Emerito Limited - SBS smtp on port 587

SBS smtp on port 587

Should set up a Virtual SMTP server that requires authentication (ie untick Anonymous), allows relaying for authenticated users and listens on port 587 (that is the IANA defined port for authenticated SMTP email submission).

Then add it as a local bridgehead in the existing SMTP Connector, so that it will use that for outbound deliveries.

Add rules to your firewall to allow inbound access to port 587 and forward/publish/whatever that to the SBS.

In the client software, change the outbound SMTP port to 587, and set them to authenticate.