![\"Mosquitto](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/01\/Mosquitto-MQTT-Client-Rpi.jpg?resize=1200%2C675&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\nUpdated 23 February 2023<\/em><\/p>\n\n\n\n Recommended resources:<\/strong><\/p>\n\n\n\n After installing MQTT Broker<\/a>, I recommend installing an MQTT Client to test the Broker installation and publish sample messages.<\/p>\n\n\n\n Run the following command to install MQTT Mosquitto Client:<\/p>\n\n\n\n Run Mosquitto in the background as a daemon:<\/p>\n\n\n\n To subscribe to an MQTT topic with Mosquitto Client open a terminal Window #1 and enter the command:<\/p>\n\n\n\n You’re now subscribed to a topic called testTopic<\/strong><\/span>.<\/p>\n\n\n\n If you have enabled username and password on your broker<\/strong>, you need to run the command as follows:<\/p>\n\n\n\n Replace user <\/strong>with your username and pass<\/strong> with your password. For example, my username is sara<\/span> and the password is pass1245<\/span>, so I need to run the command as follows:<\/p>\n\n\n\n To publish a sample message to testTopic<\/strong><\/span>, open a terminal Window #2 and run the following command:<\/p>\n\n\n\n The message “Hello World!<\/strong>” is received in Window #1 as illustrated in the figure above.<\/p>\n\n\n\n If you have enabled username and password on your broker<\/strong>, you need to run the command as follows:<\/p>\n\n\n\n Replace user <\/strong>with your username and pass <\/strong>with your password.<\/p>\n\n\n\n Having Window #1 still subscribed to topic testTopic<\/strong><\/span>, open a new terminal Window #3 and run this command to subscribe to testTopic<\/strong><\/span> topic:<\/p>\n\n\n\n If you have enabled username and password on your broker, you need to run the command as follows:<\/p>\n\n\n\n Replace user <\/strong>with your username and pass <\/strong>with your password.<\/p>\n\n\n\n On Window #2 publish the “Hello World!<\/strong>” message:<\/p>\n\n\n\n If you have enabled username and password on your broker, you need to run the command as follows:<\/p>\n\n\n\n Since two clients are subscribed to testTopic<\/strong><\/span> topic, they will both receive the “Hello world!”<\/strong> message.<\/p>\n\n\n\n This simple example shows how MQTT works and how your devices (for example: ESP8266 <\/a>or ESP32<\/a>, etc.) can be subscribed to the same topic to receive messages, or a device can publish messages to multiple devices.<\/p>\n\n\n\n In this tutorial, you checked that your Mosquitto Broker installed on the Raspberry Pi is running properly. Now, you can experiment with MQTT in your ESP32\/ESP8266 IoT projects. We have several MQTT practical examples that you can experiment with. Here are some examples:<\/p>\n\n\n\n You can also run Mosquitto MQTT broker on the cloud. Running an MQTT Mosquitto Broker in the cloud allows you to connect several ESP32\/ESP8266 boards and other IoT devices from anywhere using different networks as long as they have an Internet connection. Check the tutorial below:<\/p>\n\n\n\n Do you want to learn more about Home Automation? Learn Node-RED<\/strong> and InfluxDB<\/strong> on a Raspberry Pi<\/strong> to build a Home Automation System with the ESP32<\/strong> and ESP8266<\/strong>. Check out our eBook: <\/p>\n\n\n\n Do you have any questions? <\/strong>Leave a comment down below!<\/strong><\/p>\n\n\n\n Thanks for reading. If you like this post probably you might like my next ones, so please support me by subscribing to my blog<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":" In this tutorial, you\u2019re going to test the Mosquitto MQTT Broker and MQTT Client on a Raspberry Pi. You’ll subscribe the MQTT client to an MQTT topic and publish sample messages. … <\/p>\n\n
Testing MQTT Broker Installation<\/h2>\n\n\n\n
sudo apt install -y mosquitto mosquitto-clients<\/code><\/pre>\n\n\n\nmosquitto -d<\/code><\/pre>\n\n\n\nSubscribing to testTopic<\/em> Topic<\/h3>\n\n\n\n
mosquitto_sub -d -t testTopic<\/code><\/pre>\n\n\n![\"Mosquitto](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/01\/Mosquitto-MQTT-Client-subscribe-topic.png?resize=661%2C161&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\nmosquitto_sub -d -t testTopic -u user <\/strong>-P pass<\/strong><\/code><\/pre>\n\n\n\nmosquitto_sub -d -t testTopic -u sara <\/strong>-P pass1245<\/strong><\/code><\/pre>\n\n\n\nPublishing “Hello World!” Message to testTopic <\/em>Topic<\/h3>\n\n\n\n
mosquitto_pub -d -t testTopic -m \"Hello world!\"<\/code><\/pre>\n\n\n![\"\"](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/01\/mosquitto_pub.png?resize=720%2C441&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\nmosquitto_pub -d -t testTopic -m \"Hello world!\" -u user <\/strong>-P pass<\/strong><\/code><\/pre>\n\n\n\nPublishing a Message to Multiple Clients<\/h3>\n\n\n\n
mosquitto_sub -d -t testTopic<\/code><\/pre>\n\n\n\nmosquitto_sub -d -t testTopic -u user <\/strong>-P pass<\/strong><\/code><\/pre>\n\n\n\nmosquitto_pub -d -t testTopic -m \"Hello world!\"<\/code><\/pre>\n\n\n\nmosquitto_pub -d -t testTopic -m \"Hello world!\" -u user <\/strong>-P pass<\/strong><\/code><\/pre>\n\n\n![\"\"](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/01\/mosquitto_2_sub_one_published.png?resize=716%2C745&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\nWrapping Up<\/h2>\n\n\n\n
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