{
    "mode": "man",
    "parameter": "oqmgr",
    "section": "8postfix",
    "url": "https://www.chedong.com/phpMan.php/man/oqmgr/8postfix/json",
    "generated": "2026-10-05T20:22:34Z",
    "synopsis": "oqmgr [generic Postfix daemon options]",
    "sections": {
        "NAME": {
            "content": "oqmgr - old Postfix queue manager\n",
            "subsections": []
        },
        "SYNOPSIS": {
            "content": "oqmgr [generic Postfix daemon options]\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "The  oqmgr(8)  daemon  awaits  the arrival of incoming mail and arranges for its delivery via\nPostfix delivery processes.  The actual mail routing  strategy  is  delegated  to  the  triv‐\nial-rewrite(8) daemon.  This program expects to be run from the master(8) process manager.\n\nMail addressed to the local double-bounce address is logged and discarded.  This stops poten‐\ntial loops caused by undeliverable bounce notifications.\n",
            "subsections": []
        },
        "MAIL QUEUES": {
            "content": "The oqmgr(8) daemon maintains the following queues:\n",
            "subsections": [
                {
                    "name": "incoming",
                    "content": "Inbound mail from the network, or mail picked up by the local pickup(8) agent from the\nmaildrop directory.\n\nactive Messages that the queue manager has opened for delivery. Only a limited number of mes‐\nsages  is allowed to enter the active queue (leaky bucket strategy, for a fixed deliv‐\nery rate).\n"
                },
                {
                    "name": "deferred",
                    "content": "Mail that could not be delivered upon the first attempt. The queue manager  implements\nexponential backoff by doubling the time between delivery attempts.\n"
                },
                {
                    "name": "corrupt",
                    "content": "Unreadable or damaged queue files are moved here for inspection.\n\nhold   Messages that are kept \"on hold\" are kept here until someone sets them free.\n"
                }
            ]
        },
        "DELIVERY STATUS REPORTS": {
            "content": "The  oqmgr(8) daemon keeps an eye on per-message delivery status reports in the following di‐\nrectories. Each status report file has the same name as the corresponding message file:\n\nbounce Per-recipient status information about why mail is bounced.   These  files  are  main‐\ntained by the bounce(8) daemon.\n\ndefer  Per-recipient  status  information  about  why mail is delayed.  These files are main‐\ntained by the defer(8) daemon.\n\ntrace  Per-recipient status information as requested with the Postfix \"sendmail -v\" or \"send‐\nmail -bv\" command.  These files are maintained by the trace(8) daemon.\n\nThe oqmgr(8) daemon is responsible for asking the bounce(8), defer(8) or trace(8) daemons  to\nsend delivery reports.\n",
            "subsections": []
        },
        "STRATEGIES": {
            "content": "The  queue  manager implements a variety of strategies for either opening queue files (input)\nor for message delivery (output).\n",
            "subsections": [
                {
                    "name": "leaky bucket",
                    "content": "This strategy limits the number of messages in the active queue and prevents the queue\nmanager from running out of memory under heavy load.\n"
                },
                {
                    "name": "fairness",
                    "content": "When the active queue has room, the queue manager takes one message from the  incoming\nqueue  and one from the deferred queue. This prevents a large mail backlog from block‐\ning the delivery of new mail.\n"
                },
                {
                    "name": "slow start",
                    "content": "This strategy eliminates \"thundering herd\" problems by slowly adjusting the number  of\nparallel deliveries to the same destination.\n"
                },
                {
                    "name": "round robin",
                    "content": "The  queue manager sorts delivery requests by destination.  Round-robin selection pre‐\nvents one destination from dominating deliveries to other destinations.\n"
                },
                {
                    "name": "exponential backoff",
                    "content": "Mail that cannot be delivered upon the first attempt is deferred.  The  time  interval\nbetween delivery attempts is doubled after each attempt.\n"
                },
                {
                    "name": "destination status cache",
                    "content": "The  queue  manager  avoids unnecessary delivery attempts by maintaining a short-term,\nin-memory list of unreachable destinations.\n"
                }
            ]
        },
        "TRIGGERS": {
            "content": "On an idle system, the queue manager waits for the arrival of trigger events, or it waits for\na timer to go off. A trigger is a one-byte message.  Depending on the message  received,  the\nqueue  manager performs one of the following actions (the message is followed by the symbolic\nconstant used internally by the software):\n",
            "subsections": [
                {
                    "name": "D (QMGR_REQ_SCAN_DEFERRED)",
                    "content": "Start a deferred queue scan.  If a deferred queue scan is already  in  progress,  that\nscan will be restarted as soon as it finishes.\n"
                },
                {
                    "name": "I (QMGR_REQ_SCAN_INCOMING)",
                    "content": "Start  an  incoming queue scan. If an incoming queue scan is already in progress, that\nscan will be restarted as soon as it finishes.\n"
                },
                {
                    "name": "A (QMGR_REQ_SCAN_ALL)",
                    "content": "Ignore deferred queue file time stamps. The request affects the  next  deferred  queue\nscan.\n"
                },
                {
                    "name": "F (QMGR_REQ_FLUSH_DEAD)",
                    "content": "Purge all information about dead transports and destinations.\n"
                },
                {
                    "name": "W (TRIGGER_REQ_WAKEUP)",
                    "content": "Wakeup  call, This is used by the master server to instantiate servers that should not\ngo away forever. The action is to start an incoming queue scan.\n\nThe oqmgr(8) daemon reads an entire buffer worth of triggers.  Multiple identical trigger re‐\nquests are collapsed into one, and trigger requests are sorted so that A and F precede D  and\nI.  Thus, in order to force a deferred queue run, one would request A F D; in order to notify\nthe queue manager of the arrival of new mail one would request I.\n"
                }
            ]
        },
        "STANDARDS": {
            "content": "RFC 3463 (Enhanced status codes)\nRFC 3464 (Delivery status notifications)\n",
            "subsections": []
        },
        "SECURITY": {
            "content": "The oqmgr(8) daemon is not security sensitive. It reads single-character  messages  from  un‐\ntrusted  local  users, and thus may be susceptible to denial of service attacks. The oqmgr(8)\ndaemon does not talk to the outside world, and it can be run at fixed low privilege in a  ch‐\nrooted environment.\n",
            "subsections": []
        },
        "DIAGNOSTICS": {
            "content": "Problems and transactions are logged to the syslogd(8) or postlogd(8) daemon.  Corrupted mes‐\nsage files are saved to the corrupt queue for further inspection.\n\nDepending  on  the  setting  of  the  notifyclasses parameter, the postmaster is notified of\nbounces and of other trouble.\n",
            "subsections": []
        },
        "BUGS": {
            "content": "A single queue manager process has  to  compete  for  disk  access  with  multiple  front-end\nprocesses  such  as cleanup(8). A sudden burst of inbound mail can negatively impact outbound\ndelivery rates.\n",
            "subsections": []
        },
        "CONFIGURATION PARAMETERS": {
            "content": "Changes to main.cf are not picked up automatically, as oqmgr(8) is a persistent process.  Use\nthe command \"postfix reload\" after a configuration change.\n\nThe  text below provides only a parameter summary. See postconf(5) for more details including\nexamples.\n\nIn the text below, transport is the first field in a master.cf entry.\n",
            "subsections": []
        },
        "COMPATIBILITY CONTROLS": {
            "content": "Available before Postfix version 2.5:\n",
            "subsections": [
                {
                    "name": "allow_min_user (no)",
                    "content": "Allow a sender or recipient address to have `-' as the first character.\n\nAvailable with Postfix version 2.7 and later:\n"
                },
                {
                    "name": "default_filter_nexthop (empty)",
                    "content": "When a contentfilter or FILTER request specifies no  explicit  next-hop  destination,\nuse  $defaultfilternexthop  instead; when that value is empty, use the domain in the\nrecipient address.\n"
                }
            ]
        },
        "ACTIVE QUEUE CONTROLS": {
            "content": "",
            "subsections": [
                {
                    "name": "qmgr_clog_warn_time (300s)",
                    "content": "The minimal delay between warnings that a specific  destination  is  clogging  up  the\nPostfix active queue.\n"
                },
                {
                    "name": "qmgr_message_active_limit (20000)",
                    "content": "The maximal number of messages in the active queue.\n"
                },
                {
                    "name": "qmgr_message_recipient_limit (20000)",
                    "content": "The  maximal number of recipients held in memory by the Postfix queue manager, and the\nmaximal size of the short-term, in-memory \"dead\" destination status cache.\n"
                }
            ]
        },
        "DELIVERY CONCURRENCY CONTROLS": {
            "content": "",
            "subsections": [
                {
                    "name": "qmgr_fudge_factor (100)",
                    "content": "Obsolete feature: the percentage of delivery resources that a busy  mail  system  will\nuse up for delivery of a large mailing  list message.\n"
                },
                {
                    "name": "initial_destination_concurrency (5)",
                    "content": "The initial per-destination concurrency level for parallel delivery to the same desti‐\nnation.\n"
                },
                {
                    "name": "default_destination_concurrency_limit (20)",
                    "content": "The default maximal number of parallel deliveries to the same destination.\n"
                },
                {
                    "name": "transport_destination_concurrency_limit ($default_destination_concurrency_limit)",
                    "content": "A  transport-specific override for the defaultdestinationconcurrencylimit parameter\nvalue, where transport is the master.cf name of the message delivery transport.\n\nAvailable in Postfix version 2.5 and later:\n"
                },
                {
                    "name": "transport_initial_destination_concurrency ($initial_destination_concurrency)",
                    "content": "A transport-specific override for the initialdestinationconcurrency parameter value,\nwhere transport is the master.cf name of the message delivery transport.\n"
                },
                {
                    "name": "default_destination_concurrency_failed_cohort_limit (1)",
                    "content": "How many pseudo-cohorts must suffer connection or handshake failure before a  specific\ndestination is considered unavailable (and further delivery is suspended).\n"
                },
                {
                    "name": "transport_destination_concurrency_failed_cohort_limit ($default_destination_concur‐",
                    "content": ""
                },
                {
                    "name": "rency_failed_cohort_limit)",
                    "content": "A   transport-specific  override  for  the  defaultdestinationconcurrencyfailedco‐\nhortlimit parameter value, where transport is the master.cf name of the  message  de‐\nlivery transport.\n"
                },
                {
                    "name": "default_destination_concurrency_negative_feedback (1)",
                    "content": "The per-destination amount of delivery concurrency negative feedback, after a delivery\ncompletes with a connection or handshake failure.\n"
                },
                {
                    "name": "transport_destination_concurrency_negative_feedback ($default_destination_concurrency_nega‐",
                    "content": ""
                },
                {
                    "name": "tive_feedback)",
                    "content": "A  transport-specific  override for the defaultdestinationconcurrencynegativefeed‐\nback parameter value, where transport is the master.cf name of  the  message  delivery\ntransport.\n"
                },
                {
                    "name": "default_destination_concurrency_positive_feedback (1)",
                    "content": "The per-destination amount of delivery concurrency positive feedback, after a delivery\ncompletes without connection or handshake failure.\n"
                },
                {
                    "name": "transport_destination_concurrency_positive_feedback ($default_destination_concurrency_posi‐",
                    "content": ""
                },
                {
                    "name": "tive_feedback)",
                    "content": "A  transport-specific  override for the defaultdestinationconcurrencypositivefeed‐\nback parameter value, where transport is the master.cf name of  the  message  delivery\ntransport.\n"
                },
                {
                    "name": "destination_concurrency_feedback_debug (no)",
                    "content": "Make the queue manager's feedback algorithm verbose for performance analysis purposes.\n"
                }
            ]
        },
        "RECIPIENT SCHEDULING CONTROLS": {
            "content": "",
            "subsections": [
                {
                    "name": "default_destination_recipient_limit (50)",
                    "content": "The default maximal number of recipients per message delivery.\n"
                },
                {
                    "name": "transport_destination_recipient_limit ($default_destination_recipient_limit)",
                    "content": "A  transport-specific  override  for the defaultdestinationrecipientlimit parameter\nvalue, where transport is the master.cf name of the message delivery transport.\n"
                }
            ]
        },
        "OTHER RESOURCE AND RATE CONTROLS": {
            "content": "",
            "subsections": [
                {
                    "name": "minimal_backoff_time (300s)",
                    "content": "The minimal time between attempts to deliver a deferred message; prior to Postfix  2.4\nthe default value was 1000s.\n"
                },
                {
                    "name": "maximal_backoff_time (4000s)",
                    "content": "The maximal time between attempts to deliver a deferred message.\n"
                },
                {
                    "name": "maximal_queue_lifetime (5d)",
                    "content": "Consider  a  message as undeliverable, when delivery fails with a temporary error, and\nthe time in the queue has reached the maximalqueuelifetime limit.\n"
                },
                {
                    "name": "queue_run_delay (300s)",
                    "content": "The time between deferred queue scans by the queue manager; prior to Postfix  2.4  the\ndefault value was 1000s.\n"
                },
                {
                    "name": "transport_retry_time (60s)",
                    "content": "The  time  between  attempts  by the Postfix queue manager to contact a malfunctioning\nmessage delivery transport.\n\nAvailable in Postfix version 2.1 and later:\n"
                },
                {
                    "name": "bounce_queue_lifetime (5d)",
                    "content": "Consider a bounce message as undeliverable, when delivery fails with a  temporary  er‐\nror, and the time in the queue has reached the bouncequeuelifetime limit.\n\nAvailable in Postfix version 2.5 and later:\n"
                },
                {
                    "name": "default_destination_rate_delay (0s)",
                    "content": "The  default amount of delay that is inserted between individual message deliveries to\nthe same destination and over the same message delivery transport.\n"
                },
                {
                    "name": "transport_destination_rate_delay ($default_destination_rate_delay)",
                    "content": "A transport-specific override for the defaultdestinationratedelay parameter  value,\nwhere transport is the master.cf name of the message delivery transport.\n\nAvailable in Postfix version 3.1 and later:\n"
                },
                {
                    "name": "default_transport_rate_delay (0s)",
                    "content": "The  default  amount  of  delay that is inserted between individual message deliveries\nover the same message delivery transport, regardless of destination.\n"
                },
                {
                    "name": "transport_transport_rate_delay ($default_transport_rate_delay)",
                    "content": "A transport-specific override for the  defaulttransportratedelay  parameter  value,\nwhere the initial transport in the parameter name is the master.cf name of the message\ndelivery transport.\n"
                }
            ]
        },
        "SAFETY CONTROLS": {
            "content": "",
            "subsections": [
                {
                    "name": "qmgr_daemon_timeout (1000s)",
                    "content": "How  much  time a Postfix queue manager process may take to handle a request before it\nis terminated by a built-in watchdog timer.\n"
                },
                {
                    "name": "qmgr_ipc_timeout (60s)",
                    "content": "The time limit for the queue manager to send or receive information over  an  internal\ncommunication channel.\n\nAvailable in Postfix version 3.1 and later:\n"
                },
                {
                    "name": "address_verify_pending_request_limit (see 'postconf -d' output)",
                    "content": "A safety limit that prevents address verification requests from overwhelming the Post‐\nfix queue.\n"
                }
            ]
        },
        "MISCELLANEOUS CONTROLS": {
            "content": "",
            "subsections": [
                {
                    "name": "config_directory (see 'postconf -d' output)",
                    "content": "The default location of the Postfix main.cf and master.cf configuration files.\n"
                },
                {
                    "name": "defer_transports (empty)",
                    "content": "The  names  of message delivery transports that should not deliver mail unless someone\nissues \"sendmail -q\" or equivalent.\n"
                },
                {
                    "name": "delay_logging_resolution_limit (2)",
                    "content": "The maximal number of digits after the decimal point  when  logging  sub-second  delay\nvalues.\n"
                },
                {
                    "name": "helpful_warnings (yes)",
                    "content": "Log  warnings  about  problematic  configuration settings, and provide helpful sugges‐\ntions.\n"
                },
                {
                    "name": "process_id (read-only)",
                    "content": "The process ID of a Postfix command or daemon process.\n"
                },
                {
                    "name": "process_name (read-only)",
                    "content": "The process name of a Postfix command or daemon process.\n"
                },
                {
                    "name": "queue_directory (see 'postconf -d' output)",
                    "content": "The location of the Postfix top-level queue directory.\n"
                },
                {
                    "name": "syslog_facility (mail)",
                    "content": "The syslog facility of Postfix logging.\n"
                },
                {
                    "name": "syslog_name (see 'postconf -d' output)",
                    "content": "A prefix that is prepended to the process name in syslog records, so that,  for  exam‐\nple, \"smtpd\" becomes \"prefix/smtpd\".\n\nAvailable in Postfix version 3.0 and later:\n"
                },
                {
                    "name": "confirm_delay_cleared (no)",
                    "content": "After sending a \"your message is delayed\" notification, inform the sender when the de‐\nlay clears up.\n\nAvailable in Postfix 3.3 and later:\n"
                },
                {
                    "name": "service_name (read-only)",
                    "content": "The master.cf service name of a Postfix daemon process.\n\nAvailable in Postfix 3.5 and later:\n"
                },
                {
                    "name": "info_log_address_format (external)",
                    "content": "The email address form that will be used in non-debug logging (info, warning, etc.).\n"
                }
            ]
        },
        "FILES": {
            "content": "/var/spool/postfix/incoming, incoming queue\n/var/spool/postfix/active, active queue\n/var/spool/postfix/deferred, deferred queue\n/var/spool/postfix/bounce, non-delivery status\n/var/spool/postfix/defer, non-delivery status\n/var/spool/postfix/trace, delivery status\n",
            "subsections": []
        },
        "SEE ALSO": {
            "content": "trivial-rewrite(8), address routing\nbounce(8), delivery status reports\npostconf(5), configuration parameters\nmaster(5), generic daemon options\nmaster(8), process manager\npostlogd(8), Postfix logging\nsyslogd(8), system logging\n",
            "subsections": []
        },
        "README FILES": {
            "content": "Use \"postconf readmedirectory\" or \"postconf htmldirectory\" to locate this information.\nQSHAPEREADME, Postfix queue analysis\n",
            "subsections": []
        },
        "LICENSE": {
            "content": "The Secure Mailer license must be distributed with this software.\n\nAUTHOR(S)\nWietse Venema\nIBM T.J. Watson Research\nP.O. Box 704\nYorktown Heights, NY 10598, USA\n\nWietse Venema\nGoogle, Inc.\n111 8th Avenue\nNew York, NY 10011, USA\n\nOQMGR(8postfix)",
            "subsections": []
        }
    },
    "summary": "oqmgr - old Postfix queue manager",
    "flags": [],
    "examples": [],
    "see_also": [
        {
            "name": "trivial-rewrite",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/trivial-rewrite/8/json"
        },
        {
            "name": "bounce",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/bounce/8/json"
        },
        {
            "name": "postconf",
            "section": "5",
            "url": "https://www.chedong.com/phpMan.php/man/postconf/5/json"
        },
        {
            "name": "master",
            "section": "5",
            "url": "https://www.chedong.com/phpMan.php/man/master/5/json"
        },
        {
            "name": "master",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/master/8/json"
        },
        {
            "name": "postlogd",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/postlogd/8/json"
        },
        {
            "name": "syslogd",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/syslogd/8/json"
        }
    ]
}