XCON: HP Openmail Users Cannot Reply to SMTP Mail

• Microsoft Exchange Server, version 4.0
• Microsoft Exchange Server, version 5.0

SYMPTOMS

If mail is sent from an Internet user to an X.400 Mail system through the following path

   Exchange IMC -> Exchange -> Exchange X.400 Connector

CAUSE

Because the recipient on the X.400 system is not in the Microsoft Exchange Server global address list, the Internet Mail Connector (IMC) encapsulates the recipient's address. This encapsulation is normally stripped by another IMC later in the message path. However, in this particular scenario, there is no other IMC. Thus, the Microsoft Exchange Server message transfer agent (MTA) passes the encapsulation through as an additional Domain Defined Attribute (DDA) attribute. On the reply, the IMC does not recognize the DDA attribute, and returns the reply as non-deliverable.

WORKAROUND

Add the users on the receiving X.400 mail system to the global address list.

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

MORE INFORMATION

The X.400 Mail System recipient can look at details of the Internet message for the sender and will see an additional DDA attribute of MSXENCAP:SMTP. The DDA type is MSXENCAP and the DDA value is SMTP. This issue is resolved by stripping off this DDA information. The recipient might also notice that the NDR from the reply is generated from the IMC, and that details on the To: line resolve to a correct SMTP address. This occurs because the IMC uses the P2 header information in the NDR, but uses the P1 information to actually try to process the message.