How to change HELO message in Zimbra Mail Server

To change SMTP HELO on a Zimbra server to match the configured MX record, follow the procedure below. Log in as the zimbra user.

[root@EzyMailHosting ~]#  su - zimbra

Change SMTP HELO with:

[zimbra@EzyMailHosting ~]$ postconf -e smtp_helo_name='emailserver.yourdomain.com'
[zimbra@EzyMailHosting ~]$ zmlocalconfig -e postfix_smtp_helo_name = 'emailserver.yourdomain.com'

Replace emailserver.yourdomain.com with the domain name you want to use. Change the SMTP Banner with:

[zimbra@EzyMailHosting ~]$ postconf -e smtpd_banner='$smtp_helo_name ESMTP $mail_name'
[zimbra@EzyMailHosting ~]$ zmlocalconfig -e postfix_smtpd_banner = '$smtp_helo_name ESMTP $mail_name'

Reload the configuration to apply the SMTP HELO settings on the Zimbra server.

[zimbra@EzyMailHosting ~]$ zmmtactl reload