Is your postmaster seeing mysterious misdirected messages that just say
"OK"?  Are your Microsoft Mail users having trouble subscribing to the
Windows 95 list, [log in to unmask]  If so, read on.
 
I would like to let people know about an unfortunate interaction
between very recent versions of LISTSERV and Microsoft Mail.  It causes
replies to LISTSERV command confirmation messages to be misdirected to
the MS Mail postmaster.  Other non-Internet Mail systems could be
affected too.  Here's what I think is happening:
 
(1) The MS Mail user sends a command to LISTSERV that requires
confirmation from the user.  An example is sending "SUBSCRIBE WIN95-L
firstname lastname" to [log in to unmask]
 
(2) LISTSERV sends back a confirmation message to the user.  In order
for the command to take effect, the user must reply with an OK and the
confirmation number within 48 hours.
 
(3) In very recent editions of LISTSERV 1.8b (not even all instances of
1.8b), the address in the SMTP MAIL FROM command (not the From header)
is null, meaning that no bounce messages should be sent back.  Earlier
versions of LISTSERV put LISTSERV's address here, with the result that
bounce messages went to the LISTSERV postmaster, who usually can do
nothing about them.
 
(4) The Microsoft SMTP gateway uses the address from the SMTP MAIL FROM
command (which may differ from the address in the From header) as the
address in the Microsolft Mail From field.  This is so that bounce
messages will go where they should.  However, Microsoft Mail cannot
handle a null value, so it substitutes "Postmaster".
 
(5) When the user replies to the confirmation message as directed in
the text, the reply goes to the postmaster of the smarthost for the
Microsoft SMTP Gateway.  Such replies are mysterious, because they
normally just contain the word OK, possibly followed by a confirmation
number.  There's little indication of what is going on.
 
As a LISTSERV postmaster myself, I understand why they do not want to
see bounce messages that they can do nothing about.  However, I am
suggesting to L-Soft, maker of LISTSERV, that they offer an option to
control the MAIL FROM value that LISTSERV uses.  This would allow sites
(such as us) that have both LISTSERV and Microsoft Mail, to change the
behavior to what it used to be.  I don't know yet if they plan do
implement this.
 
If you want to see how such messages look in your own mail system,
simply send any command (RELEASE is a good one) to
[log in to unmask] Then look closely at the reply.  The
address from the SMTP MAIL FROM may show up in a Return-Path header.