On Tue, 19 Dec 2000 15:31:26 -0500, Eva Kalman <[log in to unmask]> wrote:

> For lists with SHORTHDR specified, LISTSERV deletes Return-Receipt-To
> headers from postings.  

True, along with many other header lines, including those needed for the mailer
pgm to correctly display MIME messages.  SHORTHDR is not receommended for this
and other reasons.

> However, MS Exchange apparently also embeds
> something in a MIME attachment to request an acknowledgement, which
> LISTSERV cannot remove.   

This may be in the MS_TNEF attachment WINMAIL.DAT (but the format of WINMAIL.DAT
is not publically documented), which current versions of LISTSERV usually remove
the entire attachement, since it has no meaning to non-MS mailer pgms.

> Exchange gets this, but doesn't have the
> Return-Receipt-To header anymore to reply to, so it goes back to the
> envelope sender (which is the Errors-To address, which is owner-listname).

I'm not sure how Exchange behaves but Return-Receipt is to acknowledge delivery
receipt. It is not necessarily the proper address for the reporting of delivery
errors.

> MS Exchange systems apparently send DSNs and receipts to the envelope
> sender of a message instead of the real sender (the "From:" line).

This behavior is mandated by RFC821.  The 'Envelope' Sender 
(MAIL FROM:<address> or Return-Path: address) is the only proper address for the
reporting of SMTP delivery errors.  The RFC822 From: has no place in this
process.

> Listserv sets the envelope sender to the "Errors-To" address, because
> that's where errors will usually go, and in most lists, this is set to
> owner-<I>listname</I> by default.

LISTSERV reserves the OWNER-listname@hostname address for this purpose and
always has.  This not the same as any Errors-To: header (which is an RFC822
header whose use is defined as "Non-Standard, Discouraged" by RFC2076.)
LISTSERV does not set the MAIL FROM:<address> to the same as Errors-To: at all.
The Errors-To: will be ignored by LISTSERV, but the MAIL FROM:<address> will be
set correctly.  The Errors-To: header, if present, may happen to be point to the
same address but if so it is not set that way by LISTSERV.

> So far, all we can suggest is that list owners ask their list
> subscribers to refrain from requesting Return Receipts when sending
> to a list.  

This is good advice. 'Return Recipt' may make sense in a closed corporate
environment where everyone is using the identical mail program, but it has no
place on the broader internet where many differing mail programs are used.
LISTSERV lists used in such closed corporate environments may be able to retain
these proprietary mail program features, but only with special configurations.

> Otherwise, list owners will need to have a filter in their
> client to throw away these messages.  

This also is good advice.

> You could blank out the "Errors-To"
> keyword in the LISTSERV configuration header but then you wouldn't
> receive real errors such as address delivery problems.

If you don't define an Errors-To= in the List Header this will default to the
non-quiet List Owner(s).  You can't 'blank-out' this setting.