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

6       master - Postfix master process
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SYNOPSIS

9       master [-Ddtvw] [-c config_dir] [-e exit_time]
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DESCRIPTION

12       The  master(8) daemon is the resident process that runs Postfix daemons
13       on demand: daemons to send or receive messages via the network, daemons
14       to  deliver  mail locally, etc.  These daemons are created on demand up
15       to a configurable maximum number per service.
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17       Postfix daemons terminate voluntarily, either after being  idle  for  a
18       configurable  amount  of  time, or after having serviced a configurable
19       number of requests. Exceptions to this rule are the resident queue man‐
20       ager,  address  verification  server,  and  the  TLS  session cache and
21       pseudo-random number server.
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23       The behavior of the master(8) daemon is  controlled  by  the  master.cf
24       configuration file, as described in master(5).
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26       Options:
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28       -c config_dir
29              Read  the main.cf and master.cf configuration files in the named
30              directory instead of the default configuration directory.   This
31              also  overrides the configuration files for other Postfix daemon
32              processes.
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34       -D     After initialization, run a debugger on the master process.  The
35              debugging  command is specified with the debugger_command in the
36              main.cf global configuration file.
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38       -d     Do not redirect stdin, stdout or stderr to /dev/null, and do not
39              discard  the  controlling terminal. This must be used for debug‐
40              ging only.
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42       -e exit_time
43              Terminate the master process after exit_time seconds. Child pro‐
44              cesses terminate at their convenience.
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46       -t     Test  mode.  Return  a zero exit status when the master.pid lock
47              file does not exist or when that file is not  locked.   This  is
48              evidence that the master(8) daemon is not running.
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50       -v     Enable  verbose  logging  for debugging purposes. This option is
51              passed on to child processes. Multiple -v options make the soft‐
52              ware increasingly verbose.
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54       -w     Wait in a dummy foreground process, while the real master daemon
55              initializes in  a  background  process.   The  dummy  foreground
56              process  returns  a  zero  exit status only if the master daemon
57              initialization is successful, and if it completes in  a  reason‐
58              able amount of time.
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60              This feature is available in Postfix 2.10 and later.
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62       Signals:
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64       SIGHUP Upon receipt of a HUP signal (e.g., after "postfix reload"), the
65              master process re-reads its configuration files.  If  a  service
66              has  been removed from the master.cf file, its running processes
67              are terminated immediately.  Otherwise,  running  processes  are
68              allowed  to  terminate as soon as is convenient, so that changes
69              in configuration settings affect only new service requests.
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71       SIGTERM
72              Upon receipt of a TERM signal (e.g., after "postfix abort"), the
73              master  process  passes the signal on to its child processes and
74              terminates.  This is useful for an emergency shutdown.  Normally
75              one  would  terminate only the master ("postfix stop") and allow
76              running processes to finish what they are doing.
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DIAGNOSTICS

79       Problems are reported to syslogd(8). The exit  status  is  non-zero  in
80       case  of  problems,  including  problems while initializing as a master
81       daemon process in the background.
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ENVIRONMENT

84       MAIL_DEBUG
85              After initialization, start a debugger  as  specified  with  the
86              debugger_command configuration parameter in the main.cf configu‐
87              ration file.
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89       MAIL_CONFIG
90              Directory with Postfix configuration files.
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CONFIGURATION PARAMETERS

93       Unlike most Postfix daemon processes, the  master(8)  server  does  not
94       automatically  pick  up  changes  to  main.cf. Changes to master.cf are
95       never picked up automatically.  Use the "postfix reload" command  after
96       a configuration change.
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RESOURCE AND RATE CONTROLS

99       default_process_limit (100)
100              The  default maximal number of Postfix child processes that pro‐
101              vide a given service.
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103       max_idle (100s)
104              The maximum amount of time that an idle Postfix  daemon  process
105              waits for an incoming connection before terminating voluntarily.
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107       max_use (100)
108              The maximal number of incoming connections that a Postfix daemon
109              process will service before terminating voluntarily.
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111       service_throttle_time (60s)
112              How long the Postfix master(8) waits  before  forking  a  server
113              that appears to be malfunctioning.
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115       Available in Postfix version 2.6 and later:
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117       master_service_disable (empty)
118              Selectively  disable master(8) listener ports by service type or
119              by service name and type.
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MISCELLANEOUS CONTROLS

122       config_directory (see 'postconf -d' output)
123              The default location of the Postfix main.cf and  master.cf  con‐
124              figuration files.
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126       daemon_directory (see 'postconf -d' output)
127              The directory with Postfix support programs and daemon programs.
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129       debugger_command (empty)
130              The external command to execute when a Postfix daemon program is
131              invoked with the -D option.
132
133       inet_interfaces (all)
134              The network interface addresses that this mail  system  receives
135              mail on.
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137       inet_protocols (all)
138              The  Internet  protocols Postfix will attempt to use when making
139              or accepting connections.
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141       import_environment (see 'postconf -d' output)
142              The list of environment parameters that a Postfix  process  will
143              import from a non-Postfix parent process.
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145       mail_owner (postfix)
146              The  UNIX  system  account  that owns the Postfix queue and most
147              Postfix daemon processes.
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149       process_id (read-only)
150              The process ID of a Postfix command or daemon process.
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152       process_name (read-only)
153              The process name of a Postfix command or daemon process.
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155       queue_directory (see 'postconf -d' output)
156              The location of the Postfix top-level queue directory.
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158       syslog_facility (mail)
159              The syslog facility of Postfix logging.
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161       syslog_name (see 'postconf -d' output)
162              The mail system name that is prepended to the  process  name  in
163              syslog  records,  so  that  "smtpd" becomes, for example, "post‐
164              fix/smtpd".
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FILES

167       To expand the directory names below into their actual values,  use  the
168       command "postconf config_directory" etc.
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170       $config_directory/main.cf, global configuration file.
171       $config_directory/master.cf, master server configuration file.
172       $queue_directory/pid/master.pid, master lock file.
173       $data_directory/master.lock, master lock file.
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SEE ALSO

176       qmgr(8), queue manager
177       verify(8), address verification
178       master(5), master.cf configuration file syntax
179       postconf(5), main.cf configuration file syntax
180       syslogd(8), system logging
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LICENSE

183       The Secure Mailer license must be distributed with this software.
184

AUTHOR(S)

186       Wietse Venema
187       IBM T.J. Watson Research
188       P.O. Box 704
189       Yorktown Heights, NY 10598, USA
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