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How to change SMTP port 25 to another port in Microsoft Exchange Server
Article ID: 274842 - View products that this article applies to.
This article was previously published under Q274842
This article explains how to change Simple Mail Transport Protocol (SMTP) port 25 to another port in Microsoft Exchange 2000 Server or in Microsoft Exchange Server 2003 or in later versions.
SMTP is the default protocol that Exchange 2000, Exchange 2003, Exchange Server 2007, or Exchange Server 2010 uses to communicate between Exchange-based servers within one site or between a server and the Internet. Therefore, if you change the port that is used to listen to SMTP traffic, you may experience wide-ranging and unexpected negative effects. When you change the default port configuration, you should carefully consider and test the configuration before you implement it in a production environment.
How to Change the SMTP Listening PortTo change the SMTP listening port on a server that is running Exchange 2000 or Exchange 2003 from port 25 to another port, for example, port 26, follow these steps:
Warning If you change this port number, the virtual server will not be reachable by other SMTP virtual servers that are configured to have the default (Outgoing) SMTP port 25.
How to Change the Outbound TCP PortNOTE: Every remote SMTP server that you want to communicate with must be configured to accept connections on the specified port. In most cases, you do not want to change the default port setting.
To change the outbound TCP port, follow these steps:
NOTE: For these steps, the Display routing groups check box is enabled on the Exchange Organization Name properties in a mixed mode site.
To change the SMTP port on a server that is running Exchange 2007 or Exchange 2010, follow these steps: