All major hosters use their internal hostname. For example, when sending mail from a hosted domain my-domain.com, the smtp gateway sends the HELO smtp01.hoster-name.net etc.

I asked for the same feature some time ago, but I arrived at the conclusion that it's the best like it's right now.

LE:
Also, you probably won't have reverse dns for each EHLO for hosted domains, so your mails will get rejected.

In this specific case - White label'ing the MTA

First - just wanted to say great work on iRedMail - it's a great & painless way to have a mail server running in next-to-no time.
Apart from a few minor issues - it was a painless install on Ubuntu 9.10 x64.

There's a few config type issues - mostly distro based I think:
On ubuntu amavisd is amavisd-new, etc
The default graylisting config is a little severe - I had to switch it to training-mode to stop everything getting deferred.
Adding a new domain via the iRedMail web ide doesn't generate dkim keys or change the amavis conf file to include those domains.  While I'm accepting mail ok for multiple domains - I'm worried there's other config files that need to be updated to include extra domains.

The only issue I'm experiencing that I can't find a way around is how to change, per-hosted mail domain, the hostname in the HELO banner.
The server accepts mail ok for multiple domains - but doesn't change the hostname in the HELO banner based on the domain-name used when an mta connects.

A better explanation can be seen via:
http://www.dnstrouble.com/index.php?con … king.co.uk
http://www.dnstrouble.com/index.php?con … osting.com

ie:
Trying 204.232.210.31...
Connected to mail.inspiredthinking.co.uk.
Escape character is '^]'.
220 mail.developedhosting.com ESMTP iRedMail (Ubuntu)

From what I understand - this [http://www.postfix.org/postconf.5.html#smtp_helo_name] refers to a single domain - rather than changing the HELO banner based on that used by the connected MTA.