phpman > man > oqmgr(8postfix)

OQMGR(8postfix)                                                                      OQMGR(8postfix)



NAME
       oqmgr - old Postfix queue manager

SYNOPSIS
       oqmgr [generic Postfix daemon options]

DESCRIPTION
       The  oqmgr(8)  daemon  awaits  the arrival of incoming mail and arranges for its delivery via
       Postfix delivery processes.  The actual mail routing strategy is delegated to the trivial-re‐‐
       write(8) daemon.  This program expects to be run from the master(8) process manager.

       Mail addressed to the local double-bounce address is logged and discarded.  This stops poten‐
       tial loops caused by undeliverable bounce notifications.

MAIL QUEUES
       The oqmgr(8) daemon maintains the following queues:

       incoming
              Inbound mail from the network, or mail picked up by the local pickup(8) agent from the
              maildrop directory.

       active Messages that the queue manager has opened for delivery. Only a limited number of mes‐
              sages is allowed to enter the active queue (leaky bucket strategy, for a fixed  deliv‐
              ery rate).

       deferred
              Mail  that could not be delivered upon the first attempt. The queue manager implements
              exponential backoff by doubling the time between delivery attempts.

       corrupt
              Unreadable or damaged queue files are moved here for inspection.

       hold   Messages that are kept "on hold" are kept here until someone sets them free.

DELIVERY STATUS REPORTS
       The oqmgr(8) daemon keeps an eye on per-message delivery status reports in the following  di‐
       rectories. Each status report file has the same name as the corresponding message file:

       bounce Per-recipient  status  information  about  why mail is bounced.  These files are main‐
              tained by the bounce(8) daemon.

       defer  Per-recipient status information about why mail is delayed.   These  files  are  main‐
              tained by the defer(8) daemon.

       trace  Per-recipient status information as requested with the Postfix "sendmail -v" or "send‐‐
              mail -bv" command.  These files are maintained by the trace(8) daemon.

       The oqmgr(8) daemon is responsible for asking the bounce(8), defer(8) or trace(8) daemons  to
       send delivery reports.

STRATEGIES
       The  queue  manager implements a variety of strategies for either opening queue files (input)
       or for message delivery (output).

       leaky bucket
              This strategy limits the number of messages in the active queue and prevents the queue
              manager from running out of memory under heavy load.

       fairness
              When  the active queue has room, the queue manager takes one message from the incoming
              queue and one from the deferred queue. This prevents a large mail backlog from  block‐
              ing the delivery of new mail.

       slow start
              This  strategy eliminates "thundering herd" problems by slowly adjusting the number of
              parallel deliveries to the same destination.

       round robin
              The queue manager sorts delivery requests by destination.  Round-robin selection  pre‐
              vents one destination from dominating deliveries to other destinations.

       exponential backoff
              Mail  that  cannot be delivered upon the first attempt is deferred.  The time interval
              between delivery attempts is doubled after each attempt.

       destination status cache
              The queue manager avoids unnecessary delivery attempts by  maintaining  a  short-term,
              in-memory list of unreachable destinations.

TRIGGERS
       On an idle system, the queue manager waits for the arrival of trigger events, or it waits for
       a timer to go off. A trigger is a one-byte message.  Depending on the message  received,  the
       queue  manager performs one of the following actions (the message is followed by the symbolic
       constant used internally by the software):

       D (QMGR_REQ_SCAN_DEFERRED)
              Start a deferred queue scan.  If a deferred queue scan is already  in  progress,  that
              scan will be restarted as soon as it finishes.

       I (QMGR_REQ_SCAN_INCOMING)
              Start  an  incoming queue scan. If an incoming queue scan is already in progress, that
              scan will be restarted as soon as it finishes.

       A (QMGR_REQ_SCAN_ALL)
              Ignore deferred queue file time stamps. The request affects the  next  deferred  queue
              scan.

       F (QMGR_REQ_FLUSH_DEAD)
              Purge all information about dead transports and destinations.

       W (TRIGGER_REQ_WAKEUP)
              Wakeup  call, This is used by the master server to instantiate servers that should not
              go away forever. The action is to start an incoming queue scan.

       The oqmgr(8) daemon reads an entire buffer worth of triggers.  Multiple identical trigger re‐
       quests  are collapsed into one, and trigger requests are sorted so that A and F precede D and
       I. Thus, in order to force a deferred queue run, one would request A F D; in order to  notify
       the queue manager of the arrival of new mail one would request I.

STANDARDS
       RFC 3463 (Enhanced status codes)
       RFC 3464 (Delivery status notifications)

SECURITY
       The  oqmgr(8)  daemon  is not security sensitive. It reads single-character messages from un‐
       trusted local users, and thus may be susceptible to denial of service attacks.  The  oqmgr(8)
       daemon  does not talk to the outside world, and it can be run at fixed low privilege in a ch‐
       rooted environment.

DIAGNOSTICS
       Problems and transactions are logged to the syslogd(8) or postlogd(8) daemon.  Corrupted mes‐
       sage files are saved to the corrupt queue for further inspection.

       Depending  on  the  setting  of  the  notify_classes parameter, the postmaster is notified of
       bounces and of other trouble.

BUGS
       A single queue manager process has to compete for disk access with  multiple  front-end  pro‐
       cesses  such as cleanup(8). A sudden burst of inbound mail can negatively impact outbound de‐
       livery rates.

CONFIGURATION PARAMETERS
       Changes to main.cf are not picked up automatically, as oqmgr(8) is a persistent process.  Use
       the command "postfix reload" after a configuration change.

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

       In the text below, transport is the first field in a master.cf entry.

COMPATIBILITY CONTROLS
       Available before Postfix version 2.5:

       allow_min_user (no)
              Allow a sender or recipient address to have `-' as the first character.

       Available with Postfix version 2.7 and later:

       default_filter_nexthop (empty)
              When a content_filter or FILTER request specifies no  explicit  next-hop  destination,
              use  $default_filter_nexthop  instead; when that value is empty, use the domain in the
              recipient address.

ACTIVE QUEUE CONTROLS
       qmgr_clog_warn_time (300s)
              The minimal delay between warnings that a specific  destination  is  clogging  up  the
              Postfix active queue.

       qmgr_message_active_limit (20000)
              The maximal number of messages in the active queue.

       qmgr_message_recipient_limit (20000)
              The  maximal number of recipients held in memory by the Postfix queue manager, and the
              maximal size of the short-term, in-memory "dead" destination status cache.

DELIVERY CONCURRENCY CONTROLS
       qmgr_fudge_factor (100)
              Obsolete feature: the percentage of delivery resources that a busy  mail  system  will
              use up for delivery of a large mailing  list message.

       initial_destination_concurrency (5)
              The initial per-destination concurrency level for parallel delivery to the same desti‐
              nation.

       default_destination_concurrency_limit (20)
              The default maximal number of parallel deliveries to the same destination.

       transport_destination_concurrency_limit ($default_destination_concurrency_limit)
              A transport-specific override for the default_destination_concurrency_limit  parameter
              value, where transport is the master.cf name of the message delivery transport.

       Available in Postfix version 2.5 and later:

       transport_initial_destination_concurrency ($initial_destination_concurrency)
              A transport-specific override for the initial_destination_concurrency parameter value,
              where transport is the master.cf name of the message delivery transport.

       default_destination_concurrency_failed_cohort_limit (1)
              How many pseudo-cohorts must suffer connection or handshake failure before a  specific
              destination is considered unavailable (and further delivery is suspended).

       transport_destination_concurrency_failed_cohort_limit           ($default_destination_concur‐‐
       rency_failed_cohort_limit)
              A  transport-specific  override  for  the   default_destination_concurrency_failed_co‐
              hort_limit  parameter  value, where transport is the master.cf name of the message de‐
              livery transport.

       default_destination_concurrency_negative_feedback (1)
              The per-destination amount of delivery concurrency negative feedback, after a delivery
              completes with a connection or handshake failure.

       transport_destination_concurrency_negative_feedback   ($default_destination_concurrency_nega‐‐
       tive_feedback)
              A transport-specific override for  the  default_destination_concurrency_negative_feed‐
              back  parameter  value,  where transport is the master.cf name of the message delivery
              transport.

       default_destination_concurrency_positive_feedback (1)
              The per-destination amount of delivery concurrency positive feedback, after a delivery
              completes without connection or handshake failure.

       transport_destination_concurrency_positive_feedback   ($default_destination_concurrency_posi‐‐
       tive_feedback)
              A transport-specific override for  the  default_destination_concurrency_positive_feed‐
              back  parameter  value,  where transport is the master.cf name of the message delivery
              transport.

       destination_concurrency_feedback_debug (no)
              Make the queue manager's feedback algorithm verbose for performance analysis purposes.

RECIPIENT SCHEDULING CONTROLS
       default_destination_recipient_limit (50)
              The default maximal number of recipients per message delivery.

       transport_destination_recipient_limit ($default_destination_recipient_limit)
              A transport-specific override for  the  default_destination_recipient_limit  parameter
              value, where transport is the master.cf name of the message delivery transport.

OTHER RESOURCE AND RATE CONTROLS
       minimal_backoff_time (300s)
              The  minimal time between attempts to deliver a deferred message; prior to Postfix 2.4
              the default value was 1000s.

       maximal_backoff_time (4000s)
              The maximal time between attempts to deliver a deferred message.

       maximal_queue_lifetime (5d)
              Consider a message as undeliverable, when delivery fails with a temporary  error,  and
              the time in the queue has reached the maximal_queue_lifetime limit.

       queue_run_delay (300s)
              The  time  between deferred queue scans by the queue manager; prior to Postfix 2.4 the
              default value was 1000s.

       transport_retry_time (60s)
              The time between attempts by the Postfix queue manager  to  contact  a  malfunctioning
              message delivery transport.

       Available in Postfix version 2.1 and later:

       bounce_queue_lifetime (5d)
              Consider  a  bounce message as undeliverable, when delivery fails with a temporary er‐
              ror, and the time in the queue has reached the bounce_queue_lifetime limit.

       Available in Postfix version 2.5 and later:

       default_destination_rate_delay (0s)
              The default amount of delay that is inserted between individual message deliveries  to
              the same destination and over the same message delivery transport.

       transport_destination_rate_delay ($default_destination_rate_delay)
              A  transport-specific override for the default_destination_rate_delay parameter value,
              where transport is the master.cf name of the message delivery transport.

       Available in Postfix version 3.1 and later:

       default_transport_rate_delay (0s)
              The default amount of delay that is inserted  between  individual  message  deliveries
              over the same message delivery transport, regardless of destination.

       transport_transport_rate_delay ($default_transport_rate_delay)
              A  transport-specific  override  for the default_transport_rate_delay parameter value,
              where the initial transport in the parameter name is the master.cf name of the message
              delivery transport.

SAFETY CONTROLS
       qmgr_daemon_timeout (1000s)
              How  much  time a Postfix queue manager process may take to handle a request before it
              is terminated by a built-in watchdog timer.

       qmgr_ipc_timeout (60s)
              The time limit for the queue manager to send or receive information over  an  internal
              communication channel.

       Available in Postfix version 3.1 and later:

       address_verify_pending_request_limit (see 'postconf -d' output)
              A safety limit that prevents address verification requests from overwhelming the Post‐
              fix queue.

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

       defer_transports (empty)
              The names of message delivery transports that should not deliver mail  unless  someone
              issues "sendmail -q" or equivalent.

       delay_logging_resolution_limit (2)
              The  maximal  number  of  digits after the decimal point when logging sub-second delay
              values.

       helpful_warnings (yes)
              Log warnings about problematic configuration settings,  and  provide  helpful  sugges‐
              tions.

       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.

       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 exam‐
              ple, "smtpd" becomes "prefix/smtpd".

       Available in Postfix version 3.0 and later:

       confirm_delay_cleared (no)
              After sending a "your message is delayed" notification, inform the sender when the de‐
              lay clears up.

       Available in Postfix 3.3 and later:

       service_name (read-only)
              The master.cf service name of a Postfix daemon process.

       Available in Postfix 3.5 and later:

       info_log_address_format (external)
              The email address form that will be used in non-debug logging (info, warning, etc.).

FILES
       /var/spool/postfix/incoming, incoming queue
       /var/spool/postfix/active, active queue
       /var/spool/postfix/deferred, deferred queue
       /var/spool/postfix/bounce, non-delivery status
       /var/spool/postfix/defer, non-delivery status
       /var/spool/postfix/trace, delivery status

SEE ALSO
       trivial-rewrite(8), address routing
       bounce(8), delivery status reports
       postconf(5), configuration parameters
       master(5), generic daemon options
       master(8), process manager
       postlogd(8), Postfix logging
       syslogd(8), system logging

README FILES
       Use "postconf readme_directory" or "postconf html_directory" to locate this information.
       QSHAPE_README, Postfix queue analysis

LICENSE
       The Secure Mailer license must be distributed with this software.

AUTHOR(S)
       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



                                                                                     OQMGR(8postfix)