<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> <title> Postfix manual - master(5) </title> </head> <body> <pre> MASTER(5) MASTER(5) <b>NAME</b> master - Postfix master process configuration file format <b>DESCRIPTION</b> 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 <a href="master.8.html"><b>master</b>(8)</a> process. The <a href="master.5.html">master.cf</a> configuration file defines how a client program connects to a service, and what daemon pro- gram runs when a service is requested. Most daemon pro- cesses are short-lived and terminate voluntarily after serving <b><a href="postconf.5.html#max_use">max_use</a></b> clients, or after inactivity for <b><a href="postconf.5.html#max_idle">max_idle</a></b> or more units of time. All daemons specified here must speak a Postfix-internal protocol. In order to execute non-Postfix software use the <a href="local.8.html"><b>local</b>(8)</a>, <a href="pipe.8.html"><b>pipe</b>(8)</a> or <a href="spawn.8.html"><b>spawn</b>(8)</a> services, or run the server under control by <b>inetd</b>(8) or equivalent. After changing <a href="master.5.html">master.cf</a> you must execute "<b>postfix reload</b>" to reload the configuration. <b>SYNTAX</b> The general format of the <a href="master.5.html">master.cf</a> file is as follows: <b>o</b> 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 <a href="master.5.html">master.cf</a> ser- vice definitions does not matter. <b>o</b> Empty lines and whitespace-only lines are ignored, as are lines whose first non-whitespace character is a `#'. <b>o</b> A logical line starts with non-whitespace text. A line that starts with whitespace continues a logi- cal line. Each logical line consists of eight fields separated by whitespace. These are described below in the order as they appear in the <a href="master.5.html">master.cf</a> 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. <b>Service name</b> The service name syntax depends on the service type as described next. <b>Service type</b> Specify one of the following service types: <b>inet</b> The service listens on a TCP/IP socket and is accessible via the network. The service name is specified as <i>host:port</i>, denoting the host and port on which new con- nections 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 <b>127.0.0.1:smtp</b> or <b>::1:smtp</b> receives mail via the loopback interface only; and a service named <b>10025</b> accepts connections on TCP port 10025 via all interfaces configured with the <b><a href="postconf.5.html#inet_interfaces">inet_interfaces</a></b> parameter. Note: with Postfix version 2.2 and later specify "<b><a href="postconf.5.html#inet_interfaces">inet_interfaces</a> = loopback-only</b>" in <a href="postconf.5.html">main.cf</a>, instead of hard-coding loopback IP address information in <a href="master.5.html">master.cf</a> or in <a href="postconf.5.html">main.cf</a>. <b>unix</b> 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 con- trolled with the <b><a href="postconf.5.html#queue_directory">queue_directory</a></b> configura- tion parameter in <a href="postconf.5.html">main.cf</a>). On Solaris systems the <b>unix</b> type is imple- mented with streams sockets. <b>fifo</b> 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 con- trolled with the <b><a href="postconf.5.html#queue_directory">queue_directory</a></b> configura- tion parameter in <a href="postconf.5.html">main.cf</a>). <b>pass</b> The service listens on a UNIX-domain socket, and is accessible to local clients only. It receives one open connection (file descrip- tor passing) per connection request. The service name is a pathname relative to the Postfix queue directory (pathname con- trolled with the <b><a href="postconf.5.html#queue_directory">queue_directory</a></b> configura- tion parameter in <a href="postconf.5.html">main.cf</a>). On Solaris systems the <b>pass</b> type is imple- mented with streams sockets. This feature is available as of Postfix ver- sion 2.5. <b>Private (default: y)</b> Whether or not access is restricted to the mail system. Internet (type <b>inet</b>) services can't be private. <b>Unprivileged (default: y)</b> Whether the service runs with root privileges or as the owner of the Postfix system (the owner name is controlled by the <b><a href="postconf.5.html#mail_owner">mail_owner</a></b> configuration variable in the <a href="postconf.5.html">main.cf</a> file). The <a href="local.8.html"><b>local</b>(8)</a>, <a href="pipe.8.html"><b>pipe</b>(8)</a>, <a href="spawn.8.html"><b>spawn</b>(8)</a>, and <a href="virtual.8.html"><b>virtual</b>(8)</a> daemons require privileges. <b>Chroot (default: y)</b> Whether or not the service runs chrooted to the mail queue directory (pathname is controlled by the <b><a href="postconf.5.html#queue_directory">queue_directory</a></b> configuration variable in the <a href="postconf.5.html">main.cf</a> file). Chroot should not be used with the <a href="local.8.html"><b>local</b>(8)</a>, <a href="pipe.8.html"><b>pipe</b>(8)</a>, <a href="spawn.8.html"><b>spawn</b>(8)</a>, and <a href="virtual.8.html"><b>virtual</b>(8)</a> daemons. Although the <a href="proxymap.8.html"><b>proxymap</b>(8)</a> 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 <a href="BASIC_CONFIGURATION_README.html">BASIC_CONFIGURATION_README</a> for issues related to running daemons chrooted. <b>Wake up time (default: 0)</b> Automatically wake up the named service after the specified number of seconds. The wake up is imple- mented 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 <a href="pickup.8.html"><b>pickup</b>(8)</a>, <a href="qmgr.8.html"><b>qmgr</b>(8)</a> and <a href="flush.8.html"><b>flush</b>(8)</a> daemons require a wake up timer. <b>Process limit (default: $<a href="postconf.5.html#default_process_limit">default_process_limit</a>)</b> The maximum number of processes that may execute this service simultaneously. Specify 0 for no process count limit. NOTE: Some Postfix services must be configured as a single-process service (for example, <a href="qmgr.8.html"><b>qmgr</b>(8)</a>) and some services must be configured with no process limit (for example, <a href="cleanup.8.html"><b>cleanup</b>(8)</a>). These limits must not be changed. <b>Command name + arguments</b> The command to be executed. Characters that are special to the shell such as ">" or "|" have no special meaning here, and quotes cannot be used to protect arguments containing whitespace. The command name is relative to the Postfix daemon directory (pathname is controlled by the <b><a href="postconf.5.html#daemon_directory">dae</a>-</b> <b><a href="postconf.5.html#daemon_directory">mon_directory</a></b> configuration variable). The command argument syntax for specific commands is specified in the respective daemon manual page. The following command-line options have the same effect for all daemon programs: <b>-D</b> Run the daemon under control by the command specified with the <b><a href="postconf.5.html#debugger_command">debugger_command</a></b> variable in the <a href="postconf.5.html">main.cf</a> configuration file. See <a href="DEBUG_README.html">DEBUG_README</a> for hints and tips. <b>-o</b> <i>name</i>=<i>value</i> Override the named <a href="postconf.5.html">main.cf</a> configuration parameter. The parameter value can refer to other parameters as <i>$name</i> etc., just like in <a href="postconf.5.html">main.cf</a>. See <a href="postconf.5.html"><b>postconf</b>(5)</a> 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 $over- ride_parameter set in <a href="postconf.5.html">main.cf</a>. NOTE 2: Over-zealous use of parameter over- rides 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 con- figuring multiple personalities via mas- ter.cf. <b>-v</b> Increase the verbose logging level. Specify multiple <b>-v</b> options to make a Postfix daemon process increasingly verbose. <b>SEE ALSO</b> <a href="master.8.html">master(8)</a>, process manager <a href="postconf.5.html">postconf(5)</a>, configuration parameters <b>README FILES</b> <a href="BASIC_CONFIGURATION_README.html">BASIC_CONFIGURATION_README</a>, basic configuration <a href="DEBUG_README.html">DEBUG_README</a>, Postfix debugging <b>LICENSE</b> The Secure Mailer license must be distributed with this software. <b>AUTHOR(S)</b> 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) </pre> </body> </html>