Provided by: mosquitto_0.12-1_i386 bug


       mosquitto.conf - the configuration file for mosquitto




       mosquitto.conf  is  the configuration file for mosquitto. This file can
       reside anywhere as long as mosquitto can read it. By default, mosquitto
       does  not  need  a  configuration  file and will use the default values
       listed below. See  mosquitto(8)  for  information  on  how  to  load  a
       configuration file.


       All  lines  with  a  #  as  the  very  first character are treated as a

       Configuration lines start with a variable name. The variable  value  is
       separated from the name by a single space.


              Set  the  path  to  an access control list file. If defined, the
              contents of the file are used to control client access to topics
              on the broker.

              If  this  parameter  is defined then only the topics listed will
              have access. Topic access is added with lines of the format:

              topic [read|write] <topic>

              The access type is controlled  using  "read"  or  "write".  This
              parameter  is  optional  -  if  not  given  then  the  access is
              read/write. <topic> can contain the  +  or  #  wildcards  as  in

              The  first  set  of  topics  are  applied  to anonymous clients,
              assuming allow_anonymous is true. User specific topic  ACLs  are
              added after a user line as follows:

              user <username>

              The  username  referred to here is the same as in password_file.
              It is not the clientid.

              Reloaded on reload signal. The currently  loaded  ACLs  will  be
              freed  and  reloaded.  Existing  subscriptions  will be affected
              after the reload.

              Boolean value  that  determines  whether  clients  that  connect
              without  providing  a username are allowed to connect. If set to
              false  then  a  password  file  should  be  created   (see   the
              password_file  option)  to  control authenticated client access.
              Defaults to true.

              Reloaded on reload signal.

              The number of seconds that mosquitto will wait between each time
              it  saves  the  in-memory database to disk. If set to 0, the in-
              memory database will only be saved when mosquitto exits or  when
              receiving the SIGUSR1 signal. Note that this setting only has an
              effect if persistence is enabled. Defaults to 1800  seconds  (30

              Reloaded on reload signal.

              Listen  for  incoming  network  connections  on the specified IP
              address/hostname only. This is  useful  to  restrict  access  to
              certain  network  interfaces. To restrict access to mosquitto to
              the local host only, use  "bind_address  localhost".  This  only
              applies  to  the  default listener. Use the listener variable to
              control other listeners.

              Not reloaded on reload signal.

              If defined, only clients that have a clientid with a prefix that
              matches  clientid_prefixes  will  be  allowed  to connect to the
              broker. For example, setting "secure-" here would mean a  client
              "secure-client"  could  connect but another with clientid "mqtt"
              couldn't. By default, all client ids are valid.

              Reloaded on reload signal. Note that currently connected clients
              will be unaffected by any changes.

              Listen  for incoming network connection on the specified port. A
              second optional argument allows the listener to be  bound  to  a
              specific  ip  address/hostname.  If  this  variable  is used and
              neither bind_address nor port are used then the default listener
              will  not  be  started.  This  option  may be specified multiple
              times. See also the mount_point option.

              Not reloaded on reload signal.

              Send  log  messages  to  a  particular  destination.    Possible
              destinations are: stdout stderr syslog topic.  stdout and stderr
              log to the  console  on  the  named  output.   syslog  uses  the
              userspace   syslog   facility   which   usually   ends   up   in
              /var/log/messages or similar and topic logs to the broker  topic
              '$SYS/broker/log/<severity>',  where severity is one of D, E, W,
              N, I which are debug, error, warning,  notice  and  information.
              Use  "log_dest none" if you wish to disable logging. Defaults to
              stderr. This option may be specified multiple times.

              Reloaded on reload signal.

              Choose types of messages to  log.  Possible  types  are:  debug,
              error,  warning,  notice,  information, none. Defaults to error,
              warning, notice and information. This option  may  be  specified
              multiple  times.  Note  that  the  debug type (used for decoding
              incoming network packets) is never logged in syslog or topics.

              Reloaded on reload signal.

              Limit the total number of  clients  connected  for  the  current
              listener.  Set  to -1 to have "unlimited" connections. Note that
              other limits may be imposed that  are  outside  the  control  of
              mosquitto. See e.g.  limits.conf(5).

              Not reloaded on reload signal.

              The  maximum  number  of  QoS 1 or 2 messages that can be in the
              process  of  being  transmitted  simultaneously.  This  includes
              messages  currently  going  through handshakes and messages that
              are being retried. Defaults to 20. Set to 0 for no  maximum.  If
              set to 1, this will guarantee in-order delivery of messages.

              Reloaded on reload signal.

              The  maximum  number of QoS 1 or 2 messages to hold in the queue
              above those messages that are currently in flight.  Defaults  to
              100. Set to 0 for no maximum (not recommended).

              Reloaded on reload signal.

              This  option  is used with the listener option to isolate groups
              of clients. When a client connects to a listener which uses this
              option,  the  string  argument  is  attached to the start of all
              topics for this client. This prefix is removed when any messages
              are  sent  to  the  client.   This means a client connected to a
              listener with mount point example can only see messages that are
              published in the topic hierarchy example and above.

              Not reloaded on reload signal.

              Set the path to a password file. If defined, the contents of the
              file are used to control client access to the broker. Each  line
              should be in the format "username:password", where the colon and
              password are optional but recommended. If allow_anonymous is set
              to  false,  only  users  defined  in  this  file will be able to
              connect. Setting allow_anonymous to true when  password_file  is
              defined  is  valid  and could be used with acl_file to have e.g.
              read only guest/anonymous accounts and defined  users  that  can

              Reloaded  on  reload  signal.  The currently loaded username and
              password data will be  freed  and  reloaded.  Clients  that  are
              already connected will not be affected.

              Can  be  true  or  false.  If true, connection, subscription and
              message data will be written to the disk in mosquitto.db at  the
              location  dictated  by  persistence_location.  When mosquitto is
              restarted,  it   will   reload   the   information   stored   in
              mosquitto.db.  The  data  will be written to disk when mosquitto
              closes  and  also  at   periodic   intervals   as   defined   by
              autosave_interval.  Writing of the persistence database may also
              be forced by sending mosquitto the SIGUSR1 signal. If false, the
              data will be stored in memory only. Defaults to false.

              Reloaded on reload signal.

              The  filename  to  use  for the persistent database. Defaults to

              Reloaded on reload signal.

              The path where the persistence database should be  stored.  Must
              end  in  a  trailing  slash.  If  not  given,  then  the current
              directory is used.

              Reloaded on reload signal.

              Write a pid file to  the  file  specified.  If  not  given  (the
              default), no pid file will be written. If the pid file cannot be
              written, mosquitto will exit. This option only has an effect  is
              mosquitto is run in daemon mode.

              If mosquitto is being automatically started by an init script it
              will usually be required to write a pid file. This  should  then
              be configured as /var/run/

              Not reloaded on reload signal.

       port   Set  the  network  port  for  the default listener to listen on.
              Defaults to 1883.

              Not reloaded on reload signal.

              This is a synonym of the persistence option.

              Reloaded on reload signal.

              The integer number of seconds after a QoS=1 or QoS=2 message has
              been  sent  that  mosquitto  will  wait  before retrying when no
              response is received. If unset, defaults to 20 seconds.

              Reloaded on reload signal.

              The integer number of seconds between the internal message store
              being  cleaned  of messages that are no longer referenced. Lower
              values will result in lower  memory  usage  but  more  processor
              time,  higher  values  will  have the opposite effect. Setting a
              value of 0 means the unreferenced messages will be  disposed  of
              as quickly as possible. Defaults to 10 seconds.

              Reloaded on reload signal.

              The  integer  number  of  seconds  between  updates  of the $SYS
              subscription hierarchy, which provides status information  about
              the broker. If unset, defaults to 10 seconds.

              Reloaded on reload signal.

       user   When  run  as root, change to this user and its primary group on
              startup. If mosquitto is unable  to  change  to  this  user  and
              group,  it will exit with an error. The user specified must have
              read/write access to the persistence database if  it  is  to  be
              written.  If run as a non-root user, this setting has no effect.
              Defaults to mosquitto.

              This setting has no effect on Windows  and  so  you  should  run
              mosquitto as the user you wish it to run as.

              Not reloaded on reload signal.


       Multiple bridges (connections to other brokers) can be configured using
       the following variables.

       Bridges cannot currently be reloaded on reload signal.

       address address[:port], addresses address[:port]
              Specify the address and optionally the port  of  the  bridge  to
              connect  to.  This  must be given for each bridge connection. If
              the port is not specified, the default of 1883 is used.

              Unlike rsmb, it is not currently possible  to  specify  multiple
              addresses for a single bridge connection here. This is true even
              if the name "addresses" is used.

       cleansession [ true | false ]
              Set the clean session option for this bridge. Setting  to  false
              (the default), means that all subscriptions on the remote broker
              are kept in case of the network connection dropping. If  set  to
              true,  all  subscriptions and messages on the remote broker will
              be cleaned up if the connection drops. Note that setting to true
              may  cause  a  large amount of retained messages to be sent each
              time the bridge reconnects.

       clientid id
              Set the client id for this bridge connection.  If  not  defined,
              this  defaults  to 'name.hostname', where name is the connection
              name and hostname is the hostname of this computer.

       connection name
              This variable marks the start of a new bridge connection. It  is
              also  used to give the bridge a name which is used as the client
              id on the remote broker.

       keepalive_interval seconds
              Set the number of seconds after which the bridge should  send  a
              ping  if  no  other  traffic  has  occurred.   Defaults to 60. A
              minimum value of 5 seconds isallowed.

       password value
              Configure  a  password  for  the  bridge.  This  is   used   for
              authentication purposes when connecting to a broker that support
              MQTT v3.1 and requires a username and/or  password  to  connect.
              This option is only valid if a username is also supplied.

       topic pattern [ out | in | both ]
              Define a topic pattern to be shared between the two brokers. Any
              topics matching the pattern (which may  include  wildcards)  are
              shared.  The  second  parameter  defines  the direction that the
              messages will be shared in, so it is possible to import messages
              from  a  remote  broker  using "in", export messages to a remote
              broker using "out" or share messages in both directions. If this
              parameter is not defined, the default of "out" is used.

              This option can be specified multiple times per bridge.

              Care  must  be  taken  to ensure that loops are not created with
              this option. If you  are  experiencing  high  CPU  load  from  a
              broker, it is possible that you have a loop where each broker is
              forever forwarding each other the same messages.

       username name
              Configure  a  username  for  the  bridge.  This  is   used   for
              authentication purposes when connecting to a broker that support
              MQTT v3.1 and requires a username and/or  password  to  connect.
              See also the password option.


       The  following options are available when external security checks have
       been compiled in. Unless you have done this yourself it is unlikely  to

       db_host hostname
              Database host name.

              Reloaded on reload signal.

       db_port port
              Database port.

              Reloaded on reload signal.

       db_name name
              Database name.

              Reloaded on reload signal.

       db_username username
              Database username.

              Reloaded on reload signal.

       db_password password
              Database password.

              Reloaded on reload signal.




       mosquitto      bug      information      can      be      found      at


       mosquitto(8) mqtt(7) limits.conf(5)


       Roger Light <>

                                 25 July 2011                mosquitto.conf(5)