ScriptInstallation.In

smtpd_banner

smtpd_banner banner in /etc/postfix/main.cf will allow you to set SMTP server HELO string. On my server i changed it as follows.

smtpd_banner = $myhostname BizHat.com Mail Server

server22# telnet server22.hosthat.com 25
Trying 69.46.2.17...
Connected to server22.hosthat.com.
Escape character is '^]'.
220 server22.hosthat.com BizHat.com Mail Server
QUIT
221 2.0.0 Bye
Connection closed by foreign host.
server22#

The smtpd_banner parameter specifies the text that follows the 220 code in the SMTP server's greeting banner. Some people like to see the mail version advertised. By default, Postfix shows no version.

You MUST specify $myhostname at the start of the text. That is an RFC requirement. Postfix itself does not care.

#smtpd_banner = $myhostname ESMTP $mail_name
#smtpd_banner = $myhostname ESMTP $mail_name ($mail_version)