mosquitto

Some notes I wish existed in my MQTT journey

Mosquitto is a useful messaging protocol which can publish and subscribe messages to various hosts. These messages can be text, sensor data, and all kinds of other things.

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tips / warnings

• migrating to 2.0
• Don't let the cuteness fool you - Exploiting IoT's MQTT protocol + DEMO
• Internet of Telemetry: I Know What You Did Last Lockdown
  • Internet of Telemetry: I Know What You Did Last Lockdown
• subscribe to everything on the broker:
  mosquitto_sub -h some.host -p 8883 --capath /etc/ssl/certs/ -t "#" -v
• also useful: Topics starting with $ should be hidden from wildcard subscriptions like #
• use ssl, beware the error messages will be hopeless
• To remove a retained message, send a new empty message with:
  mosquitto_pub -t <topic> -r -n

using with collected and rrdtool

SSL error messages weren't very helpful

• Interval 60 - required

<LoadPlugin mqtt>
    Interval 60
</LoadPlugin>

• CACert /etc/ssl/certs/ca-certificates.crt -- required if you have a public facing ssl cert
• types.db
  It needs to know what kind of topic you're seeing.
  I got lucky and had temperature, pressure, and humidity in the defaults but not dewpoint which leads to this logfile error.
  mqtt plugin: Unknown type: "dewpoint".
  The solution, create a /etc/collectd/my_types.db and add that to your collectd.conf:
  dewpoint value:GAUGE:U:U
• make sure your ipv6 address works too

TODO

• describe authentication
  • mosquitto.conf
  • mosquitto_passwd
  • dynamic-security
• websockets
  • jpmens websockets
  • hivemq websockets