xxx.xxx:25 220 SRV1.idweaver.com Microsoft ESMTP MAIL Service, Version: 6.0.3790.3959 ready at Thu, 29 Oct 2009 12:33:21 +0100 EHLO bay0-omc2-s51.bay0.hotmail.com 250-SRV1.idweaver.com Hello [xxx.xxx.xxx.xxx] 250-TURN 250-SIZE 250-ETRN 250-PIPELINING 250-DSN 250-ENHANCEDSTATUSCODES 250-8bitmime 250-VRFY 250 OK MAIL FROM:<staff@hotmail.com> 250 2.1.0 staff@hotmail.com....Sender OK RCPT TO:<abuse@emailr.com> 250 2.1.5 abuse@emailr.com DATA 354 Start mail input; end with <CRLF>.<CRLF> From: staff@hotmail.com Subject: complaint about message from 77.241.91.53 To: abuse@emailr.com Incoming mail action: client disconnect/delete Connection from 65.54.246.146 closed SMTP log: xxx.xxx.xxx.xxx, bay0-omc2-s38.bay0.hotmail.com, 29/10/2009, 12:25:52, SMTPSVC1, SRV1, xxx.xxx.xxx.xxx, 0, 35, 216, 250, 0, EHLO, -, bay0-omc2-s38.bay0.hotmail.com, xxx.xxx.xxx.xxx, bay0-omc2-s38.bay0.hotmail.com, 29/10/2009, 12:25:52, SMTPSVC1, SRV1, xxx.xxx.xxx.xxx, 0, 29, 42, 250, 0, MAIL, -, FROM:<staff@hotmail.com>, xxx.xxx.xxx.xxx, bay0-omc2-s38.bay0.hotmail.com, 29/10/2009, 12:25:52, SMTPSVC1, SRV1, xxx.xxx.xxx.xxx, 0, 26, 29, 250, 0, RCPT, -, TO:<abuse@emailr.com>, xxx.xxx.xxx.xxx, bay0-omc2-s38.bay0.hotmail.com, 29/10/2009, 12:25:53, SMTPSVC1, SRV1, xxx.xxx.xxx.xxx, 750, 26, 29, 240, 1234, QUIT, -, bay0-omc2-s38.bay0.hotmail.com, I made thousand of tests from an external IIS/SMTP server to try to isolate the problem. I noticed that the proble occurs when the header of the mail is encoded in UTF-8. If I send axactly the same mail but encode it in "Quoted-Printable", it arrives perfectly. As this problem is now occuring more and more often, from time to time from gmail accounts, quite often from Mac users... it's now a big issue I need to solve. I didn't find any solution on technet. Does anybody can help? Thanks

Is there anything inbetween the outside world and this SMTP server that could be interfering with the packets before they arrive? Do you have any devices designed to scan / check the SMTP traffic or in any way access the SMTP communication? This looks like classic SMTP interference to me. Shaun

I have 2 devices that can be interferencing with the transmission: - The latest NoSpamToday version, but I already deactivated it and the symptoms didn't disapeared. So I guess it's not the cause. - And a Cisco PIX, which I didn't check already. Does anyone had problems with that device? Maxence

It's highly likely to be interference. If the problem is easily reproduced, then it may be worthwhile getting the SMTP on the Edge for a minute or two, run the tests and see if there is any difference. Otherwise, perhaps swap the hardware and see if the problem disappears. Shaun

Thanks. I'll try this and keep you posted...

Hi,Please try to increase the diagnostic logging level for MsExchange Transport to get more informaiton. How to Change Logging Levels for Exchange Processes http://technet.microsoft.com/en-us/library/bb201670.aspxRegards,Xiu

We've changed the Cisco PIX configuration and uncheck the ESMTP traffic monitoring. Every thing is now working normally. Thanks for you help, and I hope this post will be helpfull for others... Best regards.