Topic Last Modified: 2005-11-18

The Microsoft® Exchange Server Analyzer Tool queries the Active Directory® directory service to determine whether the configured value for the msExchSmtpOutgoingPort attribute has been altered from the default value of 25. By default, the msExchSmtpOutgoingPort attribute is configured for TCP port 25. If the Exchange Server Analyzer finds that this attribute is configured for a port other than 25, a warning is displayed.

By default, Simple Mail Transfer Protocol (SMTP) servers are configured to accept inbound connections on TCP port 25. The msExchSmtpOutgoingPort parameter represents the TCP port to which this Exchange server will attempt to connect on all remote SMTP servers. If the remote SMTP servers have not been configured to listen on this port, a connection cannot be made.

Unless some, or your entire internal messaging infrastructure has been modified to use non-standard ports, it is recommended that you use TCP port 25 for all SMTP communication.

To view or change the default outgoing SMTP port

  1. In Exchange System Manager, expand Servers, expand an Exchange server, expand Protocols, and then expand SMTP.

  2. Right-click an SMTP virtual server (for example, Default SMTP Virtual Server) and click Properties.

  3. Click Delivery, and then click Outbound Connections.

  4. In the TCP port field, enter the port you want to use for outbound connections. Every remote SMTP with which you want to communicate must be configured to accept connections on the specified port. In most cases, you will not want to change this value.

  5. Change this field as needed, and then click OK to save your changes.

  6. Click OK to close the Properties dialog box of the SMTP virtual server.

For more information about SMTP virtual server settings, see the following Microsoft Knowledge Base articles: