[Mailman-Users] Bounce message confusion

Mark Sapiro msapiro at value.net
Fri Nov 18 21:23:17 CET 2005

Robin Rowe wrote:

>After my Mailman list exceeded 500 subscribers I started getting 
>complaints from subscribers of spurious bounce messages. There's nothing 
>wrong with their email addresses. I can't seem to turn these annoying 
>bounce messages off in Mailman. What settings should I try?
>At my ISP the SMTP message rate seems to be throttled to 500/hour, and 
>that may be what's triggering the bounce problem to begin with.

Stephen J. Turnbull wrote:
>In fact, the relevant feature (queueing the mail for later delivery
>when the service is available) is already built into the MTA.  Your
>ISP has basically put a policy in place that says "you can't use this
>feature; just behave yourself and everything will work."  It's not a
>mailing list manager's purpose to help you work around those
>restrictions.  You really need to get in touch with your ISP's support

I have just one thing to add. I think Robin is correct that the
outgoing MTA is refusing the additional recipients over 500 and that
is resulting in the bounces. I have heard other reports of ISP's
offering Mailman service and effectively restricting Mailman to 500
(or some number) of recipients per hour. I think this is ridiculous,
deceptive and borders on fraudulent. If you can't make the ISP see
this, find another Mailman host with rational policies.

Here, courtesy of Brad Knowles' mmdsr script is one day's fairly
typical activity from a small installation with only a few lists.

Hourly Summary of Messages Sent
       3 00:00-00:59
       0 01:00-01:59
       6 02:00-02:59
       0 03:00-03:59
       0 04:00-04:59
       3 05:00-05:59
       3 06:00-06:59
     183 07:00-07:59
       5 08:00-08:59
     235 09:00-09:59
     656 10:00-10:59
     718 11:00-11:59
     468 12:00-12:59
     542 13:00-13:59
     243 14:00-14:59
     430 15:00-15:59
      68 16:00-16:59
     117 17:00-17:59
     429 18:00-18:59
     423 19:00-19:59
     234 20:00-20:59
     304 21:00-21:59
     715 22:00-22:59
    1086 23:00-23:59

As you can see, restricting Mailman to 500 messages per hour would not
be satisfactory. Even if you could throttle Mailman to send <500 per
hour, it would only take a small increase to create unrecoverable

Mark Sapiro <msapiro at value.net>       The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan

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