Practical demonstration of MQTT in action

In this section, we will look at how the communication protocol works under the hood. For this, we will use an additional software called Wireshark, which lets us capture all the incoming and outgoing MQTT packets from our broker hosted on the Raspberry Pi.

Here, we will look at how a subscriber or a publisher connects to and sends the message through our MQTT broker. So, let’s get started:

1. The first step is to install Wireshark on our Raspberry Pi. To do so, open your Terminal and type in the following command:

   sudo apt install wireshark 

It will ask you to confirm that you wish to install the package. Just type Y and press Enter. This will start the installation process. When this happens, you will see a configuration screen appear in front of you, as shown in the following screenshot. It will ask if you want to allow any user to have maximum privileges for the Wireshark application. I suggest that you choose No for...