Forcing TLS encryption with MS Exchange This article describes how you can force TLS encryption with Microsoft Exchange.
Do as follows:
- Make sure that Exchange can handle inbound mail traffic with TLS. Establish a connection to the email server port 25. Run the following command:
telnet youdomainhere.com 25
: 
- If you can see STARTTLS, Exchange is able to use TLS:
- Go to System > SMTP Encryption > Settings and set Enable TLS to On:
- Go to System > SMTP Encryption > TLS Settings and add your email server IP address to the list with following settings:
