On 29 Jun 2018, at 15:30, David Cunningham via Exim-users wrote:
> Hi All,
>
> All bounce-backs have an envelope from of <>.
Yes, they do. Using the null sender for MTA-generated messages has been
part of the SMTP standard forever. It is not optional. It is not a
matter of choice. A server which does otherwise is a broken server and a
public nuisance. A purported "bounce" message with a non-null envelope
sender SHOULD NOT be delivered and MAY be considered prima facie
evidence of the originating machine being under the control of a
malicious actor, because this behavior has been exhibited by
(desperately stupid) spambots.
> I need to be able to set this to something.
That is not true. You will survive conforming to the standard. Using a
non-null sender on bounces is bad and wrong and no one should ever do it
for any reason. It is better that you simply blackhole all of your
bounces rather than send broken ones.
> I am using a smart host that will not accept emails from <>.
Are you convinced that "smart" is the right word here? I'm quite certain
it is not. Maybe you meant "grossly misconfigured outbound relay"
instead?
> I need to to be set to postmaster or don-no-reply or something of the
> like.
The consequences of doing so will be remote double-bounces aimed at the
envelope address (which had best accept all mail, or you're running an
echo chamber,) your bounces going missing silently, possible public
blacklisting, and almost certain private undiagnosable blacklisting.
These annoying consequences will be entirely deserved.
With that said, a conditional string expansion in the return_path option
of the smtp transport would be the way to do this. See the docs:
http://www.exim.org/exim-html-current/doc/html/spec_html/ch-generic_options_for_transports.html
http://www.exim.org/exim-html-current/doc/html/spec_html/ch-string_expansions.html
Something *like* (untested):
return_path = ${if eq {$return_path}{} {postmaster@???}}
But in case I wasn't clear: DO NOT DO THIS!
(yeah, I know, you won't listen...)
--
Bill Cole
bill@??? or billcole@???
(AKA @grumpybozo and many *@billmail.scconsult.com addresses)
Currently Seeking Steadier Work:
https://linkedin.com/in/billcole
