[MM3-users] Re: Cannot start lmtp runner due to error while attempting to bind on address ('127.0.0.1', 8024): address already in use

actionmystique@gmail.com writes:

Dovecot is the LMTP server (https://doc.dovecot.org/configuration_manual/protocols/lmtp_server/) listening on port 8024. I thought that lmtp_port was precisely the port where to contact the LMTP server, as described in the comments (cf. first post).

• Are those comments wrong?

In Mailman documentation, Mailman's LMTP server is *the* LMTP server. Mailman wouldn't send *to* an LMTP server, it would send to the MTA's "submission" port or to the SMTP port.

• Is mailman trying to act as a LMTP server instead?

Yes.

• If so, wouldn't there be an issue with 2 LMTP servers if I choose another port number for lmtp_port?

No. Apparently Dovecot made the same architectural decision that Mailman did: "I want to receive incoming mail via LMTP because all the MTAs I'm willing to talk to can do it that way so I don't have to worry about pipes and configs and sockets, oh my!" Both want to receive via LMTP. So it has to be different ports. Only the MTA and Mailman need to know Mailman's port, and ditto for MTA + Dovecot. Ie:

                   LMTP                  SMTP
                 +-----> Mailman @ 9024 -----> subscribers
      SMTP       |           (or whereever)

Internet -----> MTA -+ | LMTP IMAP +-----> Dovecot @ 8024 -----> local users

or whatever.

(note to me: needs to be in dox)

Steve