postfix connects to dovecot lmtp socket, but nothing is delivered

[Aki Tuomi]

> On 05/01/2023 18:38 EET Gerben Wierda <gerben.wierda at rna.nl> wrote:
> 
> 
> 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 (http://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 (http://snape.rna.nl)[private/lmtp], delay=300, delays=0.02/0/300/0, dsn=4.4.2, status=deferred (conversation with snape.rna.nl (http://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 (http://rna.nl) id C71B3D1262
> Jan 05 16:16:59 snape postfix/lmtp[126]: match_list_match: rna.nl (http://rna.nl): no match
> Jan 05 16:16:59 snape postfix/lmtp[126]: flush_add: site rna.nl (http://rna.nl) id C71B3D1262 status 4
> Jan 05 16:16:59 snape postfix/lmtp[126]: deliver_request_final: send: "conversation with snape.rna.nl (http://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 (http://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))


Maybe selinux or apparmor? Also, using TCP instead of unix socket is not a bad idea to try out.

Aki