[MM3-users] Postfix SMTP REJECT non-subscribers

Hi,

With Mailman 2, I have configuration and scripts to reject non-members from posting to lists _during the SMTP connection_. This is better than bouncing (no backscatter), better than discarding messages (the user finds out) and better than moderation (spammy messages aren't forwarded to external email systems).

The configuration and scripts are described here: https://code.launchpad.net/~jimpop/mailman/check_subscriber

Is anything like this built-in to Mailman 3?  I cannot find it in Gitlab.

Thanks,

Matt