XCON: NDR When Replying to Another Exchange Organization

When you reply to a message sent from another Microsoft Exchange Organization or from another Site within the same Organization, you may immediately receive the following Non-Delivery Report (NDR) by the local Message Transfer Agent (MTA):

This behavior occurs when the two Microsoft Exchange Organizations are connected via the X.400 Connector, or when two Sites are connected via the X.400 Connector with the Address Space Tab configured, and have the Allow MSExchange Contents setting enabled.

When a computer running Microsoft Exchange Server sends a message to another Exchange Server computer, the P1 for that message contains only the X500 Distinguished Name (DN) for the recipient's address. When the recipient replies to the message, they reply to the DN of the message originator. However, in seperate Exchange Organizations, as well as two Sites configured with the Address Space Tab, this fails because the DN is only comprised of the Organization and Site names.

To work around this behavior, the administrator needs to go to the properties page for the X.400 connector that connects the two Exchange Organizations or Sites and do the following:

1. Click the Advanced tab.
2. Under X400 Link options, click to clear the Allow MSExchange Contents setting.
3. Restart the MTA Service.

Now when messages are sent to the other Exchange Organization or Site, a content conversion occurs and the message P1 changes to a true X.400 O/R address that is properly handled by the other Exchange Organization or Site.