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Path: utzoo!watmath!clyde!burl!hou3c!stew@lhasa.UUCP
From: stew@lhasa.UUCP
Newsgroups: net.mail.msggroup
Subject: Non-deliverable messages
Message-ID: <8404300256.AA05203@harvard.UUCP>
Date: Sun, 29-Apr-84 22:38:00 EDT
Article-I.D.: hou3c.515
Posted: Sun Apr 29 22:38:00 1984
Date-Received: Tue, 1-May-84 08:13:10 EDT
Sender: ka@hou3c.UUCP (Kenneth Almquist)
Lines: 46
To: harvard!msggroup@Brl-Mis.ARPA

Sending all the messages failing on a distributed mailing list should
\not/, in my opinion, go back to either the real sender or the mailing
list coordinator, unless there is no alternative.

Coordinators of large mailing lists often have other things to do with
their time.  Making them worry about why some random mailbox two gateways
and three redistributions down the line is not accepting mail at the moment
is not really reasonable.  I propose that the message be returned to the
handling agent closest to the failing mailbox.  This may be the postmaster
at the destination site, or at a redistributing site, or it may well be
the -REQUEST mailbox.  The motivation is obviously that the closer to the
failure we can hit, the more likely we are to find the responsible party.

This scheme requires that every redistribution point put a Resent-From:
or Redistributed-From: header line into the message.  These would then
be checked first for return addresses.  The drawback here, of course,
is that the delivery software would have to be changed to do this if
it doesn't already.  An alternative would be to have each redistributer
make itself the Sender.  This is, in fact, how I read RFC822, section
4.4.4:  "The 'Sender' field mailbox should be sent notices of any problems
in transport or delivery of the original messages.  If there is no 'Sender'
field, then the 'From' field mailbox should be used."  There is also
provision for a 'Resent-Sender' field.  However, the standard does not
dictate when a 'Resent-' address should be given precedence, only that
it be 'more recent'.

Ideally then, the field to use is 'Resent-Sender', which should be
interpreted as the agent which most recently handled the message,
and which, presumably, is related to the mechanism for storing the
address which failed.

So how do we implement this?  In my case, as an example, MSGGROUP sends
to MSGGROUP-INCOMING@HARVARD.ARPA which is an alias that includes, among
other addresses, lhasa!msggroup-incoming.  This sends mail via (pseudo-)
uucp mail to my machine, lhasa, which has another alias.  So when mail to
my mailbox fails, the message should be returned to lhasa!postmaster.
Since I \am/ lhasa!postmaster this will probably also fail, though!
So it ought to go to the next most recent agent, harvard!postmaster.

If anyone can show me how to mung sendmail config files to make this
happen, I will see that you are canonized :-)

Stew Rubenstein
lhasa!stew@harvard.arpa
{allegra!ima,ihnp4,decvax!genrad!wjh12}!harvard!lhasa!stew@UUCP
Harvard Chemical Labs, 12 Oxford St., Cambridge, MA 02138 @ U.S. Mail