🚀 go-pugleaf

Stew,

As a maintainer of several mailing lists, and the former maintainer of
one very large list, I tend to agree with your approach, but only for
two annoying classes of returned mail: Quota exceeded and the
gratuitous Failed after n days, will try another m days (or
equivalent).  ALL other failed mail should be returned to the list
maintainer at the -REQUEST address (and NOT to the maintainer of
record).

(All of the lists which originate on this host have a -REQUEST entry,
which is, in turn, a two-entry mailing list: one entry for the
maintainer and one to a special mail file set up to receive copies of
such mail for subsequent processing.  The first entry simply serves to
notify the maintainer that there is a problem.

Unfortunately, we do not yet have the facility that automatically
inserts/replaces the Return-Path header item with the -REQUEST
addresses for mail sent to these lists.  I, for one, would welcome
such a feature to lift it out of the "folklore" arena and made a
standard... and it doesn't *have* to be set up as -REQUEST; it could
be a single, specially prefixed extry in the list itself.)

However, even with Return-Path, there are certain sites which ignore
that entry and insist on returning mail to the originator of the
message...

--Frank