.TH MASTER 8 
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.SH NAME
master
\-
Postfix master process
.SH SYNOPSIS
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\fBmaster\fR [\fB-Dtv\fR] [\fB-c \fIconfig_dir\fR]
[\fB-e \fIexit_time\fR]
.SH DESCRIPTION
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The \fBmaster\fR daemon is the resident process that runs Postfix
daemons on demand: daemons to send or receive messages via the
network, daemons to deliver mail locally, etc.  These daemons are
created on demand up to a configurable maximum number per service.

Postfix daemons terminate voluntarily, either after being idle for
a configurable amount of time, or after having serviced a
configurable number of requests. The exception to this rule is the
resident Postfix queue manager.

The behavior of the \fBmaster\fR daemon is controlled by the
\fBmaster.cf\fR configuration file. The table specifies zero or
more servers in the \fBUNIX\fR or \fBINET\fR domain, or servers
that take requests from a FIFO. Precise configuration details are
given in the \fBmaster.cf\fR file, and in the manual pages of the
respective daemons.

Options:
.IP "\fB-c \fIconfig_dir\fR"
Read the \fBmain.cf\fR and \fBmaster.cf\fR configuration files in
the named directory instead of the default configuration directory.
.IP "\fB-e \fIexit_time\fR"
Terminate the master process after \fIexit_time\fR seconds. Child
processes terminate at their convenience.
.IP \fB-D\fR
After initialization, run a debugger on the master process. The
debugging command is specified with the \fBdebugger_command\fR in
the \fBmain.cf\fR global configuration file.
.IP \fB-t\fR
Test mode. Return a zero exit status when the \fBmaster.pid\fR lock
file does not exist or when that file is not locked.  This is evidence
that the \fBmaster\fR daemon is not running.
.IP \fB-v\fR
Enable verbose logging for debugging purposes. This option
is passed on to child processes. Multiple \fB-v\fR options
make the software increasingly verbose.
.PP
Signals:
.IP \fBSIGHUP\fR
Upon receipt of a \fBHUP\fR signal (e.g., after \fBpostfix reload\fR),
the master process re-reads its configuration files. If a service has
been removed from the \fBmaster.cf\fR file, its running processes
are terminated immediately.
Otherwise, running processes are allowed to terminate as soon
as is convenient, so that changes in configuration settings
affect only new service requests.
.IP \fBSIGTERM\fR
Upon receipt of a \fBTERM\fR signal (e.g., after \fBpostfix abort\fR),
the master process passes the signal on to its child processes and
terminates.
This is useful for an emergency shutdown. Normally one would
terminate only the master (\fBpostfix stop\fR) and allow running
processes to finish what they are doing.
.SH DIAGNOSTICS
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Problems are reported to \fBsyslogd\fR(8).
.SH BUGS
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.SH ENVIRONMENT
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.IP \fBMAIL_DEBUG\fR
After initialization, start a debugger as specified with the
\fBdebugger_command\fR configuration parameter in the \fBmain.cf\fR
configuration file.
.IP \fBMAIL_CONFIG\fR
Directory with Postfix configuration files.
.SH CONFIGURATION PARAMETERS
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The following \fBmain.cf\fR parameters are especially relevant to
this program. See the Postfix \fBmain.cf\fR file for syntax details
and for default values. Use the \fBpostfix reload\fR command after
a configuration change.
.SH Miscellaneous
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.IP \fBimport_environment\fR
.IP \fBexport_environment\fR
Lists of names of environment parameters that can be imported
from (exported to) non-Postfix processes.
.IP \fBmail_owner\fR
The owner of the mail queue and of most Postfix processes.
.IP \fBcommand_directory\fR
Directory with Postfix support programs.
.IP \fBdaemon_directory\fR
Directory with Postfix daemon programs.
.IP \fBqueue_directory\fR
Top-level directory of the Postfix queue. This is also the root
directory of Postfix daemons that run chrooted.
.IP \fBinet_interfaces\fR
The network interface addresses that this system receives mail on.
You need to stop and start Postfix when this parameter changes.
.SH "Resource controls"
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.IP \fBdefault_process_limit\fR
Default limit for the number of simultaneous child processes that
provide a given service.
.IP \fBmax_idle\fR
Limit the time in seconds that a child process waits between
service requests.
.IP \fBmax_use\fR
Limit the number of service requests handled by a child process.
.IP \fBservice_throttle_time\fR
Time to avoid forking a server that appears to be broken.
.SH FILES
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/etc/postfix/main.cf: global configuration file.
/etc/postfix/master.cf: master process configuration file.
/var/spool/postfix/pid/master.pid: master lock file.
.SH SEE ALSO
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qmgr(8) queue manager
pickup(8) local mail pickup
syslogd(8) system logging
.SH LICENSE
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The Secure Mailer license must be distributed with this software.
.SH AUTHOR(S)
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Wietse Venema
IBM T.J. Watson Research
P.O. Box 704
Yorktown Heights, NY 10598, USA