Public MQTT Brokers

Cloud Based Implementation of IoT Using MQTT Brokers

This is a useful article that sums up the various MQTT options.

https://www.opensourceforu.com/2020/10/cloud-based-implementation-of-iot-using-mqtt-brokers/

When using public brokers, it is advised to consider encrypting traffic as standard. Both topics and payloads can be encrypted, with Node-RED providing nodes for such operations. Only devices that have the encryption key can find (subscribe) and make sense of the data.

The interesting question to ask is if public brokers are as good as a dedicated private broker.

Using public brokers has the following advantages:

• A central list can be maintained (the table below can be loaded into software from this site)
• With three or more brokers reliably available, one can establish primary and secondary routes, adding resilience and making for increased reliability
• No maintenance, and no costs. A completely free approach to communications. (Note that running your own MQTT broker is free).

Disadvantages:

• Topics and payloads need securing and separating from other traffic
• Not saleable for commercial use

The following additional measures should be implemented:

• Data should be encrypted is any way private.
• Topics should be adjusted to a log and unique identifier to separate from other traffic on the public server.
• Topics and payloads can be encrypted in an object along with a timestamp, and then all messages can be sent over a single unique identifier.

In summary, public servers are good for projects and for setting up systems. Once they need to be scaled commercially then a private MQTT server should be used.

Public MQTT servers are probably best as backup routes when a commercial server falls down, only initiated when needed, and closed when normal connections resume.

Public MQTT Brokers

Name	Broker Address	TCP Port	TLS Port	WebSocket Port	Message Retention	Persistent Session	Sign Up Requred	Link
Eclipse	mqtt.eclipse.org	1883	N/A	80, 443	YES	YES	NO	http://iot.eclipse.org/sandbox.html
Mosquitto	test.mosquitto.org	1883	8883, 8884	80	YES	YES	NO	https://test.mosquitto.org/
HiveMQ	broker.hivemq.com	1883	N/A	8000	YES	YES	NO	https://www.hivemq.com/try-out/
Flespi	mqtt.flespi.io	1883	8883	80, 443	YES	YES	YES	https://flespi.com/mqtt-broker
Dioty	mqtt.dioty.co	1883	8883	8080, 8880	YES	YES	YES	http://www.dioty.co/
Fluux	mqtt.fluux.io	1883	8883	N/A	N/A	N/A	NO	https://fluux.io/
EMQX	broker.emqx.io	1883	8883	8083	YES	YES	NO	https://emqx.io/

EMQX Public MQTT 5 Broker

• https://www.emqx.com/en/mqtt/public-mqtt5-broker

Node-RED Automation

Node-RED version 2 now allows one to manage MQTT subscriptions at run time through software, allowing the processes of encryption and subscribing to be automated.

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