[MM3-users] Re: mailqueue shows bounces for emails that are not on the mailing list

Paul Ssekamatte via Mailman-users writes:

1. strangely so far i only see Yahoo domain in the spam
2. I use Postfix as the MTA
3. The MTA only relays for a specific list of senders
4. It is a production mail server so we have most of those controls in place i.e DKIM, SPF
5. I have not identified any suspicious logins, the bad actors must be using the subscription option on my mailing lists info page

OK, I would say the chances are that Mark is right. There is another channel that could cause the same effect, which is mail subscriptions to $LIST-join@$YOUR.DOMAIN (also $LIST-subscribe and $LIST-request variants on many systems).

Steve

-- GNU Mailman consultant (installation, migration, customization) Sirius Open Source https://www.siriusopensource.com/ Software systems consulting in Europe, North America, and Japan