1MASTER(8) System Manager's Manual MASTER(8)
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6 master - Postfix master process
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9 master [-Ddtv] [-c config_dir] [-e exit_time]
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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 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.
22 The behavior of the master(8) daemon is controlled by the master.cf
24 configuration file, as described in master(5).
25 Options:
27 -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 -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.
37 -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 -e exit_time
43 Terminate the master process after exit_time seconds. Child pro‐
44 cesses terminate at their convenience.
45 -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.
49 -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.
53 Signals:
55 SIGHUP Upon receipt of a HUP signal (e.g., after "postfix reload"), the
57 master process re-reads its configuration files. If a service
58 has been removed from the master.cf file, its running processes
59 are terminated immediately. Otherwise, running processes are
60 allowed to terminate as soon as is convenient, so that changes
61 in configuration settings affect only new service requests.
62 SIGTERM
64 Upon receipt of a TERM signal (e.g., after "postfix abort"), the
65 master process passes the signal on to its child processes and
66 terminates. This is useful for an emergency shutdown. Normally
67 one would terminate only the master ("postfix stop") and allow
68 running processes to finish what they are doing.
69
71 Problems are reported to syslogd(8).
72
74 MAIL_DEBUG
75 After initialization, start a debugger as specified with the
76 debugger_command configuration parameter in the main.cf configu‐
77 ration file.
78 MAIL_CONFIG
80 Directory with Postfix configuration files.
81
83 Unlike most Postfix daemon processes, the master(8) server does not
84 automatically pick up changes to main.cf. Changes to master.cf are
85 never picked up automatically. Use the "postfix reload" command after
86 a configuration change.
87
89 default_process_limit (100)
90 The default maximal number of Postfix child processes that pro‐
91 vide a given service.
92 max_idle (100s)
94 The maximum amount of time that an idle Postfix daemon process
95 waits for an incoming connection before terminating voluntarily.
96 max_use (100)
98 The maximal number of incoming connections that a Postfix daemon
99 process will service before terminating voluntarily.
100 service_throttle_time (60s)
102 How long the Postfix master(8) waits before forking a server
103 that appears to be malfunctioning.
104 Available in Postfix version 2.6 and later:
106 master_service_disable (empty)
108 Selectively disable master(8) listener ports by service type or
109 by service name and type.
110
112 config_directory (see 'postconf -d' output)
113 The default location of the Postfix main.cf and master.cf con‐
114 figuration files.
115 daemon_directory (see 'postconf -d' output)
117 The directory with Postfix support programs and daemon programs.
118 debugger_command (empty)
120 The external command to execute when a Postfix daemon program is
121 invoked with the -D option.
122 inet_interfaces (all)
124 The network interface addresses that this mail system receives
125 mail on.
126 inet_protocols (ipv4)
128 The Internet protocols Postfix will attempt to use when making
129 or accepting connections.
130 import_environment (see 'postconf -d' output)
132 The list of environment parameters that a Postfix process will
133 import from a non-Postfix parent process.
134 mail_owner (postfix)
136 The UNIX system account that owns the Postfix queue and most
137 Postfix daemon processes.
138 process_id (read-only)
140 The process ID of a Postfix command or daemon process.
141 process_name (read-only)
143 The process name of a Postfix command or daemon process.
144 queue_directory (see 'postconf -d' output)
146 The location of the Postfix top-level queue directory.
147 syslog_facility (mail)
149 The syslog facility of Postfix logging.
150 syslog_name (see 'postconf -d' output)
152 The mail system name that is prepended to the process name in
153 syslog records, so that "smtpd" becomes, for example, "post‐
154 fix/smtpd".
155
157 To expand the directory names below into their actual values, use the
158 command "postconf config_directory" etc.
159 $config_directory/main.cf, global configuration file.
161 $config_directory/master.cf, master server configuration file.
162 $queue_directory/pid/master.pid, master lock file.
163 $data_directory/master.lock, master lock file.
164
166 qmgr(8), queue manager
167 verify(8), address verification
168 master(5), master.cf configuration file syntax
169 postconf(5), main.cf configuration parameter syntax
170 syslogd(8), system logging
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173 The Secure Mailer license must be distributed with this software.
174
176 Wietse Venema
177 IBM T.J. Watson Research
178 P.O. Box 704
179 Yorktown Heights, NY 10598, USA
180 MASTER(8)