postfix:
> Hi,
>
>
> I have been researching an "issue" we are having with returned emails.
>
> We send out emails on behalf of our re-sellers of our voice mail
> product, but when the email fails to be delivered the bounce returns to
> us, rather that the From we had set (ie the re seller).
I have news for you: the From: message header does not specify where
undeliverable mail will be sent.
A compliant Internet mail implementation sends undeliverable to the
envelope sender address (the address in the "MAIL FROM" command in
the SMTP protocol, not the address in the From: message header).
See RFC 5321 for the protocol definition.
I recommend that you look at a protocol recording (captured with
tcpdump or the like) and see what your system sends in MAIL FROM
commands.
Your speculation about your HELO command affecting the return path
is almost certainly wrong. I have never heard of a mail system that
behaves that way.
Wietse
