On 05-18-2021 12:36 pm, Jaroslaw Rafa wrote: If Postfix on server X is only for submission, then how does Postfix on server Y deliver mail to server X?
It doesn't because as you said, server X is only for submission. Nothing should ever be delivered to X. Server Y is the destination and Y should deliver to maildir. On a two server setup this is easy by just removing the virtual_mailbox_domains map on server X. But on a single server setup trying to get the same behavior, thus far not possible... without Victor's suggestion of multi-instance setup.
And to the rest of your suggestions, the way im trying to set this up is one server is just for accepting email smtp:25 and it should be the only server accepting email via only smtp:25. I don't want it to accept submissions, relays, etc.
The 2nd server is for dealing with users. It will allow them to check their email via dovecot/imap and it will allow them to send emails from their client, hence the postfix submission. As i said the only reason postfix is even on that server is because dovecot built in submission does not validate authenticated user against From: address and will allow spoofing. This is why i need to have postfix to accept submissions on that imap server. But it has no business directly delivering mail to local maildir.
This behavior is solved by on the imap/postfix server removing virtual_mailbox_domains from main.cf
All of this long winded back and forth is i was "hoping" to find a solution that would *also* work for a single server setup. I understand now that postfix isn't built that way.
And i know you all keep politely telling me im crazy for not understanding postfix wants to deliver to user's mailboxes. I get that. Not knowing the inner workings of postfix, from a logical point of view, submission isn't smtp:25, it has its own service spawn, it works on its own port, so it didn't seem crazy to expect it to be able to behave differently than smtp:25. I at first didn't understand that it has to use the same setting values that smtp:25 uses. I mean, logically that being the case, what is the point of having a separate submission on port 587 when smtp:25 could just "answer the call" if all of the settings are the same between the two?
If you have read this far, i have my answer now, postfix can't do what i want how i think. The recommended solution by Victor is to use multi-instance.
