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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      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.

       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.

       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 ac-
		     cepted. The host part (and	colon) may be omitted.	Either
		     host  or port may be given	in symbolic form (see hosts(5)
		     or	services(5)) or	in numeric form	(IP  address  or  port
		     number).	Host  information may be enclosed inside "[]";
		     this form is necessary only with IPv6 addresses.

		     Examples: a service named 127.0.0.1:smtp or ::1:smtp  re-
		     ceives  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 stream socket	and is
		     accessible	for local clients only.

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

		     On	Solaris	8 and earlier systems the unix type is	imple-
		     mented with streams sockets.

	      unix-dgram
		     The  service listens on a UNIX-domain datagram socket and
		     is	accessible for local clients only.

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

	      fifo (obsolete)
		     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_di-
		     rectory configuration parameter in	main.cf).

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

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

		     On	Solaris	8 and earlier systems the pass type is	imple-
		     mented with streams sockets.

		     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:	Postfix	>= 3.0:	n, Postfix <3.0: y)
	      Whether  or  not the service runs	chrooted to the	mail queue di-
	      rectory (pathname	is controlled by the queue_directory  configu-
	      ration 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 show how to set up a Postfix chroot environment on a
	      variety of systems. See also BASIC_CONFIGURATION_README for  is-
	      sues 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  be-
	      fore  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  sin-
	      gle-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. To	protect	whitespace, use	"{" and	"}" as	described  be-
	      low.

	      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	} (long	form, Postfix >= 3.0)

	      -o name=value (short form)
		     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: With the "long form" shown above,	whitespace af-
		     ter "{", around "=",  and	before	"}"  is	 ignored,  and
		     whitespace	within the parameter value is preserved.

		     NOTE 2: with the "short form" shown above,	do not specify
		     whitespace	around the "="	or  in	parameter  values.  To
		     specify  a	 parameter value that contains whitespace, use
		     the long form described above, or use commas  instead  of
		     spaces, or	specify	the value in main.cf. Example:

		     /usr/local/etc/postfix/master.cf:
			 submission inet .... smtpd
			     -o	smtpd_xxx_yyy=$submission_xxx_yyy

		     /usr/local/etc/postfix/main.cf
			 submission_xxx_yyy = text with	whitespace...

		     NOTE 3: 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.

	      Other command-line arguments
		     Specify "{" and "}" around	command	arguments that contain
		     whitespace	(Postfix 3.0 and later). Whitespace after  "{"
		     and before	"}" is ignored.

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

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

								     MASTER(5)

NAME | DESCRIPTION | SYNTAX | SEE ALSO | README FILES | LICENSE | AUTHOR(S)

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