postfix connects to dovecot lmtp socket, but nothing is delivered

[Gerben Wierda]

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 at rna.nl
Jan 05 16:16:59 snape postfix/lmtp[126]: send attr recipient = sysbh at 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 at 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 at 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/>

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