.\" $NetBSD: master.8,v 1.2.14.1 2023/12/25 12:54:41 martin Exp $ .\" .TH MASTER 8 .ad .fi .SH NAME master \- Postfix master process .SH "SYNOPSIS" .na .nf \fBmaster\fR [\fB\-Dditvw\fR] [\fB\-c \fIconfig_dir\fR] [\fB\-e \fIexit_time\fR] .SH DESCRIPTION .ad .fi The \fBmaster\fR(8) 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 daemons 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 \fBmaster\fR(8) daemon is controlled by the \fBmaster.cf\fR configuration file, as described in \fBmaster\fR(5). Options: .IP "\fB\-c \fIconfig_dir\fR" Read the \fBmain.cf\fR and \fBmaster.cf\fR configuration files in the named directory instead of the default configuration directory. This also overrides the configuration files for other Postfix daemon processes. .IP \fB\-D\fR After initialization, run a debugger on the master process. The debugging command is specified with the \fBdebugger_command\fR in the \fBmain.cf\fR global configuration file. .IP \fB\-d\fR Do not redirect stdin, stdout or stderr to /dev/null, and do not discard the controlling terminal. This must be used for debugging only. .IP "\fB\-e \fIexit_time\fR" Terminate the master process after \fIexit_time\fR seconds. Child processes terminate at their convenience. .IP \fB\-i\fR Enable \fBinit\fR mode: do not become a session or process group leader; and similar to \fB\-s\fR, 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. .sp This feature is available in Postfix 3.3 and later. .IP \fB\-s\fR Do not redirect stdout to /dev/null, so that "maillog_file = /dev/stdout" works. .sp This feature is available in Postfix 3.4 and later. .IP \fB\-t\fR Test mode. Return a zero exit status when the \fBmaster.pid\fR lock file does not exist or when that file is not locked. This is evidence that the \fBmaster\fR(8) daemon is not running. .IP \fB\-v\fR Enable verbose logging for debugging purposes. This option is passed on to child processes. Multiple \fB\-v\fR options make the software increasingly verbose. .IP \fB\-w\fR Wait in a dummy foreground process, while the real master daemon initializes in a 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. .sp This feature is available in Postfix 2.10 and later. .PP Signals: .IP \fBSIGHUP\fR Upon receipt of a \fBHUP\fR signal (e.g., after "\fBpostfix reload\fR"), the master process re\-reads its configuration files. If a service has been removed from the \fBmaster.cf\fR 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. .IP \fBSIGTERM\fR Upon receipt of a \fBTERM\fR signal (e.g., after "\fBpostfix abort\fR"), 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 ("\fBpostfix stop\fR") and allow running processes to finish what they are doing. .SH DIAGNOSTICS .ad .fi Problems are reported to \fBsyslogd\fR(8) or \fBpostlogd\fR(8). The exit status is non\-zero in case of problems, including problems while initializing as a master daemon process in the background. .SH "ENVIRONMENT" .na .nf .ad .fi .IP \fBMAIL_DEBUG\fR After initialization, start a debugger as specified with the \fBdebugger_command\fR configuration parameter in the \fBmain.cf\fR configuration file. .IP \fBMAIL_CONFIG\fR Directory with Postfix configuration files. .SH "CONFIGURATION PARAMETERS" .na .nf .ad .fi Unlike most Postfix daemon processes, the \fBmaster\fR(8) server does not automatically pick up changes to \fBmain.cf\fR. Changes to \fBmaster.cf\fR are never picked up automatically. Use the "\fBpostfix reload\fR" command after a configuration change. .SH "RESOURCE AND RATE CONTROLS" .na .nf .ad .fi .IP "\fBdefault_process_limit (100)\fR" The default maximal number of Postfix child processes that provide a given service. .IP "\fBmax_idle (100s)\fR" The maximum amount of time that an idle Postfix daemon process waits for an incoming connection before terminating voluntarily. .IP "\fBmax_use (100)\fR" The maximal number of incoming connections that a Postfix daemon process will service before terminating voluntarily. .IP "\fBservice_throttle_time (60s)\fR" How long the Postfix \fBmaster\fR(8) waits before forking a server that appears to be malfunctioning. .PP Available in Postfix version 2.6 and later: .IP "\fBmaster_service_disable (empty)\fR" Selectively disable \fBmaster\fR(8) listener ports by service type or by service name and type. .SH "MISCELLANEOUS CONTROLS" .na .nf .ad .fi .IP "\fBconfig_directory (see 'postconf -d' output)\fR" The default location of the Postfix main.cf and master.cf configuration files. .IP "\fBdaemon_directory (see 'postconf -d' output)\fR" The directory with Postfix support programs and daemon programs. .IP "\fBdebugger_command (empty)\fR" The external command to execute when a Postfix daemon program is invoked with the \-D option. .IP "\fBinet_interfaces (all)\fR" The network interface addresses that this mail system receives mail on. .IP "\fBinet_protocols (see 'postconf -d output')\fR" The Internet protocols Postfix will attempt to use when making or accepting connections. .IP "\fBimport_environment (see 'postconf -d' output)\fR" The list of environment parameters that a privileged Postfix process will import from a non\-Postfix parent process, or name=value environment overrides. .IP "\fBmail_owner (postfix)\fR" The UNIX system account that owns the Postfix queue and most Postfix daemon processes. .IP "\fBprocess_id (read\-only)\fR" The process ID of a Postfix command or daemon process. .IP "\fBprocess_name (read\-only)\fR" The process name of a Postfix command or daemon process. .IP "\fBqueue_directory (see 'postconf -d' output)\fR" The location of the Postfix top\-level queue directory. .IP "\fBsyslog_facility (mail)\fR" The syslog facility of Postfix logging. .IP "\fBsyslog_name (see 'postconf -d' output)\fR" A prefix that is prepended to the process name in syslog records, so that, for example, "smtpd" becomes "prefix/smtpd". .PP Available in Postfix 3.3 and later: .IP "\fBservice_name (read\-only)\fR" The master.cf service name of a Postfix daemon process. .PP Available in Postfix 3.6 and later: .IP "\fBknown_tcp_ports (lmtp=24, smtp=25, smtps=submissions=465, submission=587)\fR" Optional setting that avoids lookups in the \fBservices\fR(5) database. .SH "FILES" .na .nf .ad .fi To expand the directory names below into their actual values, use the command "\fBpostconf config_directory\fR" etc. .na .nf $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. .SH "SEE ALSO" .na .nf qmgr(8), queue manager verify(8), address verification master(5), master.cf configuration file syntax postconf(5), main.cf configuration file syntax postlogd(8), Postfix logging syslogd(8), system logging .SH "LICENSE" .na .nf .ad .fi The Secure Mailer license must be distributed with this software. .SH "AUTHOR(S)" .na .nf 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