1OQMGR(8)                    System Manager's Manual                   OQMGR(8)
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NAME

6       oqmgr - old Postfix queue manager
7

SYNOPSIS

9       oqmgr [generic Postfix daemon options]
10

DESCRIPTION

12       The  oqmgr(8)  daemon  awaits the arrival of incoming mail and arranges
13       for its delivery via Postfix delivery processes.  The actual mail rout‐
14       ing  strategy is delegated to the trivial-rewrite(8) daemon.  This pro‐
15       gram expects to be run from the master(8) process manager.
16
17       Mail addressed to the local double-bounce address is  logged  and  dis‐
18       carded.   This  stops  potential  loops  caused by undeliverable bounce
19       notifications.
20

MAIL QUEUES

22       The oqmgr(8) daemon maintains the following queues:
23
24       incoming
25              Inbound mail from the network, or mail picked up  by  the  local
26              pickup(8) agent from the maildrop directory.
27
28       active Messages  that the queue manager has opened for delivery. Only a
29              limited number of messages is allowed to enter the active  queue
30              (leaky bucket strategy, for a fixed delivery rate).
31
32       deferred
33              Mail  that  could  not  be delivered upon the first attempt. The
34              queue manager implements exponential  backoff  by  doubling  the
35              time between delivery attempts.
36
37       corrupt
38              Unreadable or damaged queue files are moved here for inspection.
39
40       hold   Messages  that  are  kept  "on hold" are kept here until someone
41              sets them free.
42

DELIVERY STATUS REPORTS

44       The oqmgr(8) daemon keeps an eye on per-message delivery status reports
45       in the following directories. Each status report file has the same name
46       as the corresponding message file:
47
48       bounce Per-recipient status information  about  why  mail  is  bounced.
49              These files are maintained by the bounce(8) daemon.
50
51       defer  Per-recipient  status  information  about  why  mail is delayed.
52              These files are maintained by the defer(8) daemon.
53
54       trace  Per-recipient status information as requested with  the  Postfix
55              "sendmail  -v" or "sendmail -bv" command.  These files are main‐
56              tained by the trace(8) daemon.
57
58       The oqmgr(8) daemon is responsible for asking the  bounce(8),  defer(8)
59       or trace(8) daemons to send delivery reports.
60

STRATEGIES

62       The queue manager implements a variety of strategies for either opening
63       queue files (input) or for message delivery (output).
64
65       leaky bucket
66              This strategy limits the number of messages in the active  queue
67              and  prevents the queue manager from running out of memory under
68              heavy load.
69
70       fairness
71              When the active queue has room, the queue manager takes one mes‐
72              sage  from  the  incoming queue and one from the deferred queue.
73              This prevents a large mail backlog from blocking the delivery of
74              new mail.
75
76       slow start
77              This  strategy  eliminates  "thundering herd" problems by slowly
78              adjusting the number of parallel deliveries to the same destina‐
79              tion.
80
81       round robin
82              The  queue  manager  sorts  delivery  requests  by  destination.
83              Round-robin selection prevents one destination  from  dominating
84              deliveries to other destinations.
85
86       exponential backoff
87              Mail  that  cannot  be  delivered  upon  the  first  attempt  is
88              deferred.  The time interval between delivery attempts  is  dou‐
89              bled after each attempt.
90
91       destination status cache
92              The  queue manager avoids unnecessary delivery attempts by main‐
93              taining a short-term, in-memory  list  of  unreachable  destina‐
94              tions.
95

TRIGGERS

97       On  an  idle system, the queue manager waits for the arrival of trigger
98       events, or it waits for a timer to go off. A trigger is a one-byte mes‐
99       sage.   Depending  on  the message received, the queue manager performs
100       one of the following actions (the message is followed by  the  symbolic
101       constant used internally by the software):
102
103       D (QMGR_REQ_SCAN_DEFERRED)
104              Start  a  deferred  queue  scan.   If  a  deferred queue scan is
105              already in progress, that scan will be restarted as soon  as  it
106              finishes.
107
108       I (QMGR_REQ_SCAN_INCOMING)
109              Start  an  incoming  queue  scan.  If  an incoming queue scan is
110              already in progress, that scan will be restarted as soon  as  it
111              finishes.
112
113       A (QMGR_REQ_SCAN_ALL)
114              Ignore  deferred queue file time stamps. The request affects the
115              next deferred queue scan.
116
117       F (QMGR_REQ_FLUSH_DEAD)
118              Purge all information about dead transports and destinations.
119
120       W (TRIGGER_REQ_WAKEUP)
121              Wakeup call, This is used by the master  server  to  instantiate
122              servers  that should not go away forever. The action is to start
123              an incoming queue scan.
124
125       The oqmgr(8) daemon reads an entire buffer worth of triggers.  Multiple
126       identical trigger requests are collapsed into one, and trigger requests
127       are sorted so that A and F precede D and I. Thus, in order to  force  a
128       deferred  queue  run,  one  would request A F D; in order to notify the
129       queue manager of the arrival of new mail one would request I.
130

STANDARDS

132       RFC 3463 (Enhanced status codes)
133       RFC 3464 (Delivery status notifications)
134

SECURITY

136       The oqmgr(8) daemon is not security sensitive. It reads  single-charac‐
137       ter messages from untrusted local users, and thus may be susceptible to
138       denial of service attacks. The oqmgr(8) daemon does  not  talk  to  the
139       outside  world,  and it can be run at fixed low privilege in a chrooted
140       environment.
141

DIAGNOSTICS

143       Problems and transactions are logged to the syslogd(8)  or  postlogd(8)
144       daemon.   Corrupted  message  files  are saved to the corrupt queue for
145       further inspection.
146
147       Depending on the setting of the notify_classes parameter, the  postmas‐
148       ter is notified of bounces and of other trouble.
149

BUGS

151       A single queue manager process has to compete for disk access with mul‐
152       tiple front-end processes such as cleanup(8). A sudden burst of inbound
153       mail can negatively impact outbound delivery rates.
154

CONFIGURATION PARAMETERS

156       Changes  to  main.cf  are not picked up automatically, as oqmgr(8) is a
157       persistent process. Use the command "postfix reload" after a configura‐
158       tion change.
159
160       The  text  below provides only a parameter summary. See postconf(5) for
161       more details including examples.
162
163       In the text below, transport is the first field in a master.cf entry.
164

COMPATIBILITY CONTROLS

166       Available before Postfix version 2.5:
167
168       allow_min_user (no)
169              Allow a sender or recipient address to have  `-'  as  the  first
170              character.
171
172       Available with Postfix version 2.7 and later:
173
174       default_filter_nexthop (empty)
175              When  a  content_filter  or FILTER request specifies no explicit
176              next-hop destination, use $default_filter_nexthop instead;  when
177              that value is empty, use the domain in the recipient address.
178

ACTIVE QUEUE CONTROLS

180       qmgr_clog_warn_time (300s)
181              The  minimal  delay between warnings that a specific destination
182              is clogging up the Postfix active queue.
183
184       qmgr_message_active_limit (20000)
185              The maximal number of messages in the active queue.
186
187       qmgr_message_recipient_limit (20000)
188              The maximal number of recipients held in memory by  the  Postfix
189              queue manager, and the maximal size of the short-term, in-memory
190              "dead" destination status cache.
191

DELIVERY CONCURRENCY CONTROLS

193       qmgr_fudge_factor (100)
194              Obsolete feature: the percentage of delivery  resources  that  a
195              busy  mail  system  will  use up for delivery of a large mailing
196              list message.
197
198       initial_destination_concurrency (5)
199              The  initial  per-destination  concurrency  level  for  parallel
200              delivery to the same destination.
201
202       default_destination_concurrency_limit (20)
203              The  default  maximal  number of parallel deliveries to the same
204              destination.
205
206       transport_destination_concurrency_limit   ($default_destination_concur‐
207       rency_limit)
208              A  transport-specific  override for the default_destination_con‐
209              currency_limit parameter value, where transport is the master.cf
210              name of the message delivery transport.
211
212       Available in Postfix version 2.5 and later:
213
214       transport_initial_destination_concurrency ($initial_destination_concur‐
215       rency)
216              A transport-specific override for  the  initial_destination_con‐
217              currency  parameter value, where transport is the master.cf name
218              of the message delivery transport.
219
220       default_destination_concurrency_failed_cohort_limit (1)
221              How many pseudo-cohorts  must  suffer  connection  or  handshake
222              failure  before a specific destination is considered unavailable
223              (and further delivery is suspended).
224
225       transport_destination_concurrency_failed_cohort_limit  ($default_desti‐
226       nation_concurrency_failed_cohort_limit)
227              A  transport-specific  override for the default_destination_con‐
228              currency_failed_cohort_limit parameter value, where transport is
229              the master.cf name of the message delivery transport.
230
231       default_destination_concurrency_negative_feedback (1)
232              The  per-destination  amount  of  delivery  concurrency negative
233              feedback, after a delivery completes with a connection or  hand‐
234              shake failure.
235
236       transport_destination_concurrency_negative_feedback  ($default_destina‐
237       tion_concurrency_negative_feedback)
238              A transport-specific override for  the  default_destination_con‐
239              currency_negative_feedback  parameter  value, where transport is
240              the master.cf name of the message delivery transport.
241
242       default_destination_concurrency_positive_feedback (1)
243              The per-destination  amount  of  delivery  concurrency  positive
244              feedback, after a delivery completes without connection or hand‐
245              shake failure.
246
247       transport_destination_concurrency_positive_feedback  ($default_destina‐
248       tion_concurrency_positive_feedback)
249              A  transport-specific  override for the default_destination_con‐
250              currency_positive_feedback parameter value, where  transport  is
251              the master.cf name of the message delivery transport.
252
253       destination_concurrency_feedback_debug (no)
254              Make  the queue manager's feedback algorithm verbose for perfor‐
255              mance analysis purposes.
256

RECIPIENT SCHEDULING CONTROLS

258       default_destination_recipient_limit (50)
259              The default maximal number of recipients per message delivery.
260
261       transport_destination_recipient_limit     ($default_destination_recipi‐
262       ent_limit)
263              A transport-specific override for the default_destination_recip‐
264              ient_limit parameter value, where  transport  is  the  master.cf
265              name of the message delivery transport.
266

OTHER RESOURCE AND RATE CONTROLS

268       minimal_backoff_time (300s)
269              The minimal time between attempts to deliver a deferred message;
270              prior to Postfix 2.4 the default value was 1000s.
271
272       maximal_backoff_time (4000s)
273              The maximal time between attempts to deliver a deferred message.
274
275       maximal_queue_lifetime (5d)
276              Consider a message as undeliverable, when delivery fails with  a
277              temporary error, and the time in the queue has reached the maxi‐
278              mal_queue_lifetime limit.
279
280       queue_run_delay (300s)
281              The time between deferred queue  scans  by  the  queue  manager;
282              prior to Postfix 2.4 the default value was 1000s.
283
284       transport_retry_time (60s)
285              The  time  between attempts by the Postfix queue manager to con‐
286              tact a malfunctioning message delivery transport.
287
288       Available in Postfix version 2.1 and later:
289
290       bounce_queue_lifetime (5d)
291              Consider a bounce message as undeliverable, when delivery  fails
292              with  a  temporary  error, and the time in the queue has reached
293              the bounce_queue_lifetime limit.
294
295       Available in Postfix version 2.5 and later:
296
297       default_destination_rate_delay (0s)
298              The default amount of delay that is inserted between  individual
299              message  deliveries  to  the  same destination and over the same
300              message delivery transport.
301
302       transport_destination_rate_delay ($default_destination_rate_delay)
303              A   transport-specific   override   for   the   default_destina‐
304              tion_rate_delay  parameter  value,  where  transport is the mas‐
305              ter.cf name of the message delivery transport.
306
307       Available in Postfix version 3.1 and later:
308
309       default_transport_rate_delay (0s)
310              The default amount of delay that is inserted between  individual
311              message  deliveries  over  the  same message delivery transport,
312              regardless of destination.
313
314       transport_transport_rate_delay ($default_transport_rate_delay)
315              A   transport-specific   override   for    the    default_trans‐
316              port_rate_delay  parameter value, where the initial transport in
317              the parameter name is the master.cf name of the message delivery
318              transport.
319

SAFETY CONTROLS

321       qmgr_daemon_timeout (1000s)
322              How much time a Postfix queue manager process may take to handle
323              a request before it is terminated by a built-in watchdog timer.
324
325       qmgr_ipc_timeout (60s)
326              The time limit for the queue manager to send or receive informa‐
327              tion over an internal communication channel.
328
329       Available in Postfix version 3.1 and later:
330
331       address_verify_pending_request_limit (see 'postconf -d' output)
332              A  safety limit that prevents address verification requests from
333              overwhelming the Postfix queue.
334

MISCELLANEOUS CONTROLS

336       config_directory (see 'postconf -d' output)
337              The default location of the Postfix main.cf and  master.cf  con‐
338              figuration files.
339
340       defer_transports (empty)
341              The names of message delivery transports that should not deliver
342              mail unless someone issues "sendmail -q" or equivalent.
343
344       delay_logging_resolution_limit (2)
345              The maximal number of digits after the decimal point  when  log‐
346              ging sub-second delay values.
347
348       helpful_warnings (yes)
349              Log  warnings about problematic configuration settings, and pro‐
350              vide helpful suggestions.
351
352       process_id (read-only)
353              The process ID of a Postfix command or daemon process.
354
355       process_name (read-only)
356              The process name of a Postfix command or daemon process.
357
358       queue_directory (see 'postconf -d' output)
359              The location of the Postfix top-level queue directory.
360
361       syslog_facility (mail)
362              The syslog facility of Postfix logging.
363
364       syslog_name (see 'postconf -d' output)
365              A prefix that  is  prepended  to  the  process  name  in  syslog
366              records, so that, for example, "smtpd" becomes "prefix/smtpd".
367
368       Available in Postfix version 3.0 and later:
369
370       confirm_delay_cleared (no)
371              After  sending  a "your message is delayed" notification, inform
372              the sender when the delay clears up.
373
374       Available in Postfix 3.3 and later:
375
376       service_name (read-only)
377              The master.cf service name of a Postfix daemon process.
378

FILES

380       /var/spool/postfix/incoming, incoming queue
381       /var/spool/postfix/active, active queue
382       /var/spool/postfix/deferred, deferred queue
383       /var/spool/postfix/bounce, non-delivery status
384       /var/spool/postfix/defer, non-delivery status
385       /var/spool/postfix/trace, delivery status
386

SEE ALSO

388       trivial-rewrite(8), address routing
389       bounce(8), delivery status reports
390       postconf(5), configuration parameters
391       master(5), generic daemon options
392       master(8), process manager
393       postlogd(8), Postfix logging
394       syslogd(8), system logging
395

README FILES

397       Use "postconf readme_directory" or "postconf html_directory" to  locate
398       this information.
399       QSHAPE_README, Postfix queue analysis
400

LICENSE

402       The Secure Mailer license must be distributed with this software.
403

AUTHOR(S)

405       Wietse Venema
406       IBM T.J. Watson Research
407       P.O. Box 704
408       Yorktown Heights, NY 10598, USA
409
410       Wietse Venema
411       Google, Inc.
412       111 8th Avenue
413       New York, NY 10011, USA
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415
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417                                                                      OQMGR(8)
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