Hello. We have completed migrating our first five mailboxes from Exchange 2003 to Exchange 2010. When an Exch2010 user sends an email that includes both Exch2010 and Exch2003 recipients, the Exch2010 recipient gets duplicate emails. The first email the recipient gets comes directly from the Exch 2010 server and the second one arrives one minute later from the old Exch 2003 server. The two message that the Exch2010 recipient gets have different message IDs. It looks to me like the old Exhcnage 2003 server is receiveng the original message from Exchange 2010 server and then delivering a new copy of the same message to the Exchnge 2010 server. As far as connectors go, in the original Exhcange 2003 environment we have one defined Connector that routes all outbound mail (*) to a SmartHost -- a gateway appliance in our DMZ. We have the default Exch2003 SMTP Virtual Server configured to receive inbound mail for domain. In the Exchange 2010 we have only the default Receive connector, and one Send Connector -- the above-mentioned Exchange 2003 inherited outbound conenctor to our gateway appliance. Email is working OK internally and externally on both servers in every other way. Can anyone help me figure out why these duplicate messages are being forwarded from Exchange 2003 to our Excahnge 2010 users with a different message ID? Below are headers from duplicated messages. Thanks in advance. First received message header ------------------------------ Received: from exchange2010.company.net ([fe80::357c:ae4d:28d:63c9]) by exchange2010.company.net ([fe80::357c:ae4d:28d:63c9%11]) with mapi; Thu, 15 Jul 2010 13:16:15 -0600 Content-Type: application/ms-tnef; name="winmail.dat" Content-Transfer-Encoding: binary From: "Doe, John" <doej@company.net> To: TestExch2 <testexch2@company.org>, TestExch2 <testexch2@company.org>, "Doe, John" <doej@company.org> Subject: Dup test 1 Thread-Topic: Dup test 1 Thread-Index: AcskUi+aIqRdn/WTQKadEj6oktGBMA== Date: Thu, 15 Jul 2010 13:16:11 -0600 Message-ID: <E45294D562977142931E5462BD13FCBC14DF7EAC@exchange2010.company.net> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-Exchange-Organization-SCL: -1 X-MS-TNEF-Correlator: <E45294D562977142931E5462BD13FCBC14DF7EAC@exchange2010.company.net> MIME-Version: 1.0 X-MS-Exchange-Organization-AuthSource: exchange2010.company.net X-MS-Exchange-Organization-AuthAs: Internal X-MS-Exchange-Organization-AuthMechanism: 04 Duplicate message header ---------------------------------- Received: from exchange2003.company.org (192.168.200.214) by exchange2010.company.net (192.168.200.7) with Microsoft SMTP Server id 14.0.694.0; Thu, 15 Jul 2010 13:16:16 -0600 Received: from mail pickup service by exchange2003.company.org with Microsoft SMTPSVC; Thu, 15 Jul 2010 13:16:15 -0600 Message-ID: <E5AE117DC60D44EB827721D88A6574DC@company.net> X-MimeOLE: Produced By Microsoft MimeOLE V6.00.3790.4657 Content-Transfer-Encoding: 7bit X-Mailer: Microsoft CDO for Exchange 2000 Importance: normal Priority: normal MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01CB2452.31B42980" Content-Language: en-US Return-Path: <doej@company.org> X-OriginalArrivalTime: 15 Jul 2010 19:16:15.0379 (UTC) FILETIME=[31EDFE30:01CB2452] Accept-Language: en-US Content-Class: urn:content-classes:message Subject: Dup test 1 Date: Thu, 15 Jul 2010 13:16:15 -0600 X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Dup test 1 thread-index: AcskUi+aIqRdn/WTQKadEj6oktGBMA== From: "Doe, Jonh" <doej@company.org> To: TestExch2 <testexch2@company.org>, TestExch2 <testexch2@company.org>, "Doe, Jonh" <doej@company.org> X-MS-Exchange-Organization-AuthSource: exchange2010.company.net X-MS-Exchange-Organization-AuthAs: Internal X-MS-Exchange-Organization-AuthMechanism: 0b

FYI, I'd like to add that I've looked at obvious Rules, additional accounts in a profile, etc.. This is a spedicifc problem that occrs fron anty email client -- Outlook/OutlookApp/Entourage/OA. It occurs ONLY when an Exch2010 users send to BOTH Exch2010 recipients AND Exhc2003 recipients in the same message. The Exch2010 recipient gets the duplicates. Thanks in advance for any help.

Hi EdwinR, I would check the tracking log to analyze the duplicate email tracing. And I would analyze the pipeline tracing log to confirm whether there is some rule cause it. If you have more information, please post here, we could do more research about it. Does the issue occur all the user account on the exchange 2010, is there some thing rule on the exchange 2003 servr or the client endpoint? Some information for you: http://technet.microsoft.com/en-us/library/aa997984.aspx http://technet.microsoft.com/en-us/library/bb125198(EXCHG.80).aspx And it is recommended upgarde the trasport as below when you do the migration. http://technet.microsoft.com/en-us/library/dd638103.aspx Regards! Gavin

We have the exact same problem. When a mail box user on the Exchange 2010 server sends an email to someone on the 2003 server then all the CC users that are on the Exchange 2010 server get 2 emails, the original message from the Exchange 2010 server and a second one (with a different message number) from the Exchange 2003 server. The Exchange 2010 users find it very annoying that apparently the Exchange 2003 server doesn't "know" the message was already deliverd and it should not send the email to the 2010 server recipients. How do we stop this?

On Mon, 2 Aug 2010 20:33:20 +0000, Vic Belebczuk wrote: >We have the exact same problem. When a mail box user on the Exchange 2010 server sends an email to someone on the 2003 server then all the CC users that are on the Exchange 2010 server get 2 emails, the original message from the Exchange 2010 server and a second one (with a different message number) from the Exchange 2003 server. The Exchange 2010 users find it very annoying that apparently the Exchange 2003 server doesn't "know" the message was already deliverd and it should not send the email to the 2010 server recipients. How do we stop this? Are both servers in the same Exchange organization? If they aren't, on the Exchange 2003 server check the set of recipients to which the message was sent. Is the DL in the list? If it is then the E2K3 server is expanding the DL again. If this is the problem it likely that you have something being synchronized between the two directories that shouldn't be. --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

Hi, we have a slightly different problem. When a user sends a message to multiple users on one Exchange 2010 and one Exchange 2003 generates two messages. A message is addressed to users with 2010 and contains all the names in to and cc, and another sent to 2003 email users without the 2010 users present in to or cc field. Any suggestion? Thanks a lotLuca Pozzoli