    MASTER(8)                                                            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 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.

           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).

    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 the next  service  request
                  before exiting.

           max_use (100)
                  The  maximal number of connection requests before a
                  Postfix daemon process terminates.

           service_throttle_time (60s)
                  How long the Postfix master(8) waits before forking
                  a server that appears to be malfunctioning.

    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 (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 direc-
                  tory.

           syslog_facility (mail)
                  The syslog facility of Postfix logging.

           syslog_name (postfix)
                  The mail system  name  that  is  prepended  to  the
                  process  name  in  syslog  records, so that "smtpd"
                  becomes, for example, "postfix/smtpd".

    FILES
           /etc/postfix/main.cf, global configuration file.
           /etc/postfix/master.cf, master server configuration file.
           /var/spool/postfix/pid/master.pid, 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)