MASTER(8)                                               MASTER(8)

NAME
       master - Postfix master process

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

DESCRIPTION
       The  master daemon is the resident process that runs Post-
       fix 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. The exception
       to this rule is the resident Postfix queue manager.

       The behavior of the master daemon  is  controlled  by  the
       master.cf  configuration file. The table specifies zero or
       more servers in the UNIX or INET domain, or  servers  that
       take  requests  from a FIFO. Precise configuration details
       are given in the master.cf file, and in the  manual  pages
       of the respective daemons.

       Options:

       -c config_dir
              Read  the main.cf and master.cf configuration files
              in the named directory instead of the default  con-
              figuration directory.

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

       -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.

       -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
              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 configura-
              tion  files. If a service has been removed from the
              master.cf file, its running  processes  are  termi-
              nated  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).

BUGS
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
       The  following  main.cf parameters are especially relevant
       to this program. See the Postfix main.cf file  for  syntax
       details  and  for  default  values. Use the postfix reload
       command after a configuration change.

Miscellaneous
       import_environment

       export_environment
              Lists of names of environment parameters  that  can
              be  imported  from  (exported  to) non-Postfix pro-
              cesses.

       mail_owner
              The owner of the mail queue  and  of  most  Postfix
              processes.

       command_directory
              Directory with Postfix support programs.

       daemon_directory
              Directory with Postfix daemon programs.

       queue_directory
              Top-level  directory  of the Postfix queue. This is
              also the root directory of Postfix daemons that run
              chrooted.

       inet_interfaces
              The  network  interface  addresses that this system
              receives mail on.  You need to stop and start Post-
              fix when this parameter changes.

Resource controls
       default_process_limit
              Default  limit for the number of simultaneous child
              processes that provide a given service.

       max_idle
              Limit the time in  seconds  that  a  child  process
              waits between service requests.

       max_use
              Limit  the  number of service requests handled by a
              child process.

       service_throttle_time
              Time to avoid forking a server that appears  to  be
              broken.

FILES
       /etc/postfix/main.cf: global configuration file.
       /etc/postfix/master.cf: master process configuration file.
       /var/spool/postfix/pid/master.pid: master lock file.

SEE ALSO
       qmgr(8) queue manager
       pickup(8) local mail pickup
       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)