[ On Tuesday, May 15, 2001 at 12:49:51 (-0400), Dave C. wrote: ]
> Subject: Re: [Exim] RFC 2821 and "headers_sender_verify"/"headers_checks_fail"
>
> > The autoresponder should still use a legal and valid SMTP envelope
> > sender address other than "<>" of course.
>
> Erm?
>
> Any automatically-generated mail (especially generated in response to
> receipt of a message, regardless of wether its an nondelivery report or
> anything else) should always use <> as the envelope sender to prevent
> mail-loops (eg, the classic 'dueling autoresponders' situation)
Ah, ... NO!
Any mail that comes from outside the mail system istelf (i.e. the MTA
itself), be it automatically generated or not must have a valid return
address. The only thing that should ever generate empty sender
addresses is the MTA itself. An autoresponder is a *user* agent, not an
MTA.
The "dueling autoresponder" situation is trivially handled by other
simple and long proven techniques (eg. "Precedence:" headers).
--
Greg A. Woods
+1 416 218-0098 VE3TCP <gwoods@???> <woods@???>
Planix, Inc. <woods@???>; Secrets of the Weird <woods@???>
