From maechler at stat.math.ethz.ch  Mon Nov 24 19:23:07 2003
From: maechler at stat.math.ethz.ch (Martin Maechler)
Date: Mon Nov 24 19:22:16 2003
Subject: [Rd] R Mailing lists: "Sender:" now sometimes VERPs
Message-ID: <16322.19595.637264.353268@gargle.gargle.HOWL>

{BCC'ed to three Core groups}

Following the recommendation of the mailman developers,
I have activated occasional "VERP"ing for our mailing lists.
(and will turn it off again, after about a day or so).

Here is the mailman "comment-docu" on this :

# These variables control the format and frequency of VERP-like delivery for
# better bounce detection.  VERP is Variable Envelope Return Path, defined
# here:
#
# http://cr.yp.to/proto/verp.txt
#
# This involves encoding the address of the recipient as we (Mailman) know it
# into the envelope sender address (i.e. the SMTP `MAIL FROM:' address).
# Thus, no matter what kind of forwarding the recipient has in place, should
# it eventually bounce, we will receive an unambiguous notice of the bouncing
# address.
#

This is in order to better track down those invalid e-mail addresses 
with mail servers that do not send back bounces which mailman
(the mailing list software) understands.
Otherwise I would have to manually find out what went wrong and
disable / unsubscribe unused addresses.  This is no longer an
option, e.g., for R-help with more than 2000 addresses
subscribed and more than a dozen subscriptions changes every day.

Consequence:  
  The mails are sometimes (every 10th time) sent out
  individualized with a "Sender: " header that now looks like
  this (for me):
  >> Sender: r-devel-bounces+maechler=stat.math.ethz.ch@stat.math.ethz.ch
  instead of
  >> Sender: r-devel-bounces@stat.math.ethz.ch

This is both *slower* and may require that you change your mail
pre-sorting if it currently relied on "Sender:".

E.g., I'd use  procmail rule for the R lists such as

 :0:
 * ^Sender: (r-|bioco)[-a-z]*-(admin|bounces(\+.*)?))@stat\.math\.ethz\.ch
 R-lists.spool

where the  "(\+.*)?"  allows for the occasional VERPing.

I hope these consequences are small enough,
and will help to rationalize the keeping of a clean mailing list
address base.

Martin Maechler <maechler@stat.math.ethz.ch>	http://stat.ethz.ch/~maechler/
Seminar fuer Statistik, ETH-Zentrum  LEO C16	Leonhardstr. 27
ETH (Federal Inst. Technology)	8092 Zurich	SWITZERLAND
phone: x-41-1-632-3408		fax: ...-1228			<><


[Rd] R Mailing lists: "Sender:" now sometimes VERPs
Martin Maechler