I run postfix my servers to allow websites to send email. I'm using it as a drop-in for sendmail proper.

When an email is sent the HELO string seems to contain localhost. This wouldn't be a problem except that one of my clients has just said that an email was returned to them from a spam blocker saying that localhost cannot feature inside the HELO string. Awesome.

So I edited /etc/mailname to be my main domain name. And I edited /etc/postfix/main.cf so that:

smtpd_banner = ESMTP $mail_name

Yet this is what I see in the header of a sent email (after restarting postfix):

Delivered-To: [email protected]

Received: by 22.194.173.22 with SMTP id bi10csp117521wjc;

        Tue, 2 Apr 2013 07:24:18 -0700 (PDT)

X-Received: by 10.68.22.168 with SMTP id pt8mr24540246pbb.10.1364912657736;

        Tue, 02 Apr 2013 07:24:17 -0700 (PDT)

Return-Path: <[email protected]>

Received: from localhost (example.com. [22.22.22.22])

        by mx.google.com with ESMTP id l6si2328296pao.283.2013.04.02.07.24.16;

        Tue, 02 Apr 2013 07:24:17 -0700 (PDT)

I've subbed my domain with example.com.

What do I need to edit to quash the evil reign of localhost?!