Provided by: mosquitto_1.4.8-1build1_i386 bug

NAME

       mosquitto - an MQTT broker

SYNOPSIS

       mosquitto [-c config file] [-d | --daemon] [-p port number] [-v]

DESCRIPTION

       mosquitto is a broker for the MQTT protocol version 3.1.

OPTIONS

       -c, --config-file
           Load configuration from a file. If not given, the default values as
           described in mosquitto.conf(5) are used.

       -d, --daemon
           Run mosquitto in the background as a daemon. All other behaviour
           remains the same.

       -p, --port
           Listen on the port specified instead of the default 1883. This acts
           in addition to the port setting in the config file. May be
           specified multiple times to open multiple sockets listening on
           different ports. This socket will be bound to all network
           interfaces.

       -v, --verbose
           Use verbose logging. This is equivalent to setting log_type to all
           in the configuration file. This overrides and logging options given
           in the configuration file.

CONFIGURATION

       The broker can be configured using a configuration file as described in
       mosquitto.conf(5) and this is the main point of information for
       mosquitto. The files required for SSL/TLS support are described in
       mosquitto-tls(7).

BROKER STATUS

       Clients can find information about the broker by subscribing to topics
       in the $SYS hierarchy as follows. Topics marked as static are only sent
       once per client on subscription. All other topics are updated every
       sys_interval seconds. If sys_interval is 0, then updates are not sent.

       Note that if you are using a command line client to interact with the
       $SYS topics and your shell interprets $ as an environment variable, you
       need to place the topic in single quotes '$SYS/...' or to escape the
       dollar symbol: \$SYS/... otherwise the $SYS will be treated as an
       environment variable.

       $SYS/broker/bytes/received
           The total number of bytes received since the broker started.

       $SYS/broker/bytes/sent
           The total number of bytes sent since the broker started.

       $SYS/broker/clients/connected, $SYS/broker/clients/active (deprecated)
           The number of currently connected clients.

       $SYS/broker/clients/expired
           The number of disconnected persistent clients that have been
           expired and removed through the persistent_client_expiration
           option.

       $SYS/broker/clients/disconnected, $SYS/broker/clients/inactive
       (deprecated)
           The total number of persistent clients (with clean session
           disabled) that are registered at the broker but are currently
           disconnected.

       $SYS/broker/clients/maximum
           The maximum number of clients that have been connected to the
           broker at the same time.

       $SYS/broker/clients/total
           The total number of active and inactive clients currently connected
           and registered on the broker.

       $SYS/broker/connection/#
           When bridges are configured to/from the broker, common practice is
           to provide a status topic that indicates the state of the
           connection. This is provided within $SYS/broker/connection/ by
           default. If the value of the topic is 1 the connection is active,
           if 0 then it is not active. See the Bridges section below for more
           information on bridges.

       $SYS/broker/heap/current size
           The current size of the heap memory in use by mosquitto. Note that
           this topic may be unavailable depending on compile time options.

       $SYS/broker/heap/maximum size
           The largest amount of heap memory used by mosquitto. Note that this
           topic may be unavailable depending on compile time options.

       $SYS/broker/load/connections/+
           The moving average of the number of CONNECT packets received by the
           broker over different time intervals. The final "+" of the
           hierarchy can be 1min, 5min or 15min. The value returned represents
           the number of connections received in 1 minute, averaged over 1, 5
           or 15 minutes.

       $SYS/broker/load/bytes/received/+
           The moving average of the number of bytes received by the broker
           over different time intervals. The final "+" of the hierarchy can
           be 1min, 5min or 15min. The value returned represents the number of
           bytes received in 1 minute, averaged over 1, 5 or 15 minutes.

       $SYS/broker/load/bytes/sent/+
           The moving average of the number of bytes sent by the broker over
           different time intervals. The final "+" of the hierarchy can be
           1min, 5min or 15min. The value returned represents the number of
           bytes sent in 1 minute, averaged over 1, 5 or 15 minutes.

       $SYS/broker/load/messages/received/+
           The moving average of the number of all types of MQTT messages
           received by the broker over different time intervals. The final "+"
           of the hierarchy can be 1min, 5min or 15min. The value returned
           represents the number of messages received in 1 minute, averaged
           over 1, 5 or 15 minutes.

       $SYS/broker/load/messages/sent/+
           The moving average of the number of all types of MQTT messages sent
           by the broker over different time intervals. The final "+" of the
           hierarchy can be 1min, 5min or 15min. The value returned represents
           the number of messages send in 1 minute, averaged over 1, 5 or 15
           minutes.

       $SYS/broker/load/publish/dropped/+
           The moving average of the number of publish messages dropped by the
           broker over different time intervals. This shows the rate at which
           durable clients that are disconnected are losing messages. The
           final "+" of the hierarchy can be 1min, 5min or 15min. The value
           returned represents the number of messages dropped in 1 minute,
           averaged over 1, 5 or 15 minutes.

       $SYS/broker/load/publish/received/+
           The moving average of the number of publish messages received by
           the broker over different time intervals. The final "+" of the
           hierarchy can be 1min, 5min or 15min. The value returned represents
           the number of publish messages received in 1 minute, averaged over
           1, 5 or 15 minutes.

       $SYS/broker/load/publish/sent/+
           The moving average of the number of publish messages sent by the
           broker over different time intervals. The final "+" of the
           hierarchy can be 1min, 5min or 15min. The value returned represents
           the number of publish messages sent in 1 minute, averaged over 1, 5
           or 15 minutes.

       $SYS/broker/load/sockets/+
           The moving average of the number of socket connections opened to
           the broker over different time intervals. The final "+" of the
           hierarchy can be 1min, 5min or 15min. The value returned represents
           the number of socket connections in 1 minute, averaged over 1, 5 or
           15 minutes.

       $SYS/broker/messages/inflight
           The number of messages with QoS>0 that are awaiting
           acknowledgments.

       $SYS/broker/messages/received
           The total number of messages of any type received since the broker
           started.

       $SYS/broker/messages/sent
           The total number of messages of any type sent since the broker
           started.

       $SYS/broker/messages/stored
           The number of messages currently held in the message store. This
           includes retained messages and messages queued for durable clients.

       $SYS/broker/publish/messages/dropped
           The total number of publish messages that have been dropped due to
           inflight/queuing limits. See the max_inflight_messages and
           max_queued_messages options in mosquitto.conf(5) for more
           information.

       $SYS/broker/publish/messages/received
           The total number of PUBLISH messages received since the broker
           started.

       $SYS/broker/publish/messages/sent
           The total number of PUBLISH messages sent since the broker started.

       $SYS/broker/retained messages/count
           The total number of retained messages active on the broker.

       $SYS/broker/subscriptions/count
           The total number of subscriptions active on the broker.

       $SYS/broker/timestamp
           The timestamp at which this particular build of the broker was
           made. Static.

       $SYS/broker/uptime
           The amount of time in seconds the broker has been online.

       $SYS/broker/version
           The version of the broker. Static.

WILDCARD TOPIC SUBSCRIPTIONS

       In addition to allowing clients to subscribe to specific topics,
       mosquitto also allows the use of two wildcards in subscriptions.  + is
       the wildcard used to match a single level of hierarchy. For example,
       for a topic of "a/b/c/d", the following example subscriptions will
       match:

       ·   a/b/c/d

       ·   +/b/c/d

       ·   a/+/c/d

       ·   a/+/+/d

       ·   +/+/+/+

       The following subscriptions will not match:

       ·   a/b/c

       ·   b/+/c/d

       ·   +/+/+

       The second wildcard is # and is used to match all subsequent levels of
       hierarchy. With a topic of "a/b/c/d", the following example
       subscriptions will match:

       ·   a/b/c/d

       ·   #

       ·   a/#

       ·   a/b/#

       ·   a/b/c/#

       ·   +/b/c/#

       The $SYS hierarchy does not match a subscription of "#". If you want to
       observe the entire $SYS hierarchy, subscribe to $SYS/#.

       Note that the wildcards must be only ever used on their own, so a
       subscription of "a/b+/c" is not valid use of a wildcard. The # wildcard
       must only ever be used as the final character of a subscription.

BRIDGES

       Multiple brokers can be connected together with the bridging
       functionality. This is useful where it is desirable to share
       information between locations, but where not all of the information
       needs to be shared. An example could be where a number of users are
       running a broker to help record power usage and for a number of other
       reasons. The power usage could be shared through bridging all of the
       user brokers to a common broker, allowing the power usage of all users
       to be collected and compared. The other information would remain local
       to each broker.

       For information on configuring bridges, see mosquitto.conf(5).

SIGNALS

       SIGHUP
           Upon receiving the SIGHUP signal, mosquitto will attempt to reload
           configuration file data, assuming that the -c argument was provided
           when mosquitto was started. Not all configuration parameters can be
           reloaded without restarting. See mosquitto.conf(5) for details.

       SIGUSR1
           Upon receiving the SIGUSR1 signal, mosquitto will write the
           persistence database to disk. This signal is only acted upon if
           persistence is enabled.

       SIGUSR2
           The SIGUSR2 signal causes mosquitto to print out the current
           subscription tree, along with information about where retained
           messages exist. This is intended as a testing feature only and may
           be removed at any time.

FILES

       /etc/mosquitto/mosquitto.conf
           Configuration file. See mosquitto.conf(5).

       /var/lib/mosquitto/mosquitto.db
           Persistent message data storage location if persist enabled.

       /etc/hosts.allow, /etc/hosts.deny
           Host access control via tcp-wrappers as described in
           hosts_access(5).

BUGS

       mosquitto bug information can be found at
       https://bugs.eclipse.org/bugs/describecomponents.cgi?product=Mosquitto

SEE ALSO

       mqtt(7), mosquitto-tls(7), mosquitto.conf(5), hosts_access(5),
       mosquitto_passwd(1), mosquitto_pub(1), mosquitto_sub(1),
       libmosquitto(3)

THANKS

       Thanks to Andy Stanford-Clark for being one of the people who came up
       with MQTT in the first place. Thanks to Andy and Nicholas O'Leary for
       providing clarifications of the protocol.

       Thanks also to everybody at the Ubuntu UK Podcast and Linux Outlaws for
       organising OggCamp, where Andy gave a talk that inspired mosquitto.

AUTHOR

       Roger Light <roger@atchoo.org>