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 mmaasstteerr(8) process. The master.cf configuration file defines how a client program connects to a service, and what daemon program runs when a service is requested. Most daemon processes are short-lived and terminate voluntarily after serving mmaaxx__uussee clients, or after inactivity for mmaaxx__iiddllee or more units of time.

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

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

SYNTAX



The general format of the master.cf file is as follows:
· Each logical line defines a single Postfix service.
Each service 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.
· Empty lines and whitespace-only lines are ignored, as are
lines whose first non-whitespace character is a `#'.
· 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.

SSeerrvviiccee nnaammee The service name syntax depends on the service type as
described next.
SSeerrvviiccee ttyyppee Specify one of the following service types:
iinneett The service listens on a TCP/IP socket and is accessible
via the network.

The service name is specified as _h_o_s_t_:_p_o_r_t, 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 112277..00..00..11::ssmmttpp or ::::11::ssmmttpp receives mail via the loopback interface only; and a service named 1100002255 accepts connections on TCP port 10025 via all interfaces configured with the iinneett__iinntteerrffaacceess parameter.



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

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

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

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

ffiiffoo The service listens on a FIFO (named pipe) and is accessible
for local clients only.

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

ppaassss 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 qquueeuuee__ddiirreeccttoorryy configuration parameter in main.cf).

This feature is available as of Postfix version 2.5.

PPrriivvaattee ((ddeeffaauulltt:: yy)) Whether or not access is restricted to the mail system.
Internet (type iinneett) services can't be private.
UUnnpprriivviilleeggeedd ((ddeeffaauulltt:: yy)) Whether the service runs with root privileges or as the
owner of the Postfix system (the owner name is controlled by the mmaaiill__oowwnneerr configuration variable in the main.cf file).

The llooccaall(8), ppiippee(8), ssppaawwnn(8), and vviirrttuuaall(8) daemons require privileges.
CChhrroooott ((ddeeffaauulltt:: yy)) Whether or not the service runs chrooted to the mail queue
directory (pathname is controlled by the qquueeuuee__ddiirreeccttoorryy configuration variable in the main.cf file).

Chroot should not be used with the llooccaall(8), ppiippee(8), ssppaawwnn(8), and vviirrttuuaall(8) daemons. Although the pprrooxxyymmaapp(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 Postfix 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.
WWaakkee uupp ttiimmee ((ddeeffaauulltt:: 00)) Automatically wake up the named service after the specified
number 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 automatic wake up.

The ppiicckkuupp(8), qqmmggrr(8) and fflluusshh(8) daemons require a wake up timer.
PPrroocceessss lliimmiitt ((ddeeffaauulltt:: $$ddeeffaauulltt__pprroocceessss__lliimmiitt)) 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, qqmmggrr(8)) and some services must be configured with no process limit (for example, cclleeaannuupp(8)). These limits must not be changed.
CCoommmmaanndd nnaammee ++ aarrgguummeennttss 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 whitespace.

The command name is relative to the Postfix daemon directory (pathname is controlled by the ddaaeemmoonn__ddiirreeccttoorryy 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:
--DD Run the daemon under control by the command specified with
the ddeebbuuggggeerr__ccoommmmaanndd variable in the main.cf configuration file. See DEBUG_README for hints and tips.
--oo _n_a_m_e=_v_a_l_u_e Override the named main.cf configuration parameter. The
parameter value can refer to other parameters as _$_n_a_m_e etc., just like in main.cf. See ppoossttccoonnff(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 multiple instances of Postfix, instead of configuring multiple personalities via master.cf.
--vv Increase the verbose logging level. Specify multiple --vv
options to make a Postfix daemon process increasingly verbose.

SEE ALSO


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

README FILES



Use "ppoossttccoonnff rreeaaddmmee__ddiirreeccttoorryy" or
"ppoossttccoonnff hhttmmll__ddiirreeccttoorryy" 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