In this article we will see how to setup a Mosquitto broker for implementing MQTT communication.

1. Login to Ubuntu Linux with root privileges ( sudo )

2. Add the mosquitto repository by given below commands

$sudo apt-add-repository ppa:mosquitto-dev/mosquitto-ppa
$sudo apt-get update

3. Execute the given below command to install the Mosquitto broker package

$sudo apt-get install mosquitto

4. Install Mosquitto developer libraries to develop MQTT clients

sudo apt-get install libmosquitto-dev

5. Execute the given below command to install Mosquitto client packages

$sudo apt-get install mosquitto-clients

6. Ensure that Mosquitto broker is running

$sudo service mosquitto status 

For the above command, expected result is mosquitto start/running, process 8288 where 8288 is the process id and will vary from machine to machine

7. Testing

Open a terminal and issue the given below command to subscribe the topic “mqtt”

$mosquitto_sub -h localhost -t "mqtt" -v

Open another terminal and issue the given below command to publish message to the topic “mqtt”

$mosquitto_pub -h localhost -t "mqtt" -m "Hello MQTT"

Now the message “Hello MQTT” will be displayed in the first terminal where the topic “mqtt” is subscribed.