<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> <title> Postfix manual - qmgr(8) </title> </head> <body> <pre> QMGR(8) QMGR(8) <b>NAME</b> qmgr - Postfix queue manager <b>SYNOPSIS</b> <b>qmgr</b> [generic Postfix daemon options] <b>DESCRIPTION</b> The <a href="qmgr.8.html"><b>qmgr</b>(8)</a> 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 <a href="trivial-rewrite.8.html"><b>trivial-rewrite</b>(8)</a> daemon. This program expects to be run from the <a href="master.8.html"><b>master</b>(8)</a> process manager. Mail addressed to the local <b>double-bounce</b> address is logged and dis- carded. This stops potential loops caused by undeliverable bounce notifications. <b>MAIL QUEUES</b> The <a href="qmgr.8.html"><b>qmgr</b>(8)</a> daemon maintains the following queues: <b>incoming</b> Inbound mail from the network, or mail picked up by the local <a href="pickup.8.html"><b>pickup</b>(8)</a> daemon from the <b>maildrop</b> directory. <b>active</b> Messages that the queue manager has opened for delivery. Only a limited number of messages is allowed to enter the <b>active</b> queue (leaky bucket strategy, for a fixed delivery rate). <b>deferred</b> Mail that could not be delivered upon the first attempt. The queue manager implements exponential backoff by doubling the time between delivery attempts. <b>corrupt</b> Unreadable or damaged queue files are moved here for inspection. <b>hold</b> Messages that are kept "on hold" are kept here until someone sets them free. <b>DELIVERY STATUS REPORTS</b> The <a href="qmgr.8.html"><b>qmgr</b>(8)</a> daemon keeps an eye on per-message delivery status reports in the following directories. Each status report file has the same name as the corresponding message file: <b>bounce</b> Per-recipient status information about why mail is bounced. These files are maintained by the <a href="bounce.8.html"><b>bounce</b>(8)</a> daemon. <b>defer</b> Per-recipient status information about why mail is delayed. These files are maintained by the <a href="defer.8.html"><b>defer</b>(8)</a> daemon. <b>trace</b> Per-recipient status information as requested with the Postfix "<b>sendmail -v</b>" or "<b>sendmail -bv</b>" command. These files are main- tained by the <a href="trace.8.html"><b>trace</b>(8)</a> daemon. The <a href="qmgr.8.html"><b>qmgr</b>(8)</a> daemon is responsible for asking the <a href="bounce.8.html"><b>bounce</b>(8)</a>, <a href="defer.8.html"><b>defer</b>(8)</a> or <a href="trace.8.html"><b>trace</b>(8)</a> daemons to send delivery reports. <b>STRATEGIES</b> The queue manager implements a variety of strategies for either opening queue files (input) or for message delivery (output). <b>leaky bucket</b> This strategy limits the number of messages in the <b>active</b> queue and prevents the queue manager from running out of memory under heavy load. <b>fairness</b> When the <b>active</b> queue has room, the queue manager takes one mes- sage from the <a href="QSHAPE_README.html#incoming_queue"><b>incoming</b> queue</a> and one from the <b>deferred</b> queue. This prevents a large mail backlog from blocking the delivery of new mail. <b>slow start</b> This strategy eliminates "thundering herd" problems by slowly adjusting the number of parallel deliveries to the same destina- tion. <b>round robin</b> The queue manager sorts delivery requests by destination. Round-robin selection prevents one destination from dominating deliveries to other destinations. <b>exponential backoff</b> Mail that cannot be delivered upon the first attempt is deferred. The time interval between delivery attempts is dou- bled after each attempt. <b>destination status cache</b> The queue manager avoids unnecessary delivery attempts by main- taining a short-term, in-memory list of unreachable destina- tions. <b>preemptive message scheduling</b> The queue manager attempts to minimize the average per-recipient delay while still preserving the correct per-message delays, using a sophisticated preemptive message scheduling. <b>TRIGGERS</b> 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 mes- sage. 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): <b>D (QMGR_REQ_SCAN_DEFERRED)</b> Start a <a href="QSHAPE_README.html#deferred_queue">deferred queue</a> scan. If a deferred queue scan is already in progress, that scan will be restarted as soon as it finishes. <b>I (QMGR_REQ_SCAN_INCOMING)</b> Start an <a href="QSHAPE_README.html#incoming_queue">incoming queue</a> scan. If an incoming queue scan is already in progress, that scan will be restarted as soon as it finishes. <b>A (QMGR_REQ_SCAN_ALL)</b> Ignore <a href="QSHAPE_README.html#deferred_queue">deferred queue</a> file time stamps. The request affects the next <a href="QSHAPE_README.html#deferred_queue">deferred queue</a> scan. <b>F (QMGR_REQ_FLUSH_DEAD)</b> Purge all information about dead transports and destinations. <b>W (TRIGGER_REQ_WAKEUP)</b> Wakeup call, This is used by the master server to instantiate servers that should not go away forever. The action is to start an <a href="QSHAPE_README.html#incoming_queue">incoming queue</a> scan. The <a href="qmgr.8.html"><b>qmgr</b>(8)</a> daemon reads an entire buffer worth of triggers. Multiple identical trigger requests are collapsed into one, and trigger requests are sorted so that <b>A</b> and <b>F</b> precede <b>D</b> and <b>I</b>. Thus, in order to force a <a href="QSHAPE_README.html#deferred_queue">deferred queue</a> run, one would request <b>A F D</b>; in order to notify the queue manager of the arrival of new mail one would request <b>I</b>. <b>STANDARDS</b> <a href="http://tools.ietf.org/html/rfc3463">RFC 3463</a> (Enhanced status codes) <a href="http://tools.ietf.org/html/rfc3464">RFC 3464</a> (Delivery status notifications) <b>SECURITY</b> The <a href="qmgr.8.html"><b>qmgr</b>(8)</a> daemon is not security sensitive. It reads single-character messages from untrusted local users, and thus may be susceptible to denial of service attacks. The <a href="qmgr.8.html"><b>qmgr</b>(8)</a> daemon does not talk to the out- side world, and it can be run at fixed low privilege in a chrooted environment. <b>DIAGNOSTICS</b> Problems and transactions are logged to the syslog daemon. Corrupted message files are saved to the <b>corrupt</b> queue for further inspection. Depending on the setting of the <b><a href="postconf.5.html#notify_classes">notify_classes</a></b> parameter, the postmas- ter is notified of bounces and of other trouble. <b>BUGS</b> A single queue manager process has to compete for disk access with mul- tiple front-end processes such as <a href="cleanup.8.html"><b>cleanup</b>(8)</a>. A sudden burst of inbound mail can negatively impact outbound delivery rates. <b>CONFIGURATION PARAMETERS</b> Changes to <a href="postconf.5.html"><b>main.cf</b></a> are not picked up automatically as <a href="qmgr.8.html"><b>qmgr</b>(8)</a> is a per- sistent process. Use the "<b>postfix reload</b>" command after a configuration change. The text below provides only a parameter summary. See <a href="postconf.5.html"><b>postconf</b>(5)</a> for more details including examples. In the text below, <i>transport</i> is the first field in a <a href="master.5.html"><b>master.cf</b></a> entry. <b>COMPATIBILITY CONTROLS</b> Available before Postfix version 2.5: <b><a href="postconf.5.html#allow_min_user">allow_min_user</a> (no)</b> Allow a sender or recipient address to have `-' as the first character. Available with Postfix version 2.7 and later: <b><a href="postconf.5.html#default_filter_nexthop">default_filter_nexthop</a> (empty)</b> When a <a href="postconf.5.html#content_filter">content_filter</a> or FILTER request specifies no explicit next-hop destination, use $<a href="postconf.5.html#default_filter_nexthop">default_filter_nexthop</a> instead; when that value is empty, use the domain in the recipient address. <b>ACTIVE QUEUE CONTROLS</b> <b><a href="postconf.5.html#qmgr_clog_warn_time">qmgr_clog_warn_time</a> (300s)</b> The minimal delay between warnings that a specific destination is clogging up the Postfix <a href="QSHAPE_README.html#active_queue">active queue</a>. <b><a href="postconf.5.html#qmgr_message_active_limit">qmgr_message_active_limit</a> (20000)</b> The maximal number of messages in the <a href="QSHAPE_README.html#active_queue">active queue</a>. <b><a href="postconf.5.html#qmgr_message_recipient_limit">qmgr_message_recipient_limit</a> (20000)</b> The maximal number of recipients held in memory by the Postfix queue manager, and the maximal size of the short-term, in-memory "dead" destination status cache. <b><a href="postconf.5.html#qmgr_message_recipient_minimum">qmgr_message_recipient_minimum</a> (10)</b> The minimal number of in-memory recipients for any message. <b><a href="postconf.5.html#default_recipient_limit">default_recipient_limit</a> (20000)</b> The default per-transport upper limit on the number of in-memory recipients. <b><a href="postconf.5.html#transport_recipient_limit"><i>transport</i>_recipient_limit</a> ($<a href="postconf.5.html#default_recipient_limit">default_recipient_limit</a>)</b> Idem, for delivery via the named message <i>transport</i>. <b><a href="postconf.5.html#default_extra_recipient_limit">default_extra_recipient_limit</a> (1000)</b> The default value for the extra per-transport limit imposed on the number of in-memory recipients. <b><a href="postconf.5.html#transport_extra_recipient_limit"><i>transport</i>_extra_recipient_limit</a> ($<a href="postconf.5.html#default_extra_recipient_limit">default_extra_recipient_limit</a>)</b> Idem, for delivery via the named message <i>transport</i>. Available in Postfix version 2.4 and later: <b><a href="postconf.5.html#default_recipient_refill_limit">default_recipient_refill_limit</a> (100)</b> The default per-transport limit on the number of recipients refilled at once. <b><a href="postconf.5.html#transport_recipient_refill_limit"><i>transport</i>_recipient_refill_limit</a> ($<a href="postconf.5.html#default_recipient_refill_limit">default_recipient_refill_limit</a>)</b> Idem, for delivery via the named message <i>transport</i>. <b><a href="postconf.5.html#default_recipient_refill_delay">default_recipient_refill_delay</a> (5s)</b> The default per-transport maximum delay between recipients refills. <b><a href="postconf.5.html#transport_recipient_refill_delay"><i>transport</i>_recipient_refill_delay</a> ($<a href="postconf.5.html#default_recipient_refill_delay">default_recipient_refill_delay</a>)</b> Idem, for delivery via the named message <i>transport</i>. <b>DELIVERY CONCURRENCY CONTROLS</b> <b><a href="postconf.5.html#initial_destination_concurrency">initial_destination_concurrency</a> (5)</b> The initial per-destination concurrency level for parallel delivery to the same destination. <b><a href="postconf.5.html#default_destination_concurrency_limit">default_destination_concurrency_limit</a> (20)</b> The default maximal number of parallel deliveries to the same destination. <b><a href="postconf.5.html#transport_destination_concurrency_limit"><i>transport</i>_destination_concurrency_limit</a> ($<a href="postconf.5.html#default_destination_concurrency_limit">default_destination_concur</a>-</b> <b><a href="postconf.5.html#default_destination_concurrency_limit">rency_limit</a>)</b> Idem, for delivery via the named message <i>transport</i>. Available in Postfix version 2.5 and later: <b><a href="postconf.5.html#transport_initial_destination_concurrency"><i>transport</i>_initial_destination_concurrency</a> ($<a href="postconf.5.html#initial_destination_concurrency">initial_destination_concur</a>-</b> <b><a href="postconf.5.html#initial_destination_concurrency">rency</a>)</b> Initial concurrency for delivery via the named message <i>trans-</i> <i>port</i>. <b><a href="postconf.5.html#default_destination_concurrency_failed_cohort_limit">default_destination_concurrency_failed_cohort_limit</a> (1)</b> How many pseudo-cohorts must suffer connection or handshake failure before a specific destination is considered unavailable (and further delivery is suspended). <b><a href="postconf.5.html#transport_destination_concurrency_failed_cohort_limit"><i>transport</i>_destination_concurrency_failed_cohort_limit</a> ($<a href="postconf.5.html#default_destination_concurrency_failed_cohort_limit">default_desti</a>-</b> <b><a href="postconf.5.html#default_destination_concurrency_failed_cohort_limit">nation_concurrency_failed_cohort_limit</a>)</b> Idem, for delivery via the named message <i>transport</i>. <b><a href="postconf.5.html#default_destination_concurrency_negative_feedback">default_destination_concurrency_negative_feedback</a> (1)</b> The per-destination amount of delivery concurrency negative feedback, after a delivery completes with a connection or hand- shake failure. <b><a href="postconf.5.html#transport_destination_concurrency_negative_feedback"><i>transport</i>_destination_concurrency_negative_feedback</a> ($<a href="postconf.5.html#default_destination_concurrency_negative_feedback">default_destina</a>-</b> <b><a href="postconf.5.html#default_destination_concurrency_negative_feedback">tion_concurrency_negative_feedback</a>)</b> Idem, for delivery via the named message <i>transport</i>. <b><a href="postconf.5.html#default_destination_concurrency_positive_feedback">default_destination_concurrency_positive_feedback</a> (1)</b> The per-destination amount of delivery concurrency positive feedback, after a delivery completes without connection or hand- shake failure. <b><a href="postconf.5.html#transport_destination_concurrency_positive_feedback"><i>transport</i>_destination_concurrency_positive_feedback</a> ($<a href="postconf.5.html#default_destination_concurrency_positive_feedback">default_destina</a>-</b> <b><a href="postconf.5.html#default_destination_concurrency_positive_feedback">tion_concurrency_positive_feedback</a>)</b> Idem, for delivery via the named message <i>transport</i>. <b><a href="postconf.5.html#destination_concurrency_feedback_debug">destination_concurrency_feedback_debug</a> (no)</b> Make the queue manager's feedback algorithm verbose for perfor- mance analysis purposes. <b>RECIPIENT SCHEDULING CONTROLS</b> <b><a href="postconf.5.html#default_destination_recipient_limit">default_destination_recipient_limit</a> (50)</b> The default maximal number of recipients per message delivery. <b><a href="postconf.5.html#transport_destination_recipient_limit"><i>transport</i>_destination_recipient_limit</a> ($<a href="postconf.5.html#default_destination_recipient_limit">default_destination_recipi</a>-</b> <b><a href="postconf.5.html#default_destination_recipient_limit">ent_limit</a>)</b> Idem, for delivery via the named message <i>transport</i>. <b>MESSAGE SCHEDULING CONTROLS</b> <b><a href="postconf.5.html#default_delivery_slot_cost">default_delivery_slot_cost</a> (5)</b> How often the Postfix queue manager's scheduler is allowed to preempt delivery of one message with another. <b><a href="postconf.5.html#transport_delivery_slot_cost"><i>transport</i>_delivery_slot_cost</a> ($<a href="postconf.5.html#default_delivery_slot_cost">default_delivery_slot_cost</a>)</b> Idem, for delivery via the named message <i>transport</i>. <b><a href="postconf.5.html#default_minimum_delivery_slots">default_minimum_delivery_slots</a> (3)</b> How many recipients a message must have in order to invoke the Postfix queue manager's scheduling algorithm at all. <b><a href="postconf.5.html#transport_minimum_delivery_slots"><i>transport</i>_minimum_delivery_slots</a> ($<a href="postconf.5.html#default_minimum_delivery_slots">default_minimum_delivery_slots</a>)</b> Idem, for delivery via the named message <i>transport</i>. <b><a href="postconf.5.html#default_delivery_slot_discount">default_delivery_slot_discount</a> (50)</b> The default value for transport-specific _delivery_slot_discount settings. <b><a href="postconf.5.html#transport_delivery_slot_discount"><i>transport</i>_delivery_slot_discount</a> ($<a href="postconf.5.html#default_delivery_slot_discount">default_delivery_slot_discount</a>)</b> Idem, for delivery via the named message <i>transport</i>. <b><a href="postconf.5.html#default_delivery_slot_loan">default_delivery_slot_loan</a> (3)</b> The default value for transport-specific _delivery_slot_loan settings. <b><a href="postconf.5.html#transport_delivery_slot_loan"><i>transport</i>_delivery_slot_loan</a> ($<a href="postconf.5.html#default_delivery_slot_loan">default_delivery_slot_loan</a>)</b> Idem, for delivery via the named message <i>transport</i>. <b>OTHER RESOURCE AND RATE CONTROLS</b> <b><a href="postconf.5.html#minimal_backoff_time">minimal_backoff_time</a> (300s)</b> The minimal time between attempts to deliver a deferred message; prior to Postfix 2.4 the default value was 1000s. <b><a href="postconf.5.html#maximal_backoff_time">maximal_backoff_time</a> (4000s)</b> The maximal time between attempts to deliver a deferred message. <b><a href="postconf.5.html#maximal_queue_lifetime">maximal_queue_lifetime</a> (5d)</b> Consider a message as undeliverable, when delivery fails with a temporary error, and the time in the queue has reached the <a href="postconf.5.html#maximal_queue_lifetime">maxi</a>- <a href="postconf.5.html#maximal_queue_lifetime">mal_queue_lifetime</a> limit. <b><a href="postconf.5.html#queue_run_delay">queue_run_delay</a> (300s)</b> The time between <a href="QSHAPE_README.html#deferred_queue">deferred queue</a> scans by the queue manager; prior to Postfix 2.4 the default value was 1000s. <b><a href="postconf.5.html#transport_retry_time">transport_retry_time</a> (60s)</b> The time between attempts by the Postfix queue manager to con- tact a malfunctioning message delivery transport. Available in Postfix version 2.1 and later: <b><a href="postconf.5.html#bounce_queue_lifetime">bounce_queue_lifetime</a> (5d)</b> Consider a bounce message as undeliverable, when delivery fails with a temporary error, and the time in the queue has reached the <a href="postconf.5.html#bounce_queue_lifetime">bounce_queue_lifetime</a> limit. Available in Postfix version 2.5 and later: <b><a href="postconf.5.html#default_destination_rate_delay">default_destination_rate_delay</a> (0s)</b> The default amount of delay that is inserted between individual deliveries to the same destination; the resulting behavior depends on the value of the corresponding per-destination recip- ient limit. <b><a href="postconf.5.html#transport_destination_rate_delay"><i>transport</i>_destination_rate_delay</a> $<a href="postconf.5.html#default_destination_rate_delay">default_destination_rate_delay</a></b> Idem, for delivery via the named message <i>transport</i>. <b>SAFETY CONTROLS</b> <b><a href="postconf.5.html#qmgr_daemon_timeout">qmgr_daemon_timeout</a> (1000s)</b> How much time a Postfix queue manager process may take to handle a request before it is terminated by a built-in watchdog timer. <b><a href="postconf.5.html#qmgr_ipc_timeout">qmgr_ipc_timeout</a> (60s)</b> The time limit for the queue manager to send or receive informa- tion over an internal communication channel. <b>MISCELLANEOUS CONTROLS</b> <b><a href="postconf.5.html#config_directory">config_directory</a> (see 'postconf -d' output)</b> The default location of the Postfix <a href="postconf.5.html">main.cf</a> and <a href="master.5.html">master.cf</a> con- figuration files. <b><a href="postconf.5.html#defer_transports">defer_transports</a> (empty)</b> The names of message delivery transports that should not deliver mail unless someone issues "<b>sendmail -q</b>" or equivalent. <b><a href="postconf.5.html#delay_logging_resolution_limit">delay_logging_resolution_limit</a> (2)</b> The maximal number of digits after the decimal point when log- ging sub-second delay values. <b><a href="postconf.5.html#helpful_warnings">helpful_warnings</a> (yes)</b> Log warnings about problematic configuration settings, and pro- vide helpful suggestions. <b><a href="postconf.5.html#process_id">process_id</a> (read-only)</b> The process ID of a Postfix command or daemon process. <b><a href="postconf.5.html#process_name">process_name</a> (read-only)</b> The process name of a Postfix command or daemon process. <b><a href="postconf.5.html#queue_directory">queue_directory</a> (see 'postconf -d' output)</b> The location of the Postfix top-level queue directory. <b><a href="postconf.5.html#syslog_facility">syslog_facility</a> (mail)</b> The syslog facility of Postfix logging. <b><a href="postconf.5.html#syslog_name">syslog_name</a> (see 'postconf -d' output)</b> The mail system name that is prepended to the process name in syslog records, so that "smtpd" becomes, for example, "post- fix/smtpd". <b>FILES</b> /var/spool/postfix/incoming, <a href="QSHAPE_README.html#incoming_queue">incoming queue</a> /var/spool/postfix/active, <a href="QSHAPE_README.html#active_queue">active queue</a> /var/spool/postfix/deferred, <a href="QSHAPE_README.html#deferred_queue">deferred queue</a> /var/spool/postfix/bounce, non-delivery status /var/spool/postfix/defer, non-delivery status /var/spool/postfix/trace, delivery status <b>SEE ALSO</b> <a href="trivial-rewrite.8.html">trivial-rewrite(8)</a>, address routing <a href="bounce.8.html">bounce(8)</a>, delivery status reports <a href="postconf.5.html">postconf(5)</a>, configuration parameters <a href="master.5.html">master(5)</a>, generic daemon options <a href="master.8.html">master(8)</a>, process manager syslogd(8), system logging <b>README FILES</b> <a href="SCHEDULER_README.html">SCHEDULER_README</a>, scheduling algorithm <a href="QSHAPE_README.html">QSHAPE_README</a>, Postfix queue analysis <b>LICENSE</b> The Secure Mailer license must be distributed with this software. <b>AUTHOR(S)</b> Wietse Venema IBM T.J. Watson Research P.O. Box 704 Yorktown Heights, NY 10598, USA Preemptive scheduler enhancements: Patrik Rak Modra 6 155 00, Prague, Czech Republic QMGR(8) </pre> </body> </html>