1- Take Zimbra backup or VM snapshot before doing any changes

2- Enter the following command to change SMTP Banner:

# su - zimbra

$ zmlocalconfig -e postfix_smtpd_banner="yourmailserver.yourdomain.com"

3- Then if you want to change HELO/EHLO names, enter:

$ zmprov mcf zimbraMtaMyHostname yourmailserver.yourdomain.com

4- If you want to disable adding X-originating (Client‘s internal-LAN IP) to email headers:

$ zmprov mcf zimbraSmtpSendAddOriginatingIP FALSE

5- Then restart Zimbra Services:

$ zmcontrol restart

How to test whether it is working:

1- Telnet to your mail server from Windows cmd or Unix GNU telnet client

telnet yourmailserver.yourdomain.com 25

- It firewall allows you to access, doing telnet to port 25 should get your server to greet you with 220 yourmailserver.yourdomain.com

2- In telnet, type following to get HELO response

> helo yourmailserver

You should get:

250 yourmailserver.yourdomain.com

3- In telnet, type following to get EHLO response

ehlo yourmail

You should get:

250 yourmailserver.yourdomain.com

Rest of EHLO lines according to yoru server config, such as MTA mail size, STARTLS

How to change SMTP Banner, HELO,EHLO Greetings for Zimbra