XCON: MTA X.400 1988 to 1984 Downgrade Failure Causes NDR

When a message is routed from a 1988 X.400 Connector over a 1984 X.400 Connector, the message transfer agent (MTA) correctly downgrades Common Names in the message content (P2), but doesn't downgrade Common Names in the message envelope (P1). If the receiving MTA is an Exchange Server MTA, it tolerates this error, but if the MTA is a foreign MTA, it may generate a non-delivery report (NDR) for the original message, with a diagnostic of Recipient Unknown.

If the recipient O/R Address on a message contains a Common Name, and the message is routed over a 1984 X.400 Connector (assuming the Allow MS Exchange Contents check box on the X.400 Connector Advanced property page is cleared), the Common Name should be downgraded. The downgrade consists of following the 1988 to 1984 downgrade rules, and converting the Common Name to a Domain Defined Attribute (DDA), of Type=Common, Value=Common Name.

This problem is caused by the 1988 to 1984 downgrade rules being incorrectly applied to the message envelope.

To resolve this problem, obtain the latest service pack for Exchange Server version 5.5. For additional information, click the following article number to view the article in the Microsoft Knowledge Base: The English version of this fix should have the following file attributes or later:

Component: MTA

Microsoft has confirmed that this is a problem in Microsoft Exchange Server version 5.5 SP1 and SP2. This problem was first corrected in Exchange Server 5.5 Service Pack 3.