On several occasions I’ve noticed that Comcast seems to be blocking port 25 on their internet connections. This, of course, is an issue for SBS 2011 networks and outgoing SMTP email. For most cases I use a Smart Host for outbound email such as DynDNS. However, the built in wizard for configuring the Smart Host does not allow you to specify which port to use. Fortunately, with two simple powershell commands you can change this.
- Open Exchange Management Shell (EMS) as an administrator.
- Type the following cmdlet to list all the current Send Connectors.
- Using the SMTP Send Connector name extracted from the above cmdlet type the following cmdlet to change to the desired port. (2525 in this case)
Set-SendConnector “SMTP Send Connector Name goes here” -Port 2525
Hat tip to prolateral.