XFOR: IMC Messages Left in \Imcdata\Out Directory (146795)

SYMPTOMS

When the Microsoft Exchange Internet Mail Connector (IMC) fails to resolve the destination host for a message because the chain of CNAME records is greater that eight records long, the message will not be returned with a Non-Delivery Report (NDR). Instead, it will sit in the \Imcdata\Out subdirectory in retry mode.

MORE INFORMATION

The following is a chain of CNAME records from a sample DNS server:

   cname0of8.test.microsoft.com.   IN CNAME
   cname1of8.test.microsoft.com.
   cname1of8.test.microsoft.com.   IN CNAME
   cname2of8.test.microsoft.com.
   cname2of8.test.microsoft.com.   IN CNAME
   cname3of8.test.microsoft.com.
   cname3of8.test.microsoft.com.   IN CNAME
   cname4of8.test.microsoft.com.
   cname4of8.test.microsoft.com.   IN CNAME
   cname5of8.test.microsoft.com.
   cname5of8.test.microsoft.com.   IN CNAME
   cname6of8.test.microsoft.com.
   cname6of8.test.microsoft.com.   IN CNAME
   cname7of8.test.microsoft.com.
   cname7of8.test.microsoft.com.   IN CNAME
   cname8of8.test.microsoft.com.
   cname8of8.test.microsoft.com.   IN CNAME
   test.microsoft.com.

If you compose a message to user@cname0of8.test.microsoft.com, the message will not be NDR'd. The message will sit in the \Imcdata\Out subdirectory in the retry mode. If you check the status of the message, it will report that there was a network error.

STATUS

Microsoft has confirmed this to be a problem in version 4.0 of Microsoft Exchange. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.