When you configure two SMTP virtual servers and assign them as local bridgehead servers for two SMTP connectors, message delivery is not consistent in Exchange Server 2003 or in Exchange 2000 Server

Consider the following scenario. In a Microsoft Exchange Server 2003 or Microsoft Exchange 2000 Server organization, you create two SMTP virtual servers. You configure these virtual servers to send mail by using different outgoing ports. Then, you configure two SMTP connectors that include different address spaces. For example, one connector includes "domain_name.com". And, the other connector includes "domain1_name.com". Then, you assign each connector one of the SMTP virtual servers as the local bridgehead server. In this scenario, when you send a message to each address, only one message is delivered successfully. The message that is sent to the other address remains in the connector queue. Eventually, a non-delivery report (NDR) is generated for this message.

This behavior occurs because the Exchange Store driver selects the first virtual server that starts when the Exchange services are initialized. This virtual server hosts the send queue.

To work around this behavior, configure the SMTP virtual servers so that the outgoing port of one SMTP virtual server is the same as the incoming port of the other SMTP virtual server. To do this, follow these steps:

1. In Exchange System Manager, expand Administrative Groups, and then expand First Administrative Group.
2. Expand Servers, expand Protocols, and then expand SMTP.
3. Right-click Default SMTP Virtual Server, and then click Properties.
4. On the Delivery tab, click Outbound connections.
5. In the TCP port box, type the port that you assigned as the incoming port of the second SMTP virtual server. For example, type 2525.
6. Repeat steps 3 and 4 for the second SMTP virtual server.
7. In the TCP port box, type the incoming port number of the default SMTP virtual server. Typically, the incoming port number is 25.

This behavior is by design.

In the scenario that is described in the "Symptoms" section, the Exchange Store driver always selects the virtual server that starts first. The Exchange Store driver selects this virtual server even if the driver uses the address space of the connector to select the connector. Messages are not rerouted between SMTP virtual servers because the outgoing port of one virtual server differs from the incoming port of the other virtual server.

For more information about the behavior that is mentioned in the "Symptoms" section, visit the following Microsoft Exchange Team Blog Web site:Note The information on the Microsoft Exchange Team Blog Web site is provided "as is" without warranties and confers no rights.