Custom Wood Case for the MultiPlex MiniMag RC Plane »Exchange Event ID 3005 MSExchangeTransport
If you're not an Exchange administrator, skip this one.
I finished up a 1200 user Exchange 2003 to 2003 migration on Jan 31. After catching up on sleep for a few days it was time to turn off the source Exchange servers. Post shutdown, I ran through the eventlog looking for problems and found the MSExchangeTransport Event ID 3005. This is indicative of a mail loop, which can have many root causes. In this case, the loop was for a secondary SMTP domain, brought from the source Exchange server. Once the source servers were offline, checking the "This Exchange Organization is responsible for all mail delivery to this address" button on the e.mail address under the Recipient Policy fixed the problem.
It's a no-brainer of course, but there was a window of an hour between turning off and retiring the old source Exchange system and when I updated RUS. The messages looping caused the SMTP Q's to build up on a few servers which triggered the Q alarms. Below are the pre-fix and post-fix NDR's when sending a test message to a non-existent user, and the eventlog capture of the NDR. Messages to valid users continued routing normally, so only e.mail to invalid users resulted in the loop.
The following recipient(s) could not be reached:
nul.user@myotherdomain.com on 2/3/2007 9:52 PM
A configuration error in the e-mail system caused the message to bounce between two servers or to be forwarded between two recipients. Contact your administrator.
<exchange.server.mydomain.com #4.4.6>
The NDR you do want (undeliverable):
The following recipient(s) could not be reached:
'null.user@myotherdomain.com' on 2/7/2007 10:05 PM
The e-mail account does not exist at the organization this message was sent to. Check the e-mail address, or contact the recipient directly to find out the correct address.
<exchange.server.mydomain.com #5.1.1>
Full Text of the Error message:
Event Type: Error
Event Source: MSExchangeTransport
Event Category: NDR
Event ID: 3005
Date: 2/3/2007
Time: 9:52:04 PM
User: N/A
Computer: MyExchangeServer
Description:
A non-delivery report with a status code of 4.4.6 was generated for recipient rfc822;null.user@myotherdomain.com (Message-ID
Cause: The maximum hop count was exceeded for this message. This non-delivery report can also be caused if a looping condition exists between sending and receiving servers that are not in the same Exchange organization. In this situation, the message bounces back and forth until the hop count is exceeded. A configuration error in the e-mail system can also cause the message to bounce between two servers or to be forwarded between two recipients.
Solution: The maximum hop count is a property set on each virtual server and you can manually override it. The default maximum hop count is 15. Also, check for any situations that might cause loops between servers.
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