MASTER(5)		      File Formats Manual		     MASTER(5)



NAME
       master - Postfix master process configuration file format

DESCRIPTION
       The  Postfix  mail  system  is  implemented by small number of (mostly)
       client commands that are invoked by users, and by a  larger  number  of
       services that run in the background.

       Postfix	services are implemented by daemon processes. These run in the
       background under control of the master(8) process.  The master.cf  con-
       figuration file defines how a client program connects to a service, and
       what daemon program runs when a service is requested.  Most daemon pro-
       cesses  are short-lived and terminate voluntarily after serving max_use
       clients, or after inactivity for max_idle or more units of time.

       All daemons specified here must speak a Postfix-internal	 protocol.  In
       order  to  execute  non-Postfix	software  use the local(8), pipe(8) or
       spawn(8) services, or run the  server  under  control  by  inetd(8)  or
       equivalent.

       After  changing	master.cf  you must execute "postfix reload" to reload
       the configuration.

SYNTAX
       The general format of the master.cf file is as follows:

       o      Each logical line defines a single Postfix service.   Each  ser-
	      vice  is	identified  by	its  name and type as described below.
	      When multiple lines specify the same service name and type, only
	      the  last	 one is remembered.  Otherwise, the order of master.cf
	      service definitions does not matter.

       o      Empty lines and whitespace-only lines are ignored, as are	 lines
	      whose first non-whitespace character is a `#'.

       o      A	 logical  line	starts	with  non-whitespace text. A line that
	      starts with whitespace continues a logical line.

       Each logical line consists of eight  fields  separated  by  whitespace.
       These  are described below in the order as they appear in the master.cf
       file.

       Where applicable a field of "-"	requests  that	the  built-in  default
       value  be  used.	 For boolean fields specify "y" or "n" to override the
       default value.

       Service name
	      The service name syntax depends on the service type as described
	      next.

       Service type
	      Specify one of the following service types:

	      inet   The  service listens on a TCP/IP socket and is accessible
		     via the network.

		     The service name is specified as host:port, denoting  the
		     host   and	 port  on  which  new  connections  should  be
		     accepted. The host	 part  (and  colon)  may  be  omitted.
		     Either  host  or port may be given in symbolic form (host
		     or service name) or in numeric form (IP address  or  port
		     number).	Host  information may be enclosed inside "[]",
		     but this form is not necessary.

		     Examples: a  service  named  127.0.0.1:smtp  or  ::1:smtp
		     receives mail via the loopback interface only; and a ser-
		     vice named 10025 accepts connections on  TCP  port	 10025
		     via  all  interfaces  configured with the inet_interfaces
		     parameter.


		     Note:  with  Postfix  version  2.2	 and   later   specify
		     "inet_interfaces  = loopback-only" in main.cf, instead of
		     hard-coding loopback IP address information in  master.cf
		     or in main.cf.

	      unix   The service listens on a UNIX-domain socket and is acces-
		     sible for local clients only.

		     The service name is a pathname relative  to  the  Postfix
		     queue    directory	   (pathname   controlled   with   the
		     queue_directory configuration parameter in main.cf).

		     On Solaris systems the  unix  type	 is  implemented  with
		     streams sockets.

	      fifo   The  service listens on a FIFO (named pipe) and is acces-
		     sible for local clients only.

		     The service name is a pathname relative  to  the  Postfix
		     queue    directory	   (pathname   controlled   with   the
		     queue_directory configuration parameter in main.cf).

	      pass   The service listens on a UNIX-domain socket, receives one
		     open  connection (file descriptor passing) per connection
		     request, and is accessible to local clients only.

		     The service name is a pathname relative  to  the  Postfix
		     queue    directory	   (pathname   controlled   with   the
		     queue_directory configuration parameter in main.cf).

		     This feature is available as of Postfix version 2.5.

       Private (default: y)
	      Whether or not access is restricted to the mail system.	Inter-
	      net (type inet) services can't be private.

       Unprivileged (default: y)
	      Whether the service runs with root privileges or as the owner of
	      the  Postfix  system  (the  owner	 name  is  controlled  by  the
	      mail_owner configuration variable in the main.cf file).

	      The  local(8), pipe(8), spawn(8), and virtual(8) daemons require
	      privileges.

       Chroot (default: y)
	      Whether or not the service  runs	chrooted  to  the  mail	 queue
	      directory (pathname is controlled by the queue_directory config-
	      uration variable in the main.cf file).

	      Chroot should not be used with the local(8), pipe(8),  spawn(8),
	      and virtual(8) daemons.  Although the proxymap(8) server can run
	      chrooted, doing so defeats most of the purpose  of  having  that
	      service in the first place.

	      The files in the examples/chroot-setup subdirectory of the Post-
	      fix source archive show set up a Postfix chroot environment on a
	      variety  of  systems.  See  also	BASIC_CONFIGURATION_README for
	      issues related to running daemons chrooted.

       Wake up time (default: 0)
	      Automatically wake up the named service after the specified num-
	      ber  of seconds. The wake up is implemented by connecting to the
	      service and sending a wake up request.  A ? at the  end  of  the
	      wake-up  time  field  requests  that  no	wake up events be sent
	      before the first time a service is used.	Specify 0 for no auto-
	      matic wake up.

	      The  pickup(8),  qmgr(8)	and flush(8) daemons require a wake up
	      timer.

       Process limit (default: $default_process_limit)
	      The maximum number of processes that may	execute	 this  service
	      simultaneously. Specify 0 for no process count limit.

	      NOTE:  Some  Postfix  services  must  be configured as a single-
	      process service (for example, qmgr(8)) and some services must be
	      configured  with	no  process  limit  (for example, cleanup(8)).
	      These limits must not be changed.

       Command name + arguments
	      The command to be executed.  Characters that are special to  the
	      shell  such  as  ">"  or	"|"  have no special meaning here, and
	      quotes cannot be used to	protect	 arguments  containing	white-
	      space.

	      The  command  name  is  relative to the Postfix daemon directory
	      (pathname is controlled by  the  daemon_directory	 configuration
	      variable).

	      The  command  argument syntax for specific commands is specified
	      in the respective daemon manual page.

	      The following command-line options have the same effect for  all
	      daemon programs:

	      -D     Run  the  daemon  under  control by the command specified
		     with the debugger_command variable in the main.cf config-
		     uration file.  See DEBUG_README for hints and tips.

	      -o name=value
		     Override  the  named main.cf configuration parameter. The
		     parameter value can refer to other	 parameters  as	 $name
		     etc., just like in main.cf.  See postconf(5) for syntax.

		     NOTE  1:  do  not	specify	 whitespace around the "=". In
		     parameter values, either avoid whitespace altogether, use
		     commas  instead of spaces, or consider overrides like "-o
		     name=$override_parameter" with $override_parameter set in
		     main.cf.

		     NOTE 2: Over-zealous use of parameter overrides makes the
		     Postfix configuration hard to  understand	and  maintain.
		     At	 a certain point, it might be easier to configure mul-
		     tiple instances of Postfix, instead of configuring multi-
		     ple personalities via master.cf.

	      -v     Increase  the  verbose logging level. Specify multiple -v
		     options to make a	Postfix	 daemon	 process  increasingly
		     verbose.

SEE ALSO
       master(8), process manager
       postconf(5), configuration parameters

README FILES
       Use  "postconf readme_directory" or "postconf html_directory" to locate
       this information.
       BASIC_CONFIGURATION_README, basic configuration
       DEBUG_README, Postfix debugging

LICENSE
       The Secure Mailer license must be distributed with this software.

AUTHOR(S)
       Initial version by
       Magnus Baeck
       Lund Institute of Technology
       Sweden

       Wietse Venema
       IBM T.J. Watson Research
       P.O. Box 704
       Yorktown Heights, NY 10598, USA



								     MASTER(5)