Quoth Greg A. Woods on Tue, May 15, 2001:
> 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.
Why?
> The "dueling autoresponder" situation is trivially handled by other
> simple and long proven techniques (eg. "Precedence:" headers).
Precedence: headers are not mentioned in any RFC, so depending on
these headers is Not A Good Thing[tm]. Empty envelope sender
address, OTOH, is well defined in the RFCs and is widely
recognized as the sign of "don't send me bounces".
Vadik.
--
To the systems programmer, users and applications serve only to
provide a test load.