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 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 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 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. | ||||||||
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:
| ||||||||
Private (default: y) | Whether or not access is restricted to the mail system. Internet (type inet) services cant 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
configuration 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 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. | ||||||||
Wake up time (default: 0) |
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 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 whitespace.
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:
| ||||||||
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