[Mailman-Users] Many users unsubscribed at once (not by me)

Keith Seyffarth weif at weif.net
Sun Dec 13 11:57:33 EST 2015

>> What is more likely is that a member of your list,
>> posts something to the list.  Then mailman tries to deliver the mail
>> to all the subscribers.  When it calls up some_site asking to deliver
>> mail to subscribers who have subscribed from accounts on some_site,
>> some_site says something to the effect of:
>> Drop dead.  We are protecting our users from receiving mail from
>> you!  No matter how many times you ask us to send mail to them,
>> we _won't_ because _we don't like you and your crappy mailing list_.
> So "some_site" in your example are all the mail servers around the world 
> which REFUSE to receive the posting(s) from my mailing list, and thus 
> sends an error message back to my list server's Mailman software.

In this particular example, some_site refers to the specific host the
receiving email addresses that were just automatically unsubscribed were
on, but it could be extrapolated to any site that is blocking your IP.

> And as these error messages on my list-server start piling up from 
> various mail servers around the world (i.e. "some_site") Mailman says 
> "OK, enough! The LIST-MEMBER sending those messages has to be banned as 
> messages from him won't receive a vast majority of the other list 
> members anyway, so I'll remove him so it won't happen again".

No, that isn't quite correct. Mailman sees that messages to
subscriber1 at some_site are bouncing and unsubscribed
subscriber1 at some_site, then sees that messages to subscriber2 at some_site
are bouncing and unsubscribes subscriber2 at some_site.

> Have I more or less understood it correctly?

The recipient addresses are the ones bouncing, and are therefore the
ones that are unsubscribed to stop the bouncing - and to protect your IP
addresses reputation by making it look less like you are a spammer.

<snip log location question and bounce notification question>

>> The usual reasons for disliking you are:
>> 1. We hate your IP, you have bad reputation with us, maybe you have been
>>     reported as a spammer someplace, or maybe you just send us a lot of
>>     mail and we don't like that.
> Again, this is the IP address of certain LIST-MEMBERS, right, and not my 
> list-server?

In this case, the IP of the list server.

> Does this also mean that the same receiving mail-servers will refuse 
> email sent from the same LIST-MEMBER, but sent directly (i.e. outside of 
> my mailing list)?

If this is the case, the receiving server (some_site) would likely
refuse any message sent from your list server, whether it was sent
through the mailing list or sent directly.

>> Mailman cannot do anything about this problem.  Talking to the site that
>> hates you can, if the site that hates you is willing to talk to you at
>> all about the problem.  Large sites, like aol typically do not.
> I don't have the capacity nor time to contact every single email 
> provider refusing to receive messages from certain list members.

They probably aren't refusing messages from certain list members, but
every message on your mailing list and possibly every message from your
mail server. Of course, this relies on this actually being the issue.

Another possibility is that a school or corporate mail server
administrator made a policy change and pushed new email addresses to
everyone, then after 4 or 6 or 8 months, or maybe a year of forwarding
old addresses to new addresses, deleted the old addresses so they are no
longer valid and these bounced generating the rash of unsubscribes. In
part, this is done by mailman so you do not look like a spammer who will
likely not bother removing invalid addresses from their address
lists. This is very similar to what has been going on with the
cable-provider-I-can't-remember-the-name-of to Bresnan to ComCast to
Charter changes in this part of the US over the last few years. All the
email addresses of the precursor to Bresnan have been deleted, and in
most areas all personal and many business Bresnan email addresses have
been deleted. Some users have had their email address forcibly changed
four times in four years...

>> 2.  We have a DMARC policy which is designed as follows:
>>      If mail comes in that originates from a user on one of our sites,
>>      and it doesn't come in on one of our servers, we will call this spam
>>      and refuse to deliver it.
>> The big offenders here are aol and yahoo.  This policy breaks every
>> mailing list on the planet.
>> A user on yahoo.com sends mail to a mailing list, and the list tries
>> to send it to all the subscribers, and when it tries for all the other
>> subscribers at yahoo.com, yahoo says, 'This mail that supposedly
>> came from user at yahoo.com, didn't come from one of our servers. Do
>> not deliver.'
> Ouch! So it won't accept the email because my list-server PASSES ON a 
> message, and that IP address is obviously not the same as that of the 
> LIST MEMBER posting that message in the first place?

Correct, if this is the issue causing your bounces.

<snipped questions about configuring 2.18>


from my mac to yours...

Keith Seyffarth
mailto:weif at weif.net
http://www.weif.net/ - Home of the First Tank Guide!
http://www.rpgcalendar.net/ - the Montana Role-Playing Calendar
http://www.miscon.org/ - Montana's Longest Running Science Fiction Convention

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