Ubuntu Manpage: master - Postfix master process

Provided by: postfix_3.10.2-1ubuntu2_amd64

NAME

       master - Postfix master process

SYNOPSIS

       master [-Dditvw] [-c config_dir] [-e exit_time]

DESCRIPTION

The master(8) 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
manager, address verification server, and the TLS session cache and pseudo-random number server.

The behavior of the master(8) daemon is controlled by the master.cf configuration file, as described in
master(5).

Options:

-c config_dir
Read the main.cf and master.cf configuration files in the named directory instead of the default
configuration directory. This also overrides the configuration files for other Postfix daemon
processes.

-D After initialization, run a debugger on the master process. The debugging command is specified
with the debugger_command in the main.cf global configuration file.

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

-e exit_time
Terminate the master process after exit_time seconds. Child processes terminate at their
convenience.

-i Enable init mode: do not become a session or process group leader; and similar to -s, do not
redirect stdout to /dev/null, so that "maillog_file = /dev/stdout" works. This mode is allowed
only if the process ID equals 1.

This feature is available in Postfix 3.3 and later.

-s Do not redirect stdout to /dev/null, so that "maillog_file = /dev/stdout" works.

This feature is available in Postfix 3.4 and later.

-t Test mode. Return a zero exit status when the master.pid lock file does not exist or when that
file is not locked. This is evidence that the master(8) daemon is not running.

-v Enable verbose logging for debugging purposes. This option is passed on to child processes.
Multiple -v options make the software increasingly verbose.

-w 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 reasonable amount of time.

This feature is available in Postfix 2.10 and later.

Signals:

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

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

DIAGNOSTICS

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

ENVIRONMENT

       MAIL_DEBUG
              After  initialization,  start  a  debugger  as  specified  with the debugger_command configuration
              parameter in the main.cf configuration file.

       MAIL_CONFIG
              Directory with Postfix configuration files.

CONFIGURATION PARAMETERS

       Unlike most Postfix daemon processes, the master(8) server does not  automatically  pick  up  changes  to
       main.cf.  Changes to master.cf are never picked up automatically.  Use the "postfix reload" command after
       a configuration change.

RESOURCE AND RATE CONTROLS

       default_process_limit (100)
              The default maximal number of Postfix child processes that provide a given service.

       max_idle (100s)
              The maximum amount of time that an idle Postfix daemon process waits for  an  incoming  connection
              before terminating voluntarily.

       max_use (100)
              The  maximal  number  of  incoming  connections  that a Postfix daemon process will service before
              terminating voluntarily.

       service_throttle_time (60s)
              How long the Postfix master(8) waits before forking a server that appears to be malfunctioning.

       Available in Postfix version 2.6 and later:

       master_service_disable (empty)
              Selectively disable master(8) listener ports by service type or by service name and type.

MISCELLANEOUS CONTROLS

       config_directory (see 'postconf -d' output)
              The default location of the Postfix main.cf and master.cf configuration files.

       daemon_directory (see 'postconf -d' output)
              The directory with Postfix support programs and daemon programs.

       debugger_command (empty)
              The external command to execute when a Postfix daemon program is invoked with the -D option.

       inet_interfaces (all)
              The local network interface addresses that this mail system receives mail on.

       inet_protocols (see 'postconf -d' output)
              The Internet protocols Postfix will attempt to use when making or accepting connections.

       import_environment (see 'postconf -d' output)
              The list of environment variables that a privileged Postfix process will import from a non-Postfix
              parent process, or name=value environment overrides.

       mail_owner (postfix)
              The UNIX system account that owns the Postfix queue and most Postfix daemon processes.

       process_id (read-only)
              The process ID of a Postfix command or daemon process.

       process_name (read-only)
              The process name of a Postfix command or daemon process.

       queue_directory (see 'postconf -d' output)
              The location of the Postfix top-level queue directory.

       syslog_facility (mail)
              The syslog facility of Postfix logging.

       syslog_name (see 'postconf -d' output)
              A prefix that is prepended to the process name in syslog records, so that,  for  example,  "smtpd"
              becomes "prefix/smtpd".

       Available in Postfix 3.3 and later:

       service_name (read-only)
              The master.cf service name of a Postfix daemon process.

       Available in Postfix 3.6 and later:

       known_tcp_ports (lmtp=24, smtp=25, smtps=submissions=465, submission=587)
              Optional setting that avoids lookups in the services(5) database.

FILES

       To expand the directory names below into their actual values, use the command "postconf config_directory"
       etc.

       $config_directory/main.cf, global configuration file.
       $config_directory/master.cf, master server configuration file.
       $queue_directory/pid/master.pid, master lock file.
       $data_directory/master.lock, master lock file.

LICENSE

       The Secure Mailer license must be distributed with this software.

AUTHOR(S)

       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)