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MASTER(8)                                                            MASTER(8)

<b>NAME</b>
       master - Postfix master process

<b>SYNOPSIS</b>
       <b>master</b> [<b>-Ddtvw</b>] [<b>-c</b> <i>config</i><b>_</b><i>dir</i>] [<b>-e</b> <i>exit</i><b>_</b><i>time</i>]

<b>DESCRIPTION</b>
       The  <a href="master.8.html"><b>master</b>(8)</a> 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. Exceptions to this rule are the resident queue man-
       ager,  address  verification  server,  and  the  TLS  session cache and
       pseudo-random number server.

       The behavior of the <a href="master.8.html"><b>master</b>(8)</a> daemon is  controlled  by  the  <a href="master.5.html"><b>master.cf</b></a>
       configuration file, as described in <a href="master.5.html"><b>master</b>(5)</a>.

       Options:

       <b>-c</b> <i>config</i><b>_</b><i>dir</i>
              Read  the <a href="postconf.5.html"><b>main.cf</b></a> and <a href="master.5.html"><b>master.cf</b></a> configuration files in the named
              directory instead of the default configuration directory.   This
              also  overrides the configuration files for other Postfix daemon
              processes.

       <b>-D</b>     After initialization, run a debugger on the master process.  The
              debugging  command is specified with the <b><a href="postconf.5.html#debugger_command">debugger_command</a></b> in the
              <a href="postconf.5.html"><b>main.cf</b></a> global configuration file.

       <b>-d</b>     Do not redirect stdin, stdout or stderr to /dev/null, and do not
              discard  the  controlling terminal. This must be used for debug-
              ging only.

       <b>-e</b> <i>exit</i><b>_</b><i>time</i>
              Terminate the master process after <i>exit</i><b>_</b><i>time</i> seconds. Child pro-
              cesses terminate at their convenience.

       <b>-t</b>     Test  mode.  Return  a zero exit status when the <b>master.pid</b> lock
              file does not exist or when that file is not  locked.   This  is
              evidence that the <a href="master.8.html"><b>master</b>(8)</a> daemon is not running.

       <b>-v</b>     Enable  verbose  logging  for debugging purposes. This option is
              passed on to child processes. Multiple <b>-v</b> options make the soft-
              ware increasingly verbose.

       <b>-w</b>     Wait in a dummy foreground process, while the real master daemon
              initializes in  a  background  process.   The  dummy  foreground
              process  returns  a  zero  exit status only if the master daemon
              initialization is successful, and if it completes in  a  reason-
              able amount of time.

              This feature is available in Postfix 2.10 and later.

       Signals:

       <b>SIGHUP</b> Upon receipt of a <b>HUP</b> signal (e.g., after "<b>postfix reload</b>"), the
              master process re-reads its configuration files.  If  a  service
              has  been removed from the <a href="master.5.html"><b>master.cf</b></a> 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.

       <b>SIGTERM</b>
              Upon receipt of a <b>TERM</b> signal (e.g., after "<b>postfix abort</b>"), 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 ("<b>postfix stop</b>") and allow
              running processes to finish what they are doing.

<b>DIAGNOSTICS</b>
       Problems are reported to <b>syslogd</b>(8). The exit  status  is  non-zero  in
       case  of  problems,  including  problems while initializing as a master
       daemon process in the background.

<b>ENVIRONMENT</b>
       <b>MAIL_DEBUG</b>
              After initialization, start a debugger  as  specified  with  the
              <b><a href="postconf.5.html#debugger_command">debugger_command</a></b> configuration parameter in the <a href="postconf.5.html"><b>main.cf</b></a> configu-
              ration file.

       <b>MAIL_CONFIG</b>
              Directory with Postfix configuration files.

<b>CONFIGURATION PARAMETERS</b>
       Unlike most Postfix daemon processes, the  <a href="master.8.html"><b>master</b>(8)</a>  server  does  not
       automatically  pick  up  changes  to  <a href="postconf.5.html"><b>main.cf</b></a>. Changes to <a href="master.5.html"><b>master.cf</b></a> are
       never picked up automatically.  Use the "<b>postfix reload</b>" command  after
       a configuration change.

<b>RESOURCE AND RATE CONTROLS</b>
       <b><a href="postconf.5.html#default_process_limit">default_process_limit</a> (100)</b>
              The  default maximal number of Postfix child processes that pro-
              vide a given service.

       <b><a href="postconf.5.html#max_idle">max_idle</a> (100s)</b>
              The maximum amount of time that an idle Postfix  daemon  process
              waits for an incoming connection before terminating voluntarily.

       <b><a href="postconf.5.html#max_use">max_use</a> (100)</b>
              The maximal number of incoming connections that a Postfix daemon
              process will service before terminating voluntarily.

       <b><a href="postconf.5.html#service_throttle_time">service_throttle_time</a> (60s)</b>
              How  long  the  Postfix  <a href="master.8.html"><b>master</b>(8)</a> waits before forking a server
              that appears to be malfunctioning.

       Available in Postfix version 2.6 and later:

       <b><a href="postconf.5.html#master_service_disable">master_service_disable</a> (empty)</b>
              Selectively disable <a href="master.8.html"><b>master</b>(8)</a> listener ports by service type  or
              by service name and type.

<b>MISCELLANEOUS CONTROLS</b>
       <b><a href="postconf.5.html#config_directory">config_directory</a> (see 'postconf -d' output)</b>
              The  default  location of the Postfix <a href="postconf.5.html">main.cf</a> and <a href="master.5.html">master.cf</a> con-
              figuration files.

       <b><a href="postconf.5.html#daemon_directory">daemon_directory</a> (see 'postconf -d' output)</b>
              The directory with Postfix support programs and daemon programs.

       <b><a href="postconf.5.html#debugger_command">debugger_command</a> (empty)</b>
              The external command to execute when a Postfix daemon program is
              invoked with the -D option.

       <b><a href="postconf.5.html#inet_interfaces">inet_interfaces</a> (all)</b>
              The network interface addresses that this mail  system  receives
              mail on.

       <b><a href="postconf.5.html#inet_protocols">inet_protocols</a> (all)</b>
              The  Internet  protocols Postfix will attempt to use when making
              or accepting connections.

       <b><a href="postconf.5.html#import_environment">import_environment</a> (see 'postconf -d' output)</b>
              The list of environment parameters that a Postfix  process  will
              import from a non-Postfix parent process.

       <b><a href="postconf.5.html#mail_owner">mail_owner</a> (postfix)</b>
              The  UNIX  system  account  that owns the Postfix queue and most
              Postfix daemon processes.

       <b><a href="postconf.5.html#process_id">process_id</a> (read-only)</b>
              The process ID of a Postfix command or daemon process.

       <b><a href="postconf.5.html#process_name">process_name</a> (read-only)</b>
              The process name of a Postfix command or daemon process.

       <b><a href="postconf.5.html#queue_directory">queue_directory</a> (see 'postconf -d' output)</b>
              The location of the Postfix top-level queue directory.

       <b><a href="postconf.5.html#syslog_facility">syslog_facility</a> (mail)</b>
              The syslog facility of Postfix logging.

       <b><a href="postconf.5.html#syslog_name">syslog_name</a> (see 'postconf -d' output)</b>
              The mail system name that is prepended to the  process  name  in
              syslog  records,  so  that  "smtpd" becomes, for example, "post-
              fix/smtpd".

<b>FILES</b>
       To expand the directory names below into their actual values,  use  the
       command "<b>postconf <a href="postconf.5.html#config_directory">config_directory</a></b>" etc.

       $<a href="postconf.5.html#config_directory">config_directory</a>/<a href="postconf.5.html">main.cf</a>, global configuration file.
       $<a href="postconf.5.html#config_directory">config_directory</a>/<a href="master.5.html">master.cf</a>, master server configuration file.
       $<a href="postconf.5.html#queue_directory">queue_directory</a>/pid/master.pid, master lock file.
       $<a href="postconf.5.html#data_directory">data_directory</a>/master.lock, master lock file.

<b>SEE ALSO</b>
       <a href="qmgr.8.html">qmgr(8)</a>, queue manager
       <a href="verify.8.html">verify(8)</a>, address verification
       <a href="master.5.html">master(5)</a>, <a href="master.5.html">master.cf</a> configuration file syntax
       <a href="postconf.5.html">postconf(5)</a>, <a href="postconf.5.html">main.cf</a> configuration file syntax
       syslogd(8), system logging

<b>LICENSE</b>
       The Secure Mailer license must be distributed with this software.

<b>AUTHOR(S)</b>
       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(8)
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