🚀 go-pugleaf

     As the developer of one of the major Internet mailsystems which
has redistribution-style mailing lists, I would like to comment on
the recent exchange of messages regarding error reports and how they
should be sent.

     I definitely sympathize with the people who have to pay for
electronic mail messages.  I would certainly agree that they have
every reason to feel badly treated by being made to pay for zillions
of mail failure notifications from some large mailing list.

     On the other hand, there is another side.  Some of the mailsystems
involved, mine included, behave the way they do for historical reasons.
In particular, much of the code was written long before Return-Path and
conventions such as "-REQUEST" existed.  There are two issues involved.

     First is the support of null Return-Path.  The TOPS-20 mailsystem
literally cannot tell the difference between a null Return-Path and a
non-existant Return-Path.  The distinction is important; the former
case means "errors should be discarded" and the latter means "errors
should be send to the 'sender', an abstract entity which may ultimately
be determined by parsing the message header."  The result is the silly
behavior of sending an error to a Mailer Daemon or other entity that
specified it didn't want errors returns to it.  This could be fixed,
but it is non-trivial to do.

     Second is the official status of conventions such as "-REQUEST".
Unfortunately, there are no printed standards which specify this sort
of convention, merely folklore.  It is very difficult for software
developers to develop a portable product for a wide range of environments
to deal in folklore for a single environment.  More importantly, it is
not at all clear to me how global "-REQUEST" is, or what the rules to
determine its appropriateness.  This is at least partially due to the
many kinds of mailing lists which can exist and the hazy distinction
between a "mailing list" and a "forwarding" which several mailsystems,
TOPS-20 included, have.
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