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man pages section 8: System Administration Commands

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Updated: Wednesday, July 27, 2022

qmqpd (8)


qmqpd - Postfix QMQP server


qmqpd [generic Postfix daemon options]


QMQPD(8)                    System Manager's Manual                   QMQPD(8)

       qmqpd - Postfix QMQP server

       qmqpd [generic Postfix daemon options]

       The Postfix QMQP server receives one message per connection.  Each mes-
       sage is piped through the cleanup(8) daemon, and  is  placed  into  the
       incoming queue as one single queue file.  The program expects to be run
       from the master(8) process manager.

       The QMQP server implements one access policy:  only  explicitly  autho-
       rized client hosts are allowed to use the service.

       The  QMQP  server  is  moderately  security-sensitive. It talks to QMQP
       clients and to DNS servers on the network. The QMQP server can  be  run
       chrooted at fixed low privilege.

       Problems and transactions are logged to syslogd(8).

       The  QMQP protocol provides only one server reply per message delivery.
       It is therefore not possible to reject individual recipients.

       The QMQP protocol requires the server to  receive  the  entire  message
       before  replying. If a message is malformed, or if any netstring compo-
       nent is longer than acceptable, Postfix replies immediately and  closes
       the connection. It is left up to the client to handle the situation.

       Changes  to  main.cf are picked up automatically, as qmqpd(8) processes
       run for only a limited amount of time. Use the command "postfix reload"
       to speed up a change.

       The  text  below provides only a parameter summary. See postconf(5) for
       more details including examples.

       content_filter (empty)
              After the message is queued, send  the  entire  message  to  the
              specified transport:destination.

       receive_override_options (empty)
              Enable or disable recipient validation, built-in content filter-
              ing, or address mapping.

       Preliminary SMTPUTF8 support is introduced with Postfix 3.0.

       smtputf8_enable (yes)
              Enable preliminary SMTPUTF8 support for the protocols  described
              in RFC 6531..6533.

       smtputf8_autodetect_classes (sendmail, verify)
              Detect  that  a message requires SMTPUTF8 support for the speci-
              fied mail origin classes.

       Available in Postfix version 3.2 and later:

       enable_idna2003_compatibility (no)
              Enable  'transitional'  compatibility   between   IDNA2003   and
              IDNA2008,  when  converting UTF-8 domain names to/from the ASCII
              form that is used for DNS lookups.

       line_length_limit (2048)
              Upon input, long lines are chopped up into  pieces  of  at  most
              this length; upon delivery, long lines are reconstructed.

       hopcount_limit (50)
              The maximal number of Received:  message headers that is allowed
              in the primary message headers.

       message_size_limit (10240000)
              The maximal size in  bytes  of  a  message,  including  envelope

       qmqpd_timeout (300s)
              The  time  limit  for  sending or receiving information over the

       debug_peer_level (2)
              The increment in verbose logging level when a remote  client  or
              server matches a pattern in the debug_peer_list parameter.

       debug_peer_list (empty)
              Optional  list  of  remote  client or server hostname or network
              address  patterns  that  cause  the  verbose  logging  level  to
              increase by the amount specified in $debug_peer_level.

       soft_bounce (no)
              Safety  net to keep mail queued that would otherwise be returned
              to the sender.

       qmqpd_error_delay (1s)
              How long the Postfix QMQP server will  pause  before  sending  a
              negative reply to the remote QMQP client.

       config_directory (see 'postconf -d' output)
              The  default  location of the Postfix main.cf and master.cf con-
              figuration files.

       daemon_timeout (18000s)
              How much time a Postfix daemon process  may  take  to  handle  a
              request before it is terminated by a built-in watchdog timer.

       ipc_timeout (3600s)
              The  time  limit  for  sending  or receiving information over an
              internal communication channel.

       max_idle (100s)
              The maximum amount of time that an idle Postfix  daemon  process
              waits for an incoming connection before terminating voluntarily.

       max_use (100)
              The maximal number of incoming connections that a Postfix daemon
              process will service before terminating voluntarily.

       process_id (read-only)
              The process ID of a Postfix command or daemon process.

       process_name (read-only)
              The process name of a Postfix command or daemon process.

       qmqpd_authorized_clients (empty)
              What remote QMQP clients are allowed to connect to  the  Postfix
              QMQP server port.

       queue_directory (see 'postconf -d' output)
              The location of the Postfix top-level queue directory.

       syslog_facility (mail)
              The syslog facility of Postfix logging.

       syslog_name (see 'postconf -d' output)
              A  prefix  that  is  prepended  to  the  process  name in syslog
              records, so that, for example, "smtpd" becomes "prefix/smtpd".

       verp_delimiter_filter (-=+)
              The characters Postfix accepts as VERP delimiter  characters  on
              the Postfix sendmail(1) command line and in SMTP commands.

       Available in Postfix version 2.5 and later:

       qmqpd_client_port_logging (no)
              Enable logging of the remote QMQP client port in addition to the
              hostname and IP address.

       See attributes(7) for descriptions of the following attributes:

       |ATTRIBUTE TYPE |       ATTRIBUTE VALUE        |
       |Availability   | service/network/smtp/postfix |
       |Stability      | Volatile                     |

       http://cr.yp.to/proto/qmqp.html, QMQP protocol
       cleanup(8), message canonicalization
       master(8), process manager
       syslogd(8), system logging

       Use "postconf readme_directory" or "postconf html_directory" to  locate
       this information.
       QMQP_README, Postfix ezmlm-idx howto.

       The Secure Mailer license must be distributed with this software.

       The qmqpd service was introduced with Postfix version 1.1.

       Wietse Venema
       IBM T.J. Watson Research
       P.O. Box 704
       Yorktown Heights, NY 10598, USA

       Wietse Venema
       Google, Inc.
       111 8th Avenue
       New York, NY 10011, USA

       Source code for open source software components in Oracle Solaris can
       be found at https://www.oracle.com/downloads/opensource/solaris-source-

       This software was built from source available at
       https://github.com/oracle/solaris-userland.  The original community
       source was downloaded from  https://archive.mgm51.com/mirrors/postfix-

       Further information about this software can be found on the open source
       community website at http://www.postfix.org.