MASTER(8postfix)                                                                 MASTER(8postfix)



NAME
       master - Postfix master process

SYNOPSIS
       master [-Ddtvw] [-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  manager, 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  con‐
              trolling terminal. This must be used for debugging only.

       -e exit_time
              Terminate  the master process after exit_time seconds. Child processes 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 software increasingly verbose.

       -w     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 reason‐
              able 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  pro‐
              cesses  are  allowed to terminate as soon as is convenient, so that changes in con‐
              figuration 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).  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  con‐
              figuration parameter in the main.cf configuration 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 provide a given service.

       max_idle (100s)
              The  maximum amount of time that an idle Postfix daemon process waits for an incom‐
              ing connection before terminating voluntarily.

       max_use (100)
              The maximal number of incoming connections that a Postfix daemon process will  ser‐
              vice 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 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 (all)
              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 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  pro‐
              cesses.

       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, "postfix/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 file 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(8postfix)