Dear All, There is a case which is difficult to figure out. We found that SOMETIMES some emails disappeared during transmission. Case: Internal Source Server (Exchange 2003 with SP2) to Internal Destination Server (Exchange 2003 with SP2) From the Message tracking Centre in the source server, there is a log shown that the message has been sent to destination server. But actually there is no such email received. We have tried to check with SMTP log with the source server. It was found that there is NO any smtp command follow the "BDAT" command, such as --250, QUIT, --221..etc. OutboundConnectionCommand SMTPSVC1 Server1 - 25 BDAT - 33916+LAST 0 0 4 0 1125 SMTP - - - - It seems the connection was disrrupted. Would you please advise anything I can check ? Regards, Tommy

Hi Tommy, Are the two servers in the same exchange ORG, and are they in the same routing group? Or the sender's mailbox and the recipient's mailbox on different exchange servers. Or you could post more smtp log on the two servers here, we could do more research about the issue. Any third party software involves into the message delivery course. Regards! Gavin TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.comPlease remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Hi Tommy, Did you check deleted email in recover deleted items for mailbox to which it was send. Some time due bad rule it gives this kind of issue. Also let me know whether it is happening for all users or for some specific users. Anil MCC 2011,ITIL V3,MCSA 2003,MCTS 2010, My Blog : http://messagingschool.wordpress.com

Hi Tommy, Any update for your issue? Regards! Gavin TechNet Subscriber Supportin forum If you have any feedback on our support, please contact tngfb@microsoft.comPlease remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.