Provided by: mosquitto_0.12-1_i386
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.
Load configuration from a file. If not given, the default values
as described in mosquitto.conf(5) are used.
Run mosquitto in the background as a daemon. All other behaviour
remains the same.
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.
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
The amount of time in seconds the broker has been online.
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
The following subscriptions will not match:
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:
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.
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)
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 <firstname.lastname@example.org>
25 July 2011 mosquitto(8)