Hello Bob, 

Unfortunately no. 

The only way to have SmarterMail send out on another port wold be to get a Gateway set up. In the Gateway settings you can specify a port. 

Depending on the gateway you may end up running in to the same issue though. All email services listen on Port 25, but not all of them are listening on the other SMTP ports ( 587, 465 ). 

Depending on your service provider for your server you may be able to request to have the port opened. Some like AWS come with the port closed unless you request to have it opened. 

https://repost.aws/knowledge-center/ec2-port-25-throttle

I hope this helps. 

~Tony

Email servers cannot run on IBM Cloud.

Instead of being smart, they disabled port 25 for all scenarios.