1MASTER(8) System Manager's Manual MASTER(8)
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6 master - Postfix master process
7
9 master [-Ddtvw] [-c config_dir] [-e exit_time]
10
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 -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.
59 This feature is available in Postfix 2.10 and later.
61 Signals:
63 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.
70 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.
77
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.
82
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.
88 MAIL_CONFIG
90 Directory with Postfix configuration files.
91
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.
97
99 default_process_limit (100)
100 The default maximal number of Postfix child processes that pro‐
101 vide a given service.
102 max_idle (100s)
104 The maximum amount of time that an idle Postfix daemon process
105 waits for an incoming connection before terminating voluntarily.
106 max_use (100)
108 The maximal number of incoming connections that a Postfix daemon
109 process will service before terminating voluntarily.
110 service_throttle_time (60s)
112 How long the Postfix master(8) waits before forking a server
113 that appears to be malfunctioning.
114 Available in Postfix version 2.6 and later:
116 master_service_disable (empty)
118 Selectively disable master(8) listener ports by service type or
119 by service name and type.
120
122 config_directory (see 'postconf -d' output)
123 The default location of the Postfix main.cf and master.cf con‐
124 figuration files.
125 daemon_directory (see 'postconf -d' output)
127 The directory with Postfix support programs and daemon programs.
128 debugger_command (empty)
130 The external command to execute when a Postfix daemon program is
131 invoked with the -D option.
132 inet_interfaces (all)
134 The network interface addresses that this mail system receives
135 mail on.
136 inet_protocols (all)
138 The Internet protocols Postfix will attempt to use when making
139 or accepting connections.
140 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.
144 mail_owner (postfix)
146 The UNIX system account that owns the Postfix queue and most
147 Postfix daemon processes.
148 process_id (read-only)
150 The process ID of a Postfix command or daemon process.
151 process_name (read-only)
153 The process name of a Postfix command or daemon process.
154 queue_directory (see 'postconf -d' output)
156 The location of the Postfix top-level queue directory.
157 syslog_facility (mail)
159 The syslog facility of Postfix logging.
160 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".
165
167 To expand the directory names below into their actual values, use the
168 command "postconf config_directory" etc.
169 $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.
174
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
181
183 The Secure Mailer license must be distributed with this software.
184
186 Wietse Venema
187 IBM T.J. Watson Research
188 P.O. Box 704
189 Yorktown Heights, NY 10598, USA
190 MASTER(8)