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netbsd/external/ibm-public/postfix/dist/html/qmgr.8.html
Lionel Sambuc 10406efeac 2013/12/1 12:00:00 UTC
2014-01-15 10:53:42 +01:00

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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>triv-</b></a>
<a href="trivial-rewrite.8.html"><b>ial-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 discarded. 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> direc-
tory.
<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>" com-
mand. These files are maintained 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 message 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 deliver-
ies to the same destination.
<b>round robin</b>
The queue manager sorts delivery requests by desti-
nation. Round-robin selection prevents one desti-
nation from dominating deliveries to other destina-
tions.
<b>exponential backoff</b>
Mail that cannot be delivered upon the first
attempt is deferred. The time interval between
delivery attempts is doubled after each attempt.
<b>destination status cache</b>
The queue manager avoids unnecessary delivery
attempts by maintaining a short-term, in-memory
list of unreachable destinations.
<b>preemptive message scheduling</b>
The queue manager attempts to minimize the average
per-recipient delay while still preserving the cor-
rect per-message delays, using a sophisticated pre-
emptive 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 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):
<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 for-
ever. 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 trig-
gers. 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 outside world, and it
can be run at fixed low privilege in a chrooted environ-
ment.
<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 postmaster is notified of bounces and of other trou-
ble.
<b>BUGS</b>
A single queue manager process has to compete for disk
access with multiple 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 persistent 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 <b>mas-</b>
<b>ter.cf</b> 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 $default_fil-
ter_nexthop instead; when that value is empty, use
the domain in the recipient address.
<b>ACTIVE QUEUE CONTROLS</b>
<b><a href="postconf.5.html#qmgr_clog_warn_time">qmgr_clog_warn_time</a> (300s)</b>
The minimal delay between warnings that a specific
destination is clogging up the Postfix active
queue.
<b><a href="postconf.5.html#qmgr_message_active_limit">qmgr_message_active_limit</a> (20000)</b>
The maximal number of messages in the <a href="QSHAPE_README.html#active_queue">active queue</a>.
<b><a href="postconf.5.html#qmgr_message_recipient_limit">qmgr_message_recipient_limit</a> (20000)</b>
The maximal number of recipients held in memory by
the Postfix queue manager, and the maximal size of
the short-term, in-memory "dead" destination status
cache.
<b><a href="postconf.5.html#qmgr_message_recipient_minimum">qmgr_message_recipient_minimum</a> (10)</b>
The minimal number of in-memory recipients for any
message.
<b><a href="postconf.5.html#default_recipient_limit">default_recipient_limit</a> (20000)</b>
The default per-transport upper limit on the number
of in-memory recipients.
<b><a href="postconf.5.html#transport_recipient_limit"><i>transport</i>_recipient_limit</a> ($<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> ($<a href="postconf.5.html#default_extra_recipient_limit">default_extra_recipi</a>-</b>
<b><a href="postconf.5.html#default_extra_recipient_limit">ent_limit</a>)</b>
Idem, for delivery via the named message <i>transport</i>.
Available in Postfix version 2.4 and later:
<b><a href="postconf.5.html#default_recipient_refill_limit">default_recipient_refill_limit</a> (100)</b>
The default per-transport limit on the number of
recipients refilled at once.
<b><a href="postconf.5.html#transport_recipient_refill_limit"><i>transport</i>_recipient_refill_limit</a> ($<a href="postconf.5.html#default_recipient_refill_limit">default_recipi</a>-</b>
<b><a href="postconf.5.html#default_recipient_refill_limit">ent_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> ($<a href="postconf.5.html#default_recipient_refill_delay">default_recipi</a>-</b>
<b><a href="postconf.5.html#default_recipient_refill_delay">ent_refill_delay</a>)</b>
Idem, for delivery via the named message <i>transport</i>.
<b>DELIVERY CONCURRENCY CONTROLS</b>
<b><a href="postconf.5.html#initial_destination_concurrency">initial_destination_concurrency</a> (5)</b>
The initial per-destination concurrency level for
parallel delivery to the same destination.
<b><a href="postconf.5.html#default_destination_concurrency_limit">default_destination_concurrency_limit</a> (20)</b>
The default maximal number of parallel deliveries
to the same destination.
<b><a href="postconf.5.html#transport_destination_concurrency_limit"><i>transport</i>_destination_concurrency_limit</a> ($<a href="postconf.5.html#default_destination_concurrency_limit">default_destina</a>-</b>
<b><a href="postconf.5.html#default_destination_concurrency_limit">tion_concurrency_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> ($<a href="postconf.5.html#initial_destination_concurrency">initial_desti</a>-</b>
<b><a href="postconf.5.html#initial_destination_concurrency">nation_concurrency</a>)</b>
Initial concurrency for delivery via the named mes-
sage <i>transport</i>.
<b><a href="postconf.5.html#default_destination_concurrency_failed_cohort_limit">default_destination_concurrency_failed_cohort_limit</a> (1)</b>
How many pseudo-cohorts must suffer connection or
handshake failure before a specific destination is
considered unavailable (and further delivery is
suspended).
<b><a href="postconf.5.html#transport_destination_concurrency_failed_cohort_limit"><i>transport</i>_destination_concurrency_failed_cohort_limit</a></b>
<b>($<a href="postconf.5.html#default_destination_concurrency_failed_cohort_limit">default_destination_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 handshake failure.
<b><a href="postconf.5.html#transport_destination_concurrency_negative_feedback"><i>transport</i>_destination_concurrency_negative_feedback</a></b>
<b>($<a href="postconf.5.html#default_destination_concurrency_negative_feedback">default_destination_concurrency_negative_feedback</a>)</b>
Idem, for delivery via the named message <i>transport</i>.
<b><a href="postconf.5.html#default_destination_concurrency_positive_feedback">default_destination_concurrency_positive_feedback</a> (1)</b>
The per-destination amount of delivery concurrency
positive feedback, after a delivery completes with-
out connection or handshake failure.
<b><a href="postconf.5.html#transport_destination_concurrency_positive_feedback"><i>transport</i>_destination_concurrency_positive_feedback</a></b>
<b>($<a href="postconf.5.html#default_destination_concurrency_positive_feedback">default_destination_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 performance 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 mes-
sage delivery.
<b><a href="postconf.5.html#transport_destination_recipient_limit"><i>transport</i>_destination_recipient_limit</a> ($<a href="postconf.5.html#default_destination_recipient_limit">default_destina</a>-</b>
<b><a href="postconf.5.html#default_destination_recipient_limit">tion_recipient_limit</a>)</b>
Idem, for delivery via the named message <i>transport</i>.
<b>MESSAGE SCHEDULING CONTROLS</b>
<b><a href="postconf.5.html#default_delivery_slot_cost">default_delivery_slot_cost</a> (5)</b>
How often the Postfix queue manager's scheduler is
allowed to preempt delivery of one message with
another.
<b><a href="postconf.5.html#transport_delivery_slot_cost"><i>transport</i>_delivery_slot_cost</a> ($<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 algo-
rithm at all.
<b><a href="postconf.5.html#transport_minimum_delivery_slots"><i>transport</i>_minimum_delivery_slots</a> ($<a href="postconf.5.html#default_minimum_delivery_slots">default_minimum_deliv</a>-</b>
<b><a href="postconf.5.html#default_minimum_delivery_slots">ery_slots</a>)</b>
Idem, for delivery via the named message <i>transport</i>.
<b><a href="postconf.5.html#default_delivery_slot_discount">default_delivery_slot_discount</a> (50)</b>
The default value for transport-specific _deliv-
ery_slot_discount settings.
<b><a href="postconf.5.html#transport_delivery_slot_discount"><i>transport</i>_delivery_slot_discount</a> ($<a href="postconf.5.html#default_delivery_slot_discount">default_deliv</a>-</b>
<b><a href="postconf.5.html#default_delivery_slot_discount">ery_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 _deliv-
ery_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>
The maximal time a message is queued before it is
sent back as undeliverable.
<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 man-
ager to contact 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>
The maximal time a bounce message is queued before
it is considered undeliverable.
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 destina-
tion; the resulting behavior depends on the value
of the corresponding per-destination recipient
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_destina</a>-</b>
<b><a href="postconf.5.html#default_destination_rate_delay">tion_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 information 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> configuration 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 logging sub-second delay values.
<b><a href="postconf.5.html#helpful_warnings">helpful_warnings</a> (yes)</b>
Log warnings about problematic configuration set-
tings, and provide 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 direc-
tory.
<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, "postfix/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)
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