XCON: MTA Queue Blocked by NDR or Delivery Receipts

• Microsoft Exchange Server, versions 4.0 and 5.0

SYMPTOMS

An Exchange Server site that backbones over a foreign X.400 system to another Exchange Server site develops a message backlog for mail destined for the remote Exchange Server site. This message backlog is unrelated to any network communication problems. The message delivery problem may be unidirectional; that is, messages are being delivered from the remote site, but not to the remote site.

CAUSE

If a report message (that is, a non-delivery report [NDR], or a delivery receipt) is returned from the remote site and the foreign X.400 system used as a backbone adds unanticipated encoding for the property Report- Additional-Info, the message may block the MTA queue.

STATUS

Microsoft has confirmed this to be a problem in Microsoft Exchange Server version 4.0. A supported fix is now available, but has not been fully regression-tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information.

Microsoft has confirmed this to be a problem in Microsoft Exchange Server version 5.0. This problem has been corrected in the latest U.S. Service Pack for Microsoft Exchange Server version 5.0. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

   S E R V P A C K