Forcing TLS encryption with MS Exchange

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Jenni Posts: 697 Former F-Secure Employee

This article describes how you can force TLS encryption with Microsoft Exchange.

Do as follows:

  1. 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 25


  2. If you can see STARTTLS, Exchange is able to use TLS:


  3. Go to System > SMTP Encryption > Settings and set Enable TLS to On:


  4. Go to System > SMTP Encryption > TLS Settings and add your email server IP address to the list with following settings: