Provided by: mosquitto_0.15-0ubuntu1_amd64 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.

       · There are fewer configuration options.

       · There is less logging information.

       · 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:

       · 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.

       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)