Provided by: mosquitto_0.12-1_i386 bug


       mosquitto - an mqtt broker


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


       mosquitto is a broker for the mqtt protocol version 3.1.

       It  is intended to be a drop in replacement for rsmb, but it's a little
       way off yet.


       -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


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

       · There is only basic bridge support.

       · There are fewer configuration options.

       · There is less logging information.

       · The $SYS hierarchy is smaller.

       · 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.


       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.

              The total number of bytes received since the broker started.

              The total number of bytes sent since the broker started.

              The repository changeset (revision) associated with this build.

              The  total  number  of clients currently either connected to the
              broker or disconnected but with clean session not set.

       $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

              The number of messages currently held in the message store.

              The total number of messages received since the broker started.

              The total number of messages sent since the broker started.

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

              The amount of time in seconds the broker has been online.

              The version of the broker. Static.


       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

       · 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.


       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).


       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.

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


              Configuration file. See mosquitto.conf(5).

              Persistent message data storage location if persist enabled.

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


       mosquitto      bug      information      can      be      found      at


       mqtt(7)     mosquitto.conf(5)     hosts_access(5)      mosquitto_pub(1)
       mosquitto_sub(1) libmosquitto(3)


       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

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


       Roger Light <>

                                 25 July 2011                     mosquitto(8)