What protocols are used in MQTT for message transmission and security?
MQTT relies on the TCP transport protocol. To encrypt the whole MQTT communication, many MQTT brokers (such as HiveMQ) allow use of TLS instead of plain TCP. If you use the username and password fields of the MQTT CONNECT packet for authentication and authorization mechanisms, you should strongly consider using TLS.
What is the difference between MQTT server and MQTT broker?
The MQTT protocol is based on TCP/IP. Both the client and the broker need to have a TCP/IP stack. The MQTT connection is always between one client and the broker. To initiate a connection, the client sends a CONNECT message to the broker.
Which is more secure MQTT or HTTP?
Due to its abilities, it can be found in every second IoT based device. This protocol has many features as it is over TCP and uses SSL/TLS for security….Difference between MQTT and HTTP protocols :
| Parameter | MQTT | HTTP |
|---|---|---|
| Data Security | It provides data security with SSL/TLS. | It does not provide security but Https is built for that. |
What is the purpose of retained messages in MQTT?
Retained messages is used to store the “Last Good Message” on a topic. Usually, if an MQTT client subscribes to a topic on a broker it will not recieve any of the messages published on it before subscription.
What happens if no one subscribes to a topic on MQTT?
Normally if a publisher publishes a message to a topic, and no one is subscribed to that topic the message is simply discarded by the broker. However the publisher can tell the broker to keep the last message on that topic by setting the retained message flag.
How to get rid of retained messages in Mosquitto?
A- If you’re not using the persistent database then the easiest way is to stop and restart mosquitto. Otherwise you will need to subscribe to all topics to check and clear the retained messages. You can use my Python script to do this.
Why do I need the retained message feature?
The retained message feature is useful feature for keeping the last state of an object, and is especially useful when the state doesn’t change frequently. Quality of service settings don’t impact retained messages. Please rate? And use Comments to let me know more