How to change HELO hostname

EHLO (or HELO) identifies a host at the start of an SMTP protocol connection. In zimbra, you can change the EHLO (or HELO) sent to other smtp servers and set the banner used to greet other smtp servers or clients. Changing HELO

1. Switch to the zimbra user. su - zimbra
2. Change the config setting. zmlocalconfig -e postfix_smtp_helo_name = 'mail.domain.com'
3. Run the following command to apply it immediately. postconf -e smtp_helo_name = 'mail.domain.com'

Changing the greeting banner message

1. Switch to the zimbra user. su - zimbra
2. Change the config setting. zmlocalconfig -e postfix_smtpd_banner = '$smtp_helo_name ESMTP $mail_name'
3. Run the following command to apply it immediately. postconf -e smtpd_banner = '$smtp_helo_name ESMTP $mail_name'