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 [-Dditvw] [-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.
16
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.
33
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.
41
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       -i     Enable  init  mode:  do  not  become  a session or process group
47              leader; and similar to -s, do not redirect stdout to  /dev/null,
48              so  that  "maillog_file  = /dev/stdout" works.  This mode is al‐
49              lowed only if the process ID equals 1.
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51              This feature is available in Postfix 3.3 and later.
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53       -s     Do not redirect stdout to /dev/null,  so  that  "maillog_file  =
54              /dev/stdout" works.
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56              This feature is available in Postfix 3.4 and later.
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58       -t     Test  mode.  Return  a zero exit status when the master.pid lock
59              file does not exist or when that file is not  locked.   This  is
60              evidence that the master(8) daemon is not running.
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62       -v     Enable  verbose  logging  for debugging purposes. This option is
63              passed on to child processes. Multiple -v options make the soft‐
64              ware increasingly verbose.
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66       -w     Wait in a dummy foreground process, while the real master daemon
67              initializes in  a  background  process.   The  dummy  foreground
68              process  returns  a  zero  exit status only if the master daemon
69              initialization is successful, and if it completes in  a  reason‐
70              able amount of time.
71
72              This feature is available in Postfix 2.10 and later.
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74       Signals:
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76       SIGHUP Upon receipt of a HUP signal (e.g., after "postfix reload"), the
77              master process re-reads its configuration files.  If  a  service
78              has  been removed from the master.cf file, its running processes
79              are terminated immediately.  Otherwise,  running  processes  are
80              allowed  to  terminate as soon as is convenient, so that changes
81              in configuration settings affect only new service requests.
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83       SIGTERM
84              Upon receipt of a TERM signal (e.g., after "postfix abort"), the
85              master  process  passes the signal on to its child processes and
86              terminates.  This is useful for an emergency shutdown.  Normally
87              one  would  terminate only the master ("postfix stop") and allow
88              running processes to finish what they are doing.
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DIAGNOSTICS

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

96       MAIL_DEBUG
97              After initialization, start a debugger as specified with the de‐
98              bugger_command configuration parameter in the main.cf configura‐
99              tion file.
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101       MAIL_CONFIG
102              Directory with Postfix configuration files.
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CONFIGURATION PARAMETERS

105       Unlike most Postfix daemon processes, the master(8) server does not au‐
106       tomatically  pick up changes to main.cf. Changes to master.cf are never
107       picked up automatically.  Use the "postfix reload" command after a con‐
108       figuration change.
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RESOURCE AND RATE CONTROLS

111       default_process_limit (100)
112              The  default maximal number of Postfix child processes that pro‐
113              vide a given service.
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115       max_idle (100s)
116              The maximum amount of time that an idle Postfix  daemon  process
117              waits for an incoming connection before terminating voluntarily.
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119       max_use (100)
120              The maximal number of incoming connections that a Postfix daemon
121              process will service before terminating voluntarily.
122
123       service_throttle_time (60s)
124              How long the Postfix master(8) waits  before  forking  a  server
125              that appears to be malfunctioning.
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127       Available in Postfix version 2.6 and later:
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129       master_service_disable (empty)
130              Selectively  disable master(8) listener ports by service type or
131              by service name and type.
132

MISCELLANEOUS CONTROLS

134       config_directory (see 'postconf -d' output)
135              The default location of the Postfix main.cf and  master.cf  con‐
136              figuration files.
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138       daemon_directory (see 'postconf -d' output)
139              The directory with Postfix support programs and daemon programs.
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141       debugger_command (empty)
142              The external command to execute when a Postfix daemon program is
143              invoked with the -D option.
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145       inet_interfaces (all)
146              The network interface addresses that this mail  system  receives
147              mail on.
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149       inet_protocols (see 'postconf -d output')
150              The  Internet  protocols Postfix will attempt to use when making
151              or accepting connections.
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153       import_environment (see 'postconf -d' output)
154              The list of environment parameters  that  a  privileged  Postfix
155              process  will  import  from  a  non-Postfix  parent  process, or
156              name=value environment overrides.
157
158       mail_owner (postfix)
159              The UNIX system account that owns the  Postfix  queue  and  most
160              Postfix daemon processes.
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162       process_id (read-only)
163              The process ID of a Postfix command or daemon process.
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165       process_name (read-only)
166              The process name of a Postfix command or daemon process.
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168       queue_directory (see 'postconf -d' output)
169              The location of the Postfix top-level queue directory.
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171       syslog_facility (mail)
172              The syslog facility of Postfix logging.
173
174       syslog_name (see 'postconf -d' output)
175              A  prefix  that  is  prepended  to  the  process  name in syslog
176              records, so that, for example, "smtpd" becomes "prefix/smtpd".
177
178       Available in Postfix 3.3 and later:
179
180       service_name (read-only)
181              The master.cf service name of a Postfix daemon process.
182
183       Available in Postfix 3.6 and later:
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185       known_tcp_ports  (lmtp=24,  smtp=25,   smtps=submissions=465,   submis‐
186       sion=587)
187              Optional  setting  that  avoids lookups in the services(5) data‐
188              base.
189

FILES

191       To expand the directory names below into their actual values,  use  the
192       command "postconf config_directory" etc.
193
194       $config_directory/main.cf, global configuration file.
195       $config_directory/master.cf, master server configuration file.
196       $queue_directory/pid/master.pid, master lock file.
197       $data_directory/master.lock, master lock file.
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SEE ALSO

200       qmgr(8), queue manager
201       verify(8), address verification
202       master(5), master.cf configuration file syntax
203       postconf(5), main.cf configuration file syntax
204       postlogd(8), Postfix logging
205       syslogd(8), system logging
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LICENSE

208       The Secure Mailer license must be distributed with this software.
209

AUTHOR(S)

211       Wietse Venema
212       IBM T.J. Watson Research
213       P.O. Box 704
214       Yorktown Heights, NY 10598, USA
215
216       Wietse Venema
217       Google, Inc.
218       111 8th Avenue
219       New York, NY 10011, USA
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