MASTER(8)		    System Manager's Manual		     MASTER(8)



NAME
       master - Postfix master process

SYNOPSIS
       master [-Ddtv] [-c config_dir] [-e exit_time]

DESCRIPTION
       The  master(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 man-
       ager,  address  verification  server,  and  the	TLS  session cache and
       pseudo-random number server.

       The behavior of the master(8) daemon is	controlled  by	the  master.cf
       configuration file, as described in master(5).

       Options:

       -c config_dir
	      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     After initialization, run a debugger on the master process.  The
	      debugging	 command is specified with the debugger_command in the
	      main.cf global configuration file.

       -d     Do not redirect stdin, stdout or stderr to /dev/null, and do not
	      discard  the  controlling terminal. This must be used for debug-
	      ging only.

       -e exit_time
	      Terminate the master process after exit_time seconds. Child pro-
	      cesses terminate at their convenience.

       -t     Test  mode.  Return  a zero exit status when the master.pid lock
	      file does not exist or when that file is not  locked.   This  is
	      evidence that the master(8) daemon is not running.

       -v     Enable  verbose  logging	for debugging purposes. This option is
	      passed on to child processes. Multiple -v options make the soft-
	      ware increasingly verbose.

       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
	      running processes to finish what they are doing.

DIAGNOSTICS
       Problems are reported to syslogd(8).

ENVIRONMENT
       MAIL_DEBUG
	      After initialization, start a debugger  as  specified  with  the
	      debugger_command configuration parameter in the main.cf configu-
	      ration file.

       MAIL_CONFIG
	      Directory with Postfix configuration files.

CONFIGURATION PARAMETERS
       Unlike most Postfix daemon processes, the  master(8)  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 pro-
	      vide 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) waits  before  forking  a	server
	      that appears to be malfunctioning.

       Available in Postfix version 2.6 and later:

       master_service_disable (empty)
	      Selectively  disable master(8) 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  con-
	      figuration 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 (ipv4)
	      The  Internet  protocols Postfix will attempt to use when making
	      or accepting connections.

       import_environment (see 'postconf -d' output)
	      The list of environment parameters that a Postfix	 process  will
	      import from a non-Postfix parent process.

       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)
	      The mail system name that is prepended to the  process  name  in
	      syslog  records,	so  that  "smtpd" becomes, for example, "post-
	      fix/smtpd".

FILES
       To expand the directory names below into their actual values,  use  the
       command "postconf config_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), queue manager
       verify(8), address verification
       master(5), master.cf configuration file syntax
       postconf(5), main.cf configuration parameter syntax
       syslogd(8), 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



								     MASTER(8)