MASTER(8)                                                            MASTER(8)

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 mes-
       sages  via  the  network, daemons to deliver mail locally,
       etc.  These daemons are created on demand up to a  config-
       urable 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  verifi-
       cation 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  con-
              figuration directory.  This also overrides the con-
              figuration files  for  other  Postfix  daemon  pro-
              cesses.

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

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

       -e exit_time
              Terminate the master process after  exit_time  sec-
              onds.  Child  processes  terminate  at their conve-
              nience.

       -t     Test mode. Return a zero exit status when the  mas-
              ter.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 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  configu-
              ration  files.  If  a service has been removed from
              the master.cf file, its running processes are  ter-
              minated  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 ter-
              minate 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 configuration 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 pro-
              cesses 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 termi-
              nating 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 dae-
              mon program is invoked with the -D option.

       inet_interfaces (all)
              The network interface addresses that this mail sys-
              tem receives mail on.

       inet_protocols (all)
              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  direc-
              tory.

       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 val-
       ues, 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(8)