Mosquitto

Mosquitto is an open-source message broker that implements the MQTT (Message Queuing Telemetry Transport) protocol. MQTT is a lightweight messaging protocol designed for constrained devices and low-bandwidth, high-latency, or unreliable networks. It is commonly used in IoT (Internet of Things) applications, where devices need to communicate efficiently and reliably with each other or with backend systems.

Installation

Installing Mosquitto on Debian

sudo apt update

sudo apt install mosquitto mosquitto-clients

Mosquitto is installed by default at /etc/mosquitto. And you setup your config file in /etc/mosquitto/conf.d/. Note the file must end in .conf.

Example /etc/mosquitto/conf.d/_nvr.conf

Setup

Credentials

Create a new text file in /etc/mosquitto named mosquitto_passwords.txt. Inside the file add a username and password seperated by a ":" as seen in the example below.

matt:somepassword

Next you will encrypt the password by running

mosquitto_passwd -U /etc/mosquitto named mosquitto_passwords.txt

Add the following to lines to your conf file or uncomment these lines out in some cases.

allow_anonymous false
listener 1883 0.0.0.0
password_file /etc/mosquitto/mosquitto_passwords.txt

Restart Mosquitto

sudo systemctl restart mosquitto

Anonymous

Add the following to lines to your conf file or uncomment these lines out in some cases.

allow_anonymous true
listener 1883 0.0.0.0

Restart Mosquitto

sudo systemctl restart mosquitto

Testing

In two termimal windows, run the following commands to test your Mosquitto setup.

mosquitto_sub -h 127.0.0.1 -t test/events -q 1

mosquitto_pub -h 127.0.0.1 -t test/events -m "Hello World" -q 1

You should see Hello World in the output of your second terminal window. Once you see this, then you know your MQTT broker is setup correctly.

Information

Mosquitto acts as a central hub for MQTT communication, allowing devices to publish messages (publishers) and subscribe to topics to receive messages (subscribers). Here's a brief overview of Mosquitto's key features and components:

MQTT Broker: Mosquitto functions as an MQTT broker, which means it accepts incoming connections from MQTT clients (devices or applications) and routes messages between publishers and subscribers. It ensures reliable message delivery, even in challenging network conditions.
Publish-Subscribe Model: MQTT follows a publish-subscribe messaging pattern. Publishers send messages to specific topics, and subscribers receive messages from topics they are interested in. Mosquitto facilitates this communication by managing topics and forwarding messages to the appropriate subscribers.
Quality of Service (QoS): MQTT supports different levels of message delivery assurance, known as QoS levels. Mosquitto allows publishers to specify the desired QoS level when publishing messages, ensuring that messages are delivered reliably according to the chosen level of assurance.
Security: Mosquitto provides various security features to protect MQTT communication, including support for TLS (Transport Layer Security) encryption, authentication mechanisms (such as username/password or client certificates), and access control lists (ACLs) to restrict client permissions.
Persistence: Mosquitto can optionally store messages in a message store, ensuring that messages are not lost in case of network disruptions or client disconnections. This persistence feature allows subscribers to retrieve missed messages when they reconnect to the broker.
Scalability: Mosquitto is designed to be lightweight and scalable, making it suitable for deployments ranging from small-scale hobbyist projects to large-scale enterprise IoT solutions. It can handle thousands of simultaneous connections and efficiently route messages between clients.

Overall, Mosquitto is a versatile and reliable MQTT broker that facilitates efficient and secure communication between IoT devices, sensors, actuators, and backend systems in various industries and applications.

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