[MlMt] List membership disabled -- excessive bounces?

[Sebastian Hagedorn]

On 19 May 2025, at 10:30, Benny Kjær Nielsen wrote:

> On 18 May 2025, at 22:37, Devyn Osborne wrote:
>
>> Today I received the following message from the mailing list (including instructions to reenable, which I did). I don’t understand what caused this though… is my Gmail address bouncing messages from the list?
>
> Yes, the list has been trying to send you emails which have been rejected by Gmail. According to Google, it's some kind of DKIM related issue. It seems this happened for all Gmail-users on the mailing list.
>
>> And/or what can I do to avoid further issues?
>
> To be honest, I'm not sure. If anything can be changed then it's probably only me who can do it.
>
> I have not made any changes on the server recently. I've got DKIM/SPF/DMARC configured and it appears to have worked for a long time, but I'm really not an expert on the details. I just know that every few months Google, Apple, or Microsoft will have some reason to start rejecting all emails from the list. It's for different reasons and some times I need to use a web-form somewhere to make it work again. It's impossible to get a human being to actually tell me what the problem is :)
>
> It's possible that there's something I could improve/fix at my end (server or DNS), but I don't really think that these blockages will stop no matter what I do.
>
> If possible, just don't use your Gmail/iCloud/Office365 email address when subscribing to a mailing list.

As someone who runs a large Mailman server as my day job: Benny has to use Mailman’s DMARC handling. We have opted to use the following setting for most of our lists:

Privacy options -> Sender filter -> Action to take when anyone posts to the list from a domain with a DMARC Reject/Quarantine Policy: Wrap message

You could also use "Munge from", but I personally prefer to leave the message as is.
-- 
   .:.Sebastian Hagedorn - Weyertal 121 (Gebäude 133), Zimmer 2.13.:.
                .:.IT Center University of Cologne (ITCC)).:.
  .:.Universität zu Köln / Cologne University - ✆ +49-221-470-89578.:.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 3981 bytes
Desc: S/MIME digital signature
URL: <http://lists.freron.com/pipermail/mailmate/attachments/20250519/a0616184/attachment-0001.bin>