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 controlling 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 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
              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). 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 processes 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
              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 connections.

       import_environment (see 'postconf -d' output)
              The  list  of  environment  parameters  that  a  privileged  Postfix  process  will  import from a
              non-Postfix parent process, or name=value environment overrides.

       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)
              A prefix that is prepended to the process name in syslog records, so that,  for  example,  "smtpd"
              becomes "prefix/smtpd".

       Available in Postfix 3.3 and later:

       service_name (read-only)
              The master.cf service name of a Postfix daemon process.

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

       Wietse Venema
       Google, Inc.
       111 8th Avenue
       New York, NY 10011, USA

                                                                                                MASTER(8postfix)