Read receipt is not processed when you send a message to another Exchange organization

When you request a read receipt for a message that you send to a recipient in another Exchange organization, you may not receive a notification when the recipient reads the message.

This issue may occur if either of the following conditions are true:

• You send a message from an Exchange Server 5.5 computer to a recipient hosted on an Exchange 2000 Server computer or on an Exchange Server 2003 computer.
• You send a message from an Exchange 2000 Server computer or from an Exchange Server 2003 computer to a recipient hosted on an Exchange Server 5.5 computer.

This error may occur in either of the following scenarios:

• When an Exchange Server 5.5 recipient sends a message that contains a read receipt request, Exchange Server formats the read receipt request in the message header as a delivery receipt (Return-Receipt-To). When the Exchange 2000 Server computer or the Exchange Server 2003 computer receives this message, it interprets the read receipt as a delivery receipt request (PR_ORIGINATOR_DELIVERY_REPORT_REQUESTED set to TRUE).
• When an Exchange 2000 Server or an Exchange Server 2003 recipient sends a message that contains a read receipt request to a recipient hosted on an Exchange Server 5.5 computer, the Exchange 2000 Server computer or the Exchange Server 2003 computer formats the read receipt as Disposition-Notification-To, which Exchange Server 5.5 cannot interpret.

Microsoft has confirmed that this is a problem in Microsoft Exchange Server 5.5.

To work around this problem, turn on either Transport Neutral Encapsulation Format (TNEF) or Rich Text Format (RTF) messaging in the Internet Mail Service and on the Exchange 2000 server in the Exchange 2000 Server or Exchange Server 2003 organization and the Exchange Server 5.5 organization. Read receipts and delivery receipts will then be processed correctly.

The Return-Receipt-To parameter, although widely used, is not an SMTP standard. A read receipt request should be formatted as Disposition-Notification-To. However, Exchange Server 5.5 does not recognize the Disposition-Notification-To parameter and therefore does not generate a read receipt when requested.

All read receipts and delivery receipts sent from Exchange Server 5.5 are mapped as Return-Receipt-To, which Exchange 2000 Server or Exchange Server 2003 interprets as a delivery receipt request.