I am setting up a new server combination (postfix + dovecot). dovecot's auth service works for postfix. Just lmtp does not and I need to find out why. I don't see anything in the dovecot logging, but I see this on the postfix side (debug)

Jan 05 16:11:59 snape postfix/lmtp[127]: connection established Jan 05 16:11:59 snape postfix/lmtp[127]: master_notify: status 0 Jan 05 16:11:59 snape postfix/lmtp[127]: deliver_request_initial: send initial response Jan 05 16:11:59 snape postfix/lmtp[127]: send attr protocol = delivery_request_protocol Jan 05 16:16:59 snape postfix/lmtp[126]: smtp_get: timeout Jan 05 16:16:59 snape postfix/lmtp[126]: connect to subsystem private/defer Jan 05 16:16:59 snape postfix/lmtp[126]: private/defer socket: wanted attribute: protocol Jan 05 16:16:59 snape postfix/lmtp[126]: input attribute name: protocol Jan 05 16:16:59 snape postfix/lmtp[126]: input attribute value: delivery_status_protocol Jan 05 16:16:59 snape postfix/lmtp[126]: private/defer socket: wanted attribute: (list terminator) Jan 05 16:16:59 snape postfix/lmtp[126]: input attribute name: (end) Jan 05 16:16:59 snape postfix/lmtp[126]: send attr nrequest = 0 Jan 05 16:16:59 snape postfix/lmtp[126]: send attr flags = 0 Jan 05 16:16:59 snape postfix/lmtp[126]: send attr queue_id = C71B3D1262 Jan 05 16:16:59 snape postfix/lmtp[126]: send attr original_recipient = sysbh@rna.nl Jan 05 16:16:59 snape postfix/lmtp[126]: send attr recipient = sysbh@rna.nl Jan 05 16:16:59 snape postfix/lmtp[126]: send attr offset = 18446744073709551615 Jan 05 16:16:59 snape postfix/lmtp[126]: send attr dsn_orig_rcpt = rfc822;sysbh@rna.nl Jan 05 16:16:59 snape postfix/lmtp[126]: send attr notify_flags = 0 Jan 05 16:16:59 snape postfix/lmtp[126]: send attr status = 4.4.2 Jan 05 16:16:59 snape postfix/lmtp[126]: send attr diag_type = Jan 05 16:16:59 snape postfix/lmtp[126]: send attr diag_text = Jan 05 16:16:59 snape postfix/lmtp[126]: send attr mta_type = Jan 05 16:16:59 snape postfix/lmtp[126]: send attr mta_mname = Jan 05 16:16:59 snape postfix/lmtp[126]: send attr action = delayed Jan 05 16:16:59 snape postfix/lmtp[126]: send attr reason = conversation with snape.rna.nl[private/lmtp] timed out while receiving the initial server greeting Jan 05 16:16:59 snape postfix/lmtp[126]: private/defer socket: wanted attribute: status Jan 05 16:16:59 snape postfix/lmtp[126]: input attribute name: status Jan 05 16:16:59 snape postfix/lmtp[126]: input attribute value: 0 Jan 05 16:16:59 snape postfix/lmtp[126]: private/defer socket: wanted attribute: (list terminator) Jan 05 16:16:59 snape postfix/lmtp[126]: input attribute name: (end) Jan 05 16:16:59 snape postfix/lmtp[126]: C71B3D1262: to=sysbh@rna.nl, relay=snape.rna.nl[private/lmtp], delay=300, delays=0.02/0/300/0, dsn=4.4.2, status=deferred (conversation with snape.rna.nl[private/lmtp] timed out while receiving the initial server greeting) Jan 05 16:16:59 snape postfix/lmtp[126]: flush_add: site rna.nl id C71B3D1262 Jan 05 16:16:59 snape postfix/lmtp[126]: match_list_match: rna.nl: no match Jan 05 16:16:59 snape postfix/lmtp[126]: flush_add: site rna.nl id C71B3D1262 status 4 Jan 05 16:16:59 snape postfix/lmtp[126]: deliver_request_final: send: "conversation with snape.rna.nl[private/lmtp] timed out while receiving the initial server greeting" -1 Jan 05 16:16:59 snape postfix/lmtp[126]: send attr status = 4.4.2 Jan 05 16:16:59 snape postfix/lmtp[126]: send attr diag_type = Jan 05 16:16:59 snape postfix/lmtp[126]: send attr diag_text = Jan 05 16:16:59 snape postfix/lmtp[126]: send attr mta_type = Jan 05 16:16:59 snape postfix/lmtp[127]: master_notify: status 1 Jan 05 16:16:59 snape postfix/lmtp[126]: send attr mta_mname = Jan 05 16:16:59 snape postfix/lmtp[127]: connection closed Jan 05 16:16:59 snape postfix/lmtp[126]: send attr action = Jan 05 16:16:59 snape postfix/lmtp[126]: send attr reason = conversation with snape.rna.nl[private/lmtp] timed out while receiving the initial server greeting Jan 05 16:16:59 snape postfix/lmtp[126]: send attr status = 4294967295 Jan 05 16:16:59 snape postfix/lmtp[126]: master_notify: status 1 Jan 05 16:16:59 snape postfix/lmtp[126]: connection closed

It seems dovecot doesn't react to whatever postfix is doing on the socket. Another possibility is that the socket doesn't really work and dovecot never gets a connection request. How can I debug this?

Might I test if the socket is the problem by running lmtp on the dovecot side on TCP on 127.0.0.1 and have postfix use that? Just to see if it works? If so, how do I tell postfix to do that? In dovecot I have added the tcp:

service lmtp { inet_listener lmtp { address = 127.0.0.1 port = 24 } unix_listener /var/spool/postfix/private/lmtp { mode = 0660 user = postfix group = postfix } } service lmtp { executable = lmtp -L } protocol lmtp { info_log_path = /var/log/mail/dovecot-lmtp.log }

Any other tips?

Gerben Wierda (LinkedIn https://www.linkedin.com/in/gerbenwierda) R&A IT Strategy https://ea.rna.nl/ (main site) Book: Chess and the Art of Enterprise Architecture https://ea.rna.nl/the-book/ Book: Mastering ArchiMate https://ea.rna.nl/the-book-edition-iii/