Help!  How can I prevent the multiple mailing problem that is documented below?
 
I am the owner of MINI-AIR, which has something over 18,000 subscribers.
We send out, typically, one item a month to everyone on the list.
(Only the editor is allowed to distribute items.)
 
WhenI sent out the last mailing, the list went into a loop.  Most or all of
the 18,000 subscribers received 6 copies before I found out it was happening.
I thereupon put the list on HOLD.
 
The problem seems to have been caused by something funny happening at
alaska.edu.  Every bounced message that people sent me (and a LOT of people
sent them to me) had the same error info (reproduced below).
 
So far all I have done is delete subscriber [log in to unmask],
and emailed the postmaster at alaska.edu to ask what's what there.
The postmaster, if there be such a person, has not answered any of my queries.
 
How can I prevent this problem from recurring?
I am by no means a LISTSERV expert, and would be very grateful for
some sound, simple advice.
 
By the way, in case it matters, version 1-8a of LISTSERV was installed here
just yesterday. The problem occurred with the previous version of the software.
I have not sent out anything since the problem occurred.
 
Here is the error info that was in every bounced message:
======================
Date:         Sun, 31 Jul 1994 12:47:36 -0800
Reply-To:     [log in to unmask]
Sender:       The Mini-Annals of Improbable Research <[log in to unmask]>
Comments:     Warning -- original Sender: tag was [log in to unmask]
From:         Marc Abrahams <[log in to unmask]>
 
[Non-Deliverable:  Non-deliverable loop detected and stopped][Non-Deliverable:
User JSTEW does not exist or has never logged on]
 
Reply-To: [log in to unmask]
 
[Non-Deliverable loop detected, message cannot be forwarded again][Non-Delivera
b
le:  User JSTEW does not exist or has never logged on]
 ==============================================================================
 
Sincerely and improbably, and in distress,
Marc Abrahams                                           ([log in to unmask])
Editor, The Annals of Improbable Research (AIR)
Former editor (1990-1994), The Journal of Irreproducible Results
 
 
Ps. Here's a suggestion made by one of our subscribers.
Does anyone have first-hand experience with "filter" and KNOW
for certain whether this would be a good thing to do?
The documentation was less than clear on the matter.
        ======================
        Have your listserv manager update your mini-air list definition
        headers with something like:
 
        * filter= also,*postmast*@*,*postmstr*@*
 
        This will / should help prevent such loops.
        ==============================