Provided by: mosquitto_0.15-0ubuntu1_i386 bug

NAME

       mosquitto - an mqtt broker

SYNOPSIS

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

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.

LIMITATIONS

       mosquitto  implements  all  of the mqtt protocol version 3.1, but there
       are some limitations compared to rsmb.

       o There are fewer configuration options.

       o There is less logging information.

       o It isn't as well tested or documented...

       It should be noted that  all  of  the  above  limitations  should  have
       "currently" included in them. They will all be fixed at some point.

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.

       $SYS/broker/bytes/per second/received
              The average number of bytes received per second since the broker
              started.

       $SYS/broker/bytes/per second/sent
              The  average  number  of  bytes sent per second since the broker
              started.

       $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/changeset
              The repository changeset (revision) associated with this  build.
              Static.

       $SYS/broker/clients/active
              The number of currently connected clients

       $SYS/broker/clients/inactive
              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 active clients that have been connected to
              the broker. This is only calculated when the $SYS topic tree  is
              updated, so short lived client connections may not be counted.

       $SYS/broker/clients/total
              The  total  number  of active clients currently connected to the
              broker.

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

       $SYS/broker/messages/per second/received
              The average number of messages received  per  second  since  the
              broker started.

       $SYS/broker/messages/per second/sent
              The  average number of messages sent per second since the broker
              started.

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

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

       $SYS/broker/messages/stored
              The number of messages currently held in the message store.

       $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:

       o a/b/c/d

       o +/b/c/d

       o a/+/c/d

       o a/+/+/d

       o +/+/+/+

       The following subscriptions will not match:

       o a/b/c

       o b/+/c/d

       o +/+/+

       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:

       o a/b/c/d

       o #

       o a/#

       o a/b/#

       o a/b/c/#

       o +/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.

       SIGHUP Upon receiving the SIGHUP  signal,  mosquitto  will  attempt  to
              reload  its  configuration. Not all configuration parameters can
              be  reloaded  without  a  restart.  See  mosquitto.conf(5)   for
              details.

       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
       http://launchpad.net/mosquitto

SEE ALSO

       mqtt(7)     mosquitto.conf(5)     hosts_access(5)      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  and  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>

                                5 February 2012                   mosquitto(8)