I am running a local Postfix server. it runs fine for submission on port 587. I use this as it actually gets a lower bounce rate than Amazon SES and various other commercial SMTP providers that I have tried (believe it or not).
As much of the advice on this forum advises, I used mail-receiver for inbound on port 25. Works fine. But, bounces using the VERP regex do no get through. I cannot solve this.
So I turned that off and spent a lot of effort to install Dovecot and set up POP3 in conjunction with Postfix.
My domain is [something].space. and the user for inbound for the General category is [something]@[something].space. I now have a local mailbox for that user which Discourse polls via POP3. [Better to hide the real names to avoid spam I think.] So there is just that one user for inbound.
But bounces come back to the VERP regex you have to set. And they canāt be delivered anywhere because there is no such user ārepliesā. Hereās the mail.log entry for an example of mail purposely sent to a non-existent address:
[something] postfix/local[218189]: 068272FEA4F: to=<replies+verp-7d39e178a71b450220c072608e269da7@[something].space>, relay=local, delay=0.01, delays=0/0/0/0, dsn=5.1.1, status=bounced (unknown user: ārepliesā)
[Domain again edited for security.]
Help would be very much appreciated. Please donāt ask me to revert to mail-receiver, as that had exactly the same issue, and I would prefer to use Dovecot/Postfix at this stage. I am sure others have a similar setup with success.
Herre is the VERP setting:
replies+%{reply_key}@.space