[Mailman-Users] Bounces threshold never reached

Mark Sapiro mark at msapiro.net
Mon Jun 6 23:01:21 EDT 2016

On 06/06/2016 01:48 AM, Kala Balik wrote:
> two weeks ago we sent out a mailing through our six new mailman lists
> with roughly 6.000 subscribers. We expected to get a number of bounces,
> however, while the bounces log shows that about 600 subscribers did get
> a bounce score of 1.0 or 2.0, not a single address reached the threshold
> of 5.0 (or anything above 2.0) and, consequently, the admins did not get
> notice about any disables or removals.

That's exactly what I would expect.

> Here is my bouncing configuration:
> bounce_processing: yes
> bounce_score_threshold: 5.0
> bounce_info_stale_after: 7
> bounce_you_are_disabled_warnings: 3
> bounce_you_are_disabled_warnings_interval: 7
> bounce_unrecognized_goes_to_list_owner: yes
> bounce_notify_owner_on_disable: yes
> bounce_notify_owner_on_removal: yes

Starting with Mailman 2.1.19, there is also a
bounce_notify_owner_on_bounce_increment  setting which will notify the
owner any time the score is incremented.

>>From reading the information in the web interface my understanding of
> the bounces processing is that for "bad" (i.e. unreachable) addresses
> the bounces score increases EVERYDAY by 1.0 (hard bounces) or .5 (soft
> bounces).


The score is incremented by 1.0 on the first received bounce of the day.
On a day that there are no posts and hence no bounces, the score isn't

If there are no bounces for bounce_info_stale_after (in your case 7)
days, the next bounce will reset the score to 1.0.

There aren't actually any 'soft' bounces so the score never increments
by 0.5.

Since my bounces log only displays whole numbers (either 1.0
> or 2.0) I assume that most of my bounces were hard bounces (scoring 1.0
> each). Therefore, constantly unreachable addresses should have reached
> the threshold of 5.0 after 5 days.

After 5 days on which new bounces were recorded. See above.

> Yet my log reads as if the email providers of most (about 500)
> subscribers with bounces were unreachable on the day of the mailing
> (kind of plausible), while the others (about 100) were "down" for two
> days and then online again (not very plausible). Providers may be
> unreliable sometimes, but not that unreliable. And our address base may
> be good, but not that good (no permanent bouncees at all - or am I
> misunderstanding the concept of permanence here - and, consequently, no
> automatic unsubscribes at all).

Your misunderstanding is that Mailman has no way to determine if a
bouncing address will bounce the next day without sending a post and
having it bounce. No post = no bounce for that day = no score increment.

> What am I missing here? And how do I "repair" bounce processing and
> automatic unsubscribe?

It's working as intended. If yo actually want member's delivery disabled
after one or two bounces, set  bounce_score_threshold to 1 or 2.

In general your settings which are the default are appropriate for lists
which receive several posts a week or at least never more than 7 days
between posts. If your list is lower volume than that, you may want to
decrease bounce_score_threshold and increase bounce_info_stale_after.

Note that once a member's delivery is disabled by bounce_score_threshold
being reached, Mailman no longer looks for bounces for that member and
the bounce_you_are_disabled_warnings and
bounce_you_are_disabled_warnings_interval settings take over.

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

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