Thanx Richard; one of the LISTSERV header munging problems
seems to be solvable.
 
There is one other problem which needs some thoughts: The non
BSMTP mailers, i.e. the RFC822 mailers. In the following I assume
that there will be no RFC822 mailers anymore.
 
What remains of LISTSERV's header munging?  LISTSERV should no
longer modify the header at all. It should just add some
lines at the beginning:  One Received: line and one Newsgroup:
line (or whatever identifies the "conference").  It may add a
Sender: line if the list maintainer wants error reports. Then
LISTSERV explodes the list and sends a BSMTP/DIST JOB to
mailer/listserv.
 
The fact that some mail systems send error messages to From: fields
or even to Reply-To: fields is a different problem and it CANNOT be
completely solved. These systems should be identified by some
network police and the people responsible for these systems
should be invited to change the software.  The known heuristics in
LISTSERV, DATABASE that detect mail from postman, mailer-daemon etc.,
they can be left as is.
 
Non delivery reports in RFC822 systems are a special problem when these
systems are gatewayed to X.400 systems. If you read RFC987 you will
find that Sender: is used here for another purpose in a similar way
as RFC822 misuses the field but LISTSERV should not make the situation
worse using its private interpretation of RFC822.
 
 
Peter