How to Install and Secure the Mosquitto MQTT Messaging Broker

MQTT is a machine-to-machine messaging protocol, designed to provide lightweight publish/subscribe communication to “Internet of Things” devices. Mosquitto is a popular MQTT server (or broker, in MQTT parlance) that has great community support and is easy to install and configure. In this tutorial, we’ll install Mosquitto, retrieve SSL certificates from Let’s Encrypt, and set up our broker to use SSL to secure our password-protected MQTT communications.