By default, Exchange Server 2007 uses port 25 to send SMTP email using Send Connectors. On occasion you may be required to configure an Exchange Send Connector to use a different port – For example, TCP port 465 is commonly used for SMTP over SSL for secure SMTP communication using the SSL protocol. Configuring the port is not exposed through the Exchange Management Console (EMC), it must be configured from the Exchange Management Shell (EMS).
To get a list of the Send Connector names configured in your organization, run:
Get-SendConnector
Here’s the one-liner that configures a Send Connector to use port 465:
Set-SendConnector “Your SMTP Send Connector” -Port 465
If you’re using a Microsoft Edge server, you will need to configure this from any server that is not running the Edge role. You will also need to wait for an EdgeSync operation or force it manually:
Start-EdgeSynchronization
No services need to be restarted for this change to go into effect.