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How to enable custom mail HELOs

Daniel Pearsall
  • Updated

Introduction

This how-to is meant to demonstrate how to enable and add custom mail HELOs.

 

Procedure

To enable Exim to use custom mail HELOs, follow these steps:

  1. Navigate to WHM >> Exim Configuration Manager >> Basic Editor >> Domains and IPs.
  2. Disable the Use the reverse DNS entry for the mail HELO/EHLO if available option and enable the Reference /etc/mailhelo for custom outgoing SMTP HELO option.
  3. Open or create /etc/mailhelo with the text editor of your choice and add the domains and mail HELOs you would like these domains to use to the file.

Here is an example of a custom /etc/mailhelo file:

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

 

The domain and its custom mail HELO are defined in pairs. For example, example.com uses example.com as its mail HELO, sub.example.com uses example.com as its mail HELO, and so on. The last entry, *, is a wildcard symbol that represents every other domain not already listed in /etc/mailhelo and is considered to be the default mail HELO.

 

You can read more about the configuration options and /etc/mailhelo file in our documentation here:

Reference /etc/mailhelo for custom outgoing SMTP HELO

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