Quoting Rowland Penny via Dng (dng@???):

> It has happened again, my membership to this list has been disabled
> due to excessive bounces. I am fairly sure this isn't true, or I would
> have told by one of the Samba team list moderators.

dyne.org system administrators can investigate this matter, by
examining the /var/lib/mailman/logs/bounce* log files and
corresponding MTA log entries on lists.dyne.org -- to see when and why
and when the bounce scores for your Dng membership for rpenny@???
has increased, each time that has happened.

(My understanding is that the listadmins for Dng don't have the root
shell access required for such investigation, but of course other
Dyne.org core people do.)


Bounce processing in GNU Mailman is adjustable as to a number of
parameters used, both site-wide and per-mailing list, but here is how it
goes if using default values:

Each time for whatever reason the MTA detects non-delivery of a
subscriber's copy, subscriber's bounce score gets incremented by 1 if
parsing the MTA diagnostic appears to show a permanent failure, or by
0.5 if the MTA diagnostic appears to show a tempfail. Each day, if the
subscriber hasn't had a new bounce event within the past 7 days,
subscriber's bounce score resets to zero. Any day when the subscriber's
bounce score has risen to 5.0, subscription delivery gets disabled.
Once delivery has been disabled (which I gather is what you say was done
to your subscription), the subscriber then gets three 'Your membership
is disabled' autowarning mails, at intervals of a week, explaining what
happened and how to re-enable delivery. If the subscriber doesn't
respond, after a month, the subscriber gets unsubscribed.

I personally am a (friendly) outsider to dyne.org -- but administer
Mailman elsewhere, and so can explain in general terms how the mechanics
works. Here's example content from log file
/var/lib/mailman/logs/bounce on my own server, linuxmafia.com:


Dec 24 18:26:43 2018 (23567) <BounceRunner at 145300844> processing 1 queued bounces
Dec 24 18:26:43 2018 (23567) skeptic: aditya11@??? current bounce score: 2.0


Here is the matching MTA error:

# zgrep aditya11@??? /var/log/exim4/* | grep 2018-12-24 | grep "SMTP error"
/var/log/exim4/mainlog.10.gz:2018-12-24 18:26:42 1gbcPW-00033B-SM ** aditya11@??? R=dnslookup T=remote_smtp: SMTP error from remote mail server after MAIL FROM:<skeptic-bounces@???>: host al-ip4-mx-vip2.prodigy.net [144.160.235.144]: 550 5.7.1 Connections not accepted from servers without a valid sender domain.alph739 Fix reverse DNS for 198.144.195.186
#


(FWIW, I was somewhat startled to see the claim that my IP address, 198.144.195.186,
lacks valid DNS reverse pointing back to my mail domain, as that's just not the case:

$ dig -x 198.144.195.186 +short
linuxmafia.COM.
$

Someone at prodigy.net is screwing things up, it appears -- maybe
falsely triggering on the FQDN lettercase difference?

But otherwise, I hope the above properly illustrates how Dyne.org sysadmins could
research this matter.)