mosquitto.conf(5)														 mosquitto.conf(5)

NAME

       mosquitto.conf - the configuration file for mosquitto

SYNOPSIS

       mosquitto.conf

DESCRIPTION

       mosquitto.conf  is  the	configuration  file  for  mosquitto.  This  file can reside anywhere as long as mosquitto can read it. By default,
       mosquitto does not need a configuration file and will use the default values listed below. See mosquitto(8) for information on how to  load
       a configuration file.

FILE FORMAT

       All lines with a # as the very first character are treated as a comment.

       Configuration lines start with a variable name. The variable value is separated from the name by a single space.

VARIABLES

       acl_file file path
	      Set the path to an access control list file. If defined, the contents of the file are used to control client access to topics on the
	      broker.

	      If this parameter is defined then only the topics listed will have access. Topic access is added with lines of the format:

	      topic [read|write] <topic>

	      The access type is controlled using "read" or "write". This parameter is optional - if not given	then  the  access  is  read/write.
	      <topic> can contain the + or # wildcards as in subscriptions.

	      The first set of topics are applied to anonymous clients, assuming allow_anonymous is true. User specific topic ACLs are added after
	      a user line as follows:

	      user <username>

	      The username referred to here is the same as in password_file. It is not the clientid.

	      It is also possible to define ACLs based on pattern substitution within the topic. The form is the same as for  the  topic  keyword,
	      but using pattern as the keyword.

	      pattern [read|write] <topic>

	      The patterns available for substition are:

	      o %c to match the client id of the client

	      o %u to match the username of the client

	      The  substitution pattern must be the only text for that level of hierarchy. Pattern ACLs apply to all users even if the "user" key-
	      word has previously been given.

	      Example:

	      pattern write sensor/%u/data

	      Reloaded on reload signal. The currently loaded ACLs will be freed and reloaded. Existing subscriptions will be affected	after  the
	      reload.

       allow_anonymous [ true | false ]
	      Boolean value that determines whether clients that connect without providing a username are allowed to connect. If set to false then
	      a password file should be created (see the password_file option) to control authenticated client access. Defaults to true.

	      Reloaded on reload signal.

       autosave_interval seconds
	      The number of seconds that mosquitto will wait between each time it saves the in-memory database to disk. If set to 0, the in-memory
	      database	will only be saved when mosquitto exits or when receiving the SIGUSR1 signal. Note that this setting only has an effect if
	      persistence is enabled. Defaults to 1800 seconds (30 minutes).

	      Reloaded on reload signal.

       bind_address address
	      Listen for incoming network connections on the specified IP address/hostname only. This is useful to restrict access to certain net-
	      work  interfaces. To restrict access to mosquitto to the local host only, use "bind_address localhost". This only applies to the de-
	      fault listener. Use the listener variable to control other listeners.

	      Not reloaded on reload signal.

       clientid_prefixes prefix
	      If defined, only clients that have a clientid with a prefix that matches clientid_prefixes will be allowed to connect to the broker.
	      For  example, setting "secure-" here would mean a client "secure-client" could connect but another with clientid "mqtt" couldn't. By
	      default, all client ids are valid.

	      Reloaded on reload signal. Note that currently connected clients will be unaffected by any changes.

       connection_messages < true | false >
	      If set to true, the log will include entries when clients connect and disconnect. If set to false, these entries will not appear.

	      Reloaded on reload signal.

       listener port
	      Listen for incoming network connection on the specified port. A second optional argument allows the listener to be bound to  a  spe-
	      cific ip address/hostname. If this variable is used and neither bind_address nor port are used then the default listener will not be
	      started. This option may be specified multiple times. See also the mount_point option.

	      Not reloaded on reload signal.

       log_dest destinations
	      Send log messages to a particular destination.  Possible destinations are: stdout stderr syslog topic.  stdout and stderr log to the
	      console  on  the	named output.  syslog uses the userspace syslog facility which usually ends up in /var/log/messages or similar and
	      topic logs to the broker topic '$SYS/broker/log/<severity>', where severity is one of D, E, W, N, I which are debug, error, warning,
	      notice  and information. Use "log_dest none" if you wish to disable logging. Defaults to stderr. This option may be specified multi-
	      ple times.

	      Reloaded on reload signal.

       log_timestamp [ true | false ]
	      Boolean value, if set to true a timestamp value will be added to each log entry. The default is true.

	      Reloaded on reload signal.

       log_type types
	      Choose types of messages to log. Possible types are: debug, error, warning, notice, information, none. Defaults to  error,  warning,
	      notice  and  information.  This option may be specified multiple times. Note that the debug type (used for decoding incoming network
	      packets) is never logged in syslog or topics.

	      Reloaded on reload signal.

       max_connections count
	      Limit the total number of clients connected for the current listener. Set to -1 to have "unlimited"  connections.  Note  that  other
	      limits may be imposed that are outside the control of mosquitto. See e.g.  limits.conf(5).

	      Not reloaded on reload signal.

       max_inflight_messages count
	      The  maximum  number  of	QoS 1 or 2 messages that can be in the process of being transmitted simultaneously. This includes messages
	      currently going through handshakes and messages that are being retried. Defaults to 20. Set to 0 for no maximum. If set to  1,  this
	      will guarantee in-order delivery of messages.

	      Reloaded on reload signal.

       max_queued_messages count
	      The  maximum  number of QoS 1 or 2 messages to hold in the queue above those messages that are currently in flight. Defaults to 100.
	      Set to 0 for no maximum (not recommended).

	      Reloaded on reload signal.

       mount_point topic prefix
	      This option is used with the listener option to isolate groups of clients. When a client connects to a listener which uses this  op-
	      tion,  the string argument is attached to the start of all topics for this client. This prefix is removed when any messages are sent
	      to the client.  This means a client connected to a listener with mount point example can only see messages that are published in the
	      topic hierarchy example and above.

	      Not reloaded on reload signal.

       password_file file path
	      Set  the	path  to  a password file. If defined, the contents of the file are used to control client access to the broker. Each line
	      should be in the format "username:password", where the colon and password are optional but recommended. If allow_anonymous is set to
	      false,  only  users  defined  in this file will be able to connect. Setting allow_anonymous to true when password_file is defined is
	      valid and could be used with acl_file to have e.g. read only guest/anonymous accounts and defined users that can publish.

	      Reloaded on reload signal. The currently loaded username and password data will be freed and reloaded. Clients that are already con-
	      nected will not be affected.

       persistence [ true | false ]
	      Can be true or false. If true, connection, subscription and message data will be written to the disk in mosquitto.db at the location
	      dictated by persistence_location. When mosquitto is restarted, it will reload the information stored in mosquitto.db. The data  will
	      be  written to disk when mosquitto closes and also at periodic intervals as defined by autosave_interval. Writing of the persistence
	      database may also be forced by sending mosquitto the SIGUSR1 signal. If false, the data will be stored in memory only.  Defaults	to
	      false.

	      Reloaded on reload signal.

       persistence_file file name
	      The filename to use for the persistent database. Defaults to mosquitto.db.

	      Reloaded on reload signal.

       persistence_location path
	      The  path where the persistence database should be stored. Must end in a trailing slash. If not given, then the current directory is
	      used.

	      Reloaded on reload signal.

       pid_file file path
	      Write a pid file to the file specified. If not given (the default), no pid file will be written. If the pid file cannot be  written,
	      mosquitto will exit. This option only has an effect is mosquitto is run in daemon mode.

	      If  mosquitto  is being automatically started by an init script it will usually be required to write a pid file. This should then be
	      configured as /var/run/mosquitto.pid

	      Not reloaded on reload signal.

       port port number
	      Set the network port for the default listener to listen on. Defaults to 1883.

	      Not reloaded on reload signal.

       retained_persistence [ true | false ]
	      This is a synonym of the persistence option.

	      Reloaded on reload signal.

       retry_interval seconds
	      The integer number of seconds after a QoS=1 or QoS=2 message has been sent that mosquitto will wait before retrying when no response
	      is received. If unset, defaults to 20 seconds.

	      Reloaded on reload signal.

       store_clean_interval seconds
	      The integer number of seconds between the internal message store being cleaned of messages that are no longer referenced. Lower val-
	      ues will result in lower memory usage but more processor time, higher values will have the opposite effect. Setting  a  value  of  0
	      means the unreferenced messages will be disposed of as quickly as possible. Defaults to 10 seconds.

	      Reloaded on reload signal.

       sys_interval seconds
	      The  integer  number of seconds between updates of the $SYS subscription hierarchy, which provides status information about the bro-
	      ker. If unset, defaults to 10 seconds.

	      Reloaded on reload signal.

       user username
	      When run as root, change to this user and its primary group on startup. If mosquitto is unable to change to this user and group,	it
	      will  exit  with an error. The user specified must have read/write access to the persistence database if it is to be written. If run
	      as a non-root user, this setting has no effect. Defaults to mosquitto.

	      This setting has no effect on Windows and so you should run mosquitto as the user you wish it to run as.

	      Not reloaded on reload signal.

CONFIGURING BRIDGES

       Multiple bridges (connections to other brokers) can be configured using the following variables.

       Bridges cannot currently be reloaded on reload signal.

       address address[:port], addresses address[:port]
	      Specify the address and optionally the port of the bridge to connect to. This must be given for each bridge connection. If the  port
	      is not specified, the default of 1883 is used.

	      Unlike  rsmb,  it  is not currently possible to specify multiple addresses for a single bridge connection here. This is true even if
	      the name "addresses" is used.

       cleansession [ true | false ]
	      Set the clean session option for this bridge. Setting to false (the default), means that all subscriptions on the remote broker  are
	      kept in case of the network connection dropping. If set to true, all subscriptions and messages on the remote broker will be cleaned
	      up if the connection drops. Note that setting to true may cause a large amount of retained messages to be sent each time the  bridge
	      reconnects.

       clientid id
	      Set  the	client	id for this bridge connection. If not defined, this defaults to 'name.hostname', where name is the connection name
	      and hostname is the hostname of this computer.

       connection name
	      This variable marks the start of a new bridge connection. It is also used to give the bridge a name which is used as the	client	id
	      on the remote broker.

       keepalive_interval seconds
	      Set  the	number	of  seconds after which the bridge should send a ping if no other traffic has occurred.  Defaults to 60. A minimum
	      value of 5 seconds isallowed.

       idle_timeout seconds
	      Set the amount of time a bridge using the lazy start type must be idle before it will be stopped. Defaults to 60 seconds.

       notifications [ true | false ]
	      If set to true, publish notification messages to the local and remote brokers giving information about the state of the bridge  con-
	      nection. Retained messages are published to the topic $SYS/bridge/connection/<clientid>/state.  If the message is 1 then the connec-
	      tion is active, or 0 if the connection has failed. Defaults to true.

       password value
	      Configure a password for the bridge. This is used for authentication purposes when connecting to a broker that support MQTT v3.1 and
	      requires a username and/or password to connect. This option is only valid if a username is also supplied.

       start_type [ automatic | lazy | once ]
	      Set  the start type of the bridge. This controls how the bridge starts and can be one of three types: automatic, lazy and once. Note
	      that RSMB provides a fourth start type "manual" which isn't currently supported by mosquitto.

	      "automatic" is the default start type and means that the bridge connection will be started automatically when the broker starts  and
	      also restarted after a short delay (30 seconds) if the connection fails.

	      Bridges using the "lazy" start type will be started automatically when the number of queued messages exceeds the number set with the
	      "threshold" parameter. It will be stopped automatically after the time set by the "idle_timeout" parameter. Use this start  type	if
	      you wish the connection to only be active when it is needed.

	      A  bridge  using the "once" start type will be started automatically when the broker starts but will not be restarted if the connec-
	      tion fails.

       threshold count
	      Set the number of messages that need to be queued for a bridge with lazy start type to be restarted.  Defaults to 10 messages.

       topic pattern [ out | in | both ]
	      Define a topic pattern to be shared between the two brokers. Any topics matching the  pattern  (which  may  include  wildcards)  are
	      shared.  The second parameter defines the direction that the messages will be shared in, so it is possible to import messages from a
	      remote broker using "in", export messages to a remote broker using "out" or share messages in both directions. If this parameter	is
	      not defined, the default of "out" is used.

	      This option can be specified multiple times per bridge.

	      Care must be taken to ensure that loops are not created with this option. If you are experiencing high CPU load from a broker, it is
	      possible that you have a loop where each broker is forever forwarding each other the same messages.

       username name
	      Configure a username for the bridge. This is used for authentication purposes when connecting to a broker that support MQTT v3.1 and
	      requires a username and/or password to connect. See also the password option.

EXTERNAL SECURITY CHECKS

       The  following options are available when external security checks have been compiled in. Unless you have done this yourself it is unlikely
       to exist.

       db_host hostname
	      Database host name.

	      Reloaded on reload signal.

       db_port port
	      Database port.

	      Reloaded on reload signal.

       db_name name
	      Database name.

	      Reloaded on reload signal.

       db_username username
	      Database username.

	      Reloaded on reload signal.

       db_password password
	      Database password.

	      Reloaded on reload signal.

FILES

       mosquitto.conf

BUGS

       mosquitto bug information can be found at http://launchpad.net/mosquitto

SEE ALSO

       mosquitto(8) mqtt(7) limits.conf(5)

AUTHOR

       Roger Light <roger@atchoo.org>

								  5 February 2012						 mosquitto.conf(5)