# phpman > man > master(8postfix) [MASTER(8postfix)](https://www.chedong.com/phpMan.php/man/MASTER/8postfix/markdown) [MASTER(8postfix)](https://www.chedong.com/phpMan.php/man/MASTER/8postfix/markdown) ## NAME master - Postfix master process ## SYNOPSIS **master** [**-Dditvw**] [**-c** _config_dir_] [**-e** _exit_time_] ## DESCRIPTION The [**master**(8)](https://www.chedong.com/phpMan.php/man/master/8/markdown) daemon is the resident process that runs Postfix daemons on demand: daemons to send or receive messages via the network, daemons to deliver mail locally, etc. These dae‐ mons are created on demand up to a configurable maximum number per service. Postfix daemons terminate voluntarily, either after being idle for a configurable amount of time, or after having serviced a configurable number of requests. Exceptions to this rule are the resident queue manager, address verification server, and the TLS session cache and pseudo-random number server. The behavior of the [**master**(8)](https://www.chedong.com/phpMan.php/man/master/8/markdown) daemon is controlled by the **master.cf** configuration file, as described in [**master**(5)](https://www.chedong.com/phpMan.php/man/master/5/markdown). Options: ### -c Read the **main.cf** and **master.cf** configuration files in the named directory instead of the default configuration directory. This also overrides the configuration files for other Postfix daemon processes. ### -D specified with the **debugger**___**command** in the **main.cf** global configuration file. ### -d ling terminal. This must be used for debugging only. ### -e Terminate the master process after _exit_time_ seconds. Child processes terminate at their convenience. ### -i -s do not redirect stdout to /dev/null, so that "maillog_file = /dev/stdout" works. This mode is allowed only if the process ID equals 1. This feature is available in Postfix 3.3 and later. ### -s This feature is available in Postfix 3.4 and later. ### -t when that file is not locked. This is evidence that the [**master**(8)](https://www.chedong.com/phpMan.php/man/master/8/markdown) daemon is not run‐ ning. ### -v cesses. Multiple **-v** options make the software increasingly verbose. ### -w background process. The dummy foreground process returns a zero exit status only if the master daemon initialization is successful, and if it completes in a reasonable amount of time. This feature is available in Postfix 2.10 and later. Signals: **SIGHUP** Upon receipt of a **HUP** signal (e.g., after "**postfix** **reload**"), the master process re-reads its configuration files. If a service has been removed from the **master.cf** file, its running processes are terminated immediately. Otherwise, running processes are allowed to terminate as soon as is convenient, so that changes in configuration settings affect only new service requests. **SIGTERM** Upon receipt of a **TERM** signal (e.g., after "**postfix** **abort**"), the master process passes the signal on to its child processes and terminates. This is useful for an emergency shutdown. Normally one would terminate only the master ("**postfix** **stop**") and allow run‐ ning processes to finish what they are doing. ## DIAGNOSTICS Problems are reported to [**syslogd**(8)](https://www.chedong.com/phpMan.php/man/syslogd/8/markdown) or [**postlogd**(8)](https://www.chedong.com/phpMan.php/man/postlogd/8/markdown). The exit status is non-zero in case of problems, including problems while initializing as a master daemon process in the background. ## ENVIRONMENT **MAIL**___**DEBUG** After initialization, start a debugger as specified with the **debugger**___**command** configu‐ ration parameter in the **main.cf** configuration file. **MAIL**___**CONFIG** Directory with Postfix configuration files. ## CONFIGURATION PARAMETERS Unlike most Postfix daemon processes, the [**master**(8)](https://www.chedong.com/phpMan.php/man/master/8/markdown) server does not automatically pick up changes to **main.cf**. Changes to **master.cf** are never picked up automatically. Use the "**postfix** **reload**" command after a configuration change. ## RESOURCE AND RATE CONTROLS **default**___**process**___**limit** **(100)** The default maximal number of Postfix child processes that provide a given service. **max**___**idle** **(100s)** The maximum amount of time that an idle Postfix daemon process waits for an incoming connection before terminating voluntarily. **max**___**use** **(100)** The maximal number of incoming connections that a Postfix daemon process will service before terminating voluntarily. **service**___**throttle**___**time** **(60s)** How long the Postfix [**master**(8)](https://www.chedong.com/phpMan.php/man/master/8/markdown) waits before forking a server that appears to be mal‐ functioning. Available in Postfix version 2.6 and later: **master**___**service**___**disable** **(empty)** Selectively disable [**master**(8)](https://www.chedong.com/phpMan.php/man/master/8/markdown) listener ports by service type or by service name and type. ## MISCELLANEOUS CONTROLS **config**___**directory** **(see** **'postconf** **-d'** **output)** The default location of the Postfix main.cf and master.cf configuration files. **daemon**___**directory** **(see** **'postconf** **-d'** **output)** The directory with Postfix support programs and daemon programs. **debugger**___**command** **(empty)** The external command to execute when a Postfix daemon program is invoked with the -D option. **inet**___**interfaces** **(all)** The network interface addresses that this mail system receives mail on. **inet**___**protocols** **(see** **'postconf** **-d** **output')** The Internet protocols Postfix will attempt to use when making or accepting connec‐ tions. **import**___**environment** **(see** **'postconf** **-d'** **output)** The list of environment parameters that a privileged Postfix process will import from a non-Postfix parent process, or name=value environment overrides. **mail**___**owner** **(postfix)** The UNIX system account that owns the Postfix queue and most Postfix daemon processes. **process**___**id** **(read-only)** The process ID of a Postfix command or daemon process. **process**___**name** **(read-only)** The process name of a Postfix command or daemon process. **queue**___**directory** **(see** **'postconf** **-d'** **output)** The location of the Postfix top-level queue directory. **syslog**___**facility** **(mail)** The syslog facility of Postfix logging. **syslog**___**name** **(see** **'postconf** **-d'** **output)** A prefix that is prepended to the process name in syslog records, so that, for exam‐ ple, "smtpd" becomes "prefix/smtpd". Available in Postfix 3.3 and later: **service**___**name** **(read-only)** The master.cf service name of a Postfix daemon process. Available in Postfix 3.6 and later: **known**___**tcp**___**ports** **(lmtp=24,** **smtp=25,** **smtps=submissions=465,** **submission=587)** Optional setting that avoids lookups in the [**services**(5)](https://www.chedong.com/phpMan.php/man/services/5/markdown) database. ## FILES To expand the directory names below into their actual values, use the command "**postconf** **con**‐‐ **fig**___**directory**" etc. $config_directory/main.cf, global configuration file. $config_directory/master.cf, master server configuration file. $queue_directory/pid/master.pid, master lock file. $data_directory/master.lock, master lock file. ## SEE ALSO [qmgr(8)](https://www.chedong.com/phpMan.php/man/qmgr/8/markdown), queue manager [verify(8)](https://www.chedong.com/phpMan.php/man/verify/8/markdown), address verification [master(5)](https://www.chedong.com/phpMan.php/man/master/5/markdown), master.cf configuration file syntax [postconf(5)](https://www.chedong.com/phpMan.php/man/postconf/5/markdown), main.cf configuration file syntax [postlogd(8)](https://www.chedong.com/phpMan.php/man/postlogd/8/markdown), Postfix logging [syslogd(8)](https://www.chedong.com/phpMan.php/man/syslogd/8/markdown), system logging ## LICENSE The Secure Mailer license must be distributed with this software. **AUTHOR(S)** Wietse Venema IBM T.J. Watson Research P.O. Box 704 Yorktown Heights, NY 10598, USA Wietse Venema Google, Inc. 111 8th Avenue New York, NY 10011, USA [MASTER(8postfix)](https://www.chedong.com/phpMan.php/man/MASTER/8postfix/markdown)