How to enable custom mail HELOs

Question

How do you enable custom mail HELOs?

Answer

1. Log in to WHM as the 'root' user.
2. Navigate to Home / Service Configuration / Exim Configuration Manager.
3. Under the Basic Editor, click the Domains and IPs tab.
4. Disable the Use the reverse DNS entry for the mail HELO/EHLO if available option.
5. Enable the Reference /etc/mailhelo for custom outgoing SMTP HELO option.
6. Access the server's command line as the 'root' user via SSH or Terminal in WHM.
7. Open /etc/mailhelo in your preferred text editor.

8. Add the domains and mail HELOs you would like these domains to use with the domain.name: domain.helo format:

   CONFIG_TEXT: example.com: example.com
   sub.example.com: example.com
   example.net: example.net
   addon.example.net: example.net
   *: hostname.example.com

   Note: The last entry in the above example is a wildcard that represents every domain not explicitly listed. It is considered to be the default mail HELO.

9. Save the changes and exit the text editor.

Additional Resources

Exim Configuration Manager Basic Editor: Domains and IPs

How to Configure the Exim Outgoing IP Address