Delay Delivery Status Notifications and TURN/ETRN/ATRN

In Microsoft Exchange 2000 Server and in Microsoft Exchange Server 2003, messages that are held in the queue for TURN/ETRN/ATRN may cause Delay Delivery Status Notifications (DSNs) to be generated. This behavior occurs when a connection closes and a specific time period elapses. The situation can become critical for environments where most of the outbound mail is queued. The Delay DSNs add to the queue lengths, and you may lose control of the server's state because of the large number of messages.

This behavior can occur if the Delay Notification time is set too low.

Ensure that the Outbound Delay Notification setting is high enough. The default is 12 hours. Use the following procedure to adjust this setting on your Exchange server:

1. Start Exchange System Manager, and then click your server.
2. Under your server, double-click the Protocols folder.
3. Under the Protocols folder, double-click the SMTP folder.
4. Under the SMTP folder, click your SMTP virtual server.
5. Right-click the virtual server, and then click Properties. The Delay Notification setting is located on the Delivery tab. Adjust the setting for your environment.
6. Repeat this procedure for each SMTP virtual server that you have created.