On   Wed,   27   Aug   1997  16:05:56   -0600   "Michael   Loftis(ADMIN)"
<[log in to unmask]> said:

>Mostly  sites seem  to  be using  this  to tell  where  mail comes  from
>exclusively. If it doesn't  resolve (as in the case of  a blank) then it
>doesn't get there.

This is  a violation  of RFC821 reinforced  in RFC1123.  Certain messages
(bounces) are actually REQUIRED to use MAIL FROM:<>. Systems which reject
MAIL FROM:<> need to be fixed.

>1.8c seems to be "undecided" on when to use and when not to use a proper
>mail from.

MAIL FROM:<>  is used when  required by the  standards and then  in cases
where there is  no point in being  sent a bounce (which would  have to be
passed on to the maintainer - that's  you, that's a LOT of mail, and that
leads to a filter in your mail program which will also kill messages that
you SHOULD be  reading). Support for MAIL FROM:<> has  been mandatory for
15 years, there is  nothing "broken" about it and it is  a key element of
the SMTP standard (for loop prevention). Bouncing a message that has MAIL
FROM:<>  is  an inexcusable  and  extremely  dangerous violation  of  the
standards as it has the potential to  lead to a mailing loop, of which we
had one yesterday, to the  tune of 2000 ever-increasing messages. Luckily
this was  a Windows 3.1  site so when the  bounce reached 64k  their mail
program died and the  loop ended :-) The very purpose  of MAIL FROM:<> is
to suppress bounces  and avoid endless loops, as such  bouncing is one of
the  most irresponsible  acts  an  ISP can  possibly  commit (worse  than
allowing  spam, spams  at  least  do not  loop  and  increase with  every
iteration).

  Eric