How to disable non-SSL email logins

Introduction

To increase security on your server, you may want to prevent insecure authentication to the mail services. This article provides the steps to force encryption for email authentication.

Procedure

1. Log into WHM as the ‘root’ user.
2. Navigate to "Home / Service Configuration / Mailserver Configuration"
3. Set the "Allow Plaintext Authentication (from remote clients)" option to "No."
4. Scroll to the bottom of the page.
5. Click the  "Save Changes" button.
6. Navigate to "Home / Service Configuration / Exim Configuration Manager."
7. Click the "Security" tab.
8. Set the "Require clients to connect with SSL or issue the STARTTLS command before they are allowed to authenticate with the server." option to "On."
9. Scroll to the bottom of the page.
10. Click the "Save" button.

Additional resources

Mailserver Configuration

Exim Configuration Manager Basic Editor: Security