We are having an issue with SMTP email timing out between two domains. The other site is a subsidiary company with their own domain. We have been sending e-mail to this domain for many months with no issues. Over the past few days, it seems that any e-mail with attachments will not complete the SMTP transfer. Both sites are using Exchange 2003. We see the SMTP connections being made in the smtp logs in both servers. On the Exchange server on the receiving end we see the connections under current sessions that stay active until they reach the time out limit (we have increased the limit from 10 to 20 minutes, which has not helped). We can also see the e-mail in the Mailroot\VS1\Queue folder of the receiving server that is in the process of being sent. However, most of the e-mails that are in the process of being received never show a size larger than 64kb in the queue folder. We can open these and view them in Outlook Express, and they are indeed the e-mails that are not being received. We have tried several things, like clearing the queues and trying to resend. When we clear the queues, it seems that messages that only have one attachment or a few small ones will be sent. However, once one gets stuck anything with an attachment will not be sent. However, e-mail without attachments are sent and received without any problem. We have stopped and started the SMTP Service on both servers. We restarted the Exchange box on the receiving site. Nothing has worked. We have no problems sending e-mail with attachments to any other domain. Can anyone assist me with any ideas of where to begin trouble shooting this, or any tools that may be available to assist us. Thank you in advance.Exile_Ken

Dear customer: Please help confirm the following information: 1. Did you receive NDR, please post the complete NDR into the forum if you received NDR? 2. On your own Exchange server and all Exchange servers which e-mail will go through, check whether you enable size limit on SMTP connector or SMTP virtual server? 3. On the destination Exchange server and all Exchange servers which e-mail will go through, check you enable size limit on SMTP connector or SMTP virtual server? 4. On your Exchange server, install Network Monitor (Netmon.exe) to capture network traffic between your Exchange server and your subsidiary companys Exchange server, reproduce the issue and stop capture and send the package to v-rocwan@microsoft.com for analyze.Network Monitor is included with Windows 2000 Server and Windows Server 2003. 5. Enable message tracking on your Exchange server, reproduce the issue and open message tracking center, input the sender and recipient click find now, send the result to me for analyze. For more information about how to enable message tracking, please refer to the following article: XADM: Using the Message Tracking Center to Track a Message http://support.microsoft.com/kb/262162/en-us 6. Run Exchange Troubleshooting Analyzer (ExTRA) and select the Mail Flow Troubleshooter to troubleshoot Mailflow and transport-related problems. http://www.microsoft.com/downloads/details.aspx?familyid=4BDC1D6B-DE34-4F1C-AEBA-FED1256CAF9A&displaylang=en 7. Set all categories under MSExchangeTransport to maximum, and reproduce the issue and check the application log. How to troubleshoot for Exchange Server 2003 transport issues http://support.microsoft.com/?id=821910 note: when you send e-mail to me, please let me know the subject of the post. Hope it helps. Rock Wang - MSFT

Was there a resolution to this problem? We are experiencing the same issues on incomming emails with larger (3 or more MB) attachments.