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MASTER(8postfix) MASTER(8postfix)

NAME

master - Postfix master process

SYNOPSIS

master [-Dditvw] [-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:

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.
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.
Do not redirect stdin, stdout or stderr to /dev/null, and do not discard the controlling terminal. This must be used for debugging only.
Terminate the master process after exit_time seconds. Child processes terminate at their convenience.
Enable init mode: do not become a session or process group leader; and similar to -s, do not redirect stdout to /dev/null, so that "maillog_file = /dev/stdout" works. This mode is allowed only if the process ID equals 1.

This feature is available in Postfix 3.3 and later.

Do not redirect stdout to /dev/null, so that "maillog_file = /dev/stdout" works.

This feature is available in Postfix 3.4 and later.

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.
Enable verbose logging for debugging purposes. This option is passed on to child processes. Multiple -v options make the software increasingly verbose.
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:

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.
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) or postlogd(8). The exit status is non-zero in case of problems, including problems while initializing as a master daemon process in the background.

ENVIRONMENT




  

  
After initialization, start a debugger as specified with the
      debugger_command configuration parameter in the main.cf
      configuration file.

  

  
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





  

  
The default maximal number of Postfix child processes that provide a given
      service.

  

  
The maximum amount of time that an idle Postfix daemon process waits for
      an incoming connection before terminating voluntarily.

  

  
The maximal number of incoming connections that a Postfix daemon process
      will service before terminating voluntarily.

  

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




Available in Postfix version 2.6 and later:



  

  
Selectively disable master(8) listener ports by service type or by
      service name and type.








MISCELLANEOUS CONTROLS





  

  
The default location of the Postfix main.cf and master.cf configuration
      files.

  

  
The directory with Postfix support programs and daemon programs.

  

  
The external command to execute when a Postfix daemon program is invoked
      with the -D option.

  

  
The local network interface addresses that this mail system receives mail
      on.

  

  
The Internet protocols Postfix will attempt to use when making or
      accepting connections.

  

  
The list of environment variables that a privileged Postfix process will
      import from a non-Postfix parent process, or name=value environment
      overrides.

  

  
The UNIX system account that owns the Postfix queue and most Postfix
      daemon processes.

  

  
The process ID of a Postfix command or daemon process.

  

  
The process name of a Postfix command or daemon process.

  

  
The location of the Postfix top-level queue directory.

  

  
The syslog facility of Postfix logging.

  

  
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:



  

  
The master.cf service name of a Postfix daemon process.




Available in Postfix 3.6 and later:



  

  
Optional setting that avoids lookups in the services(5)
    database.








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
postlogd(8), Postfix logging
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