Paho Python MQTT Client – Publish With Examples

In this tutorial we will look at how you publish messages using the Paho Python MQTT client. We will use an example python script to publish messages, process the publish acknowledgements and examine QOS (quality of service) settings. Important Note feb 2024: The MQTT Python client has been upgraded to version 2.The code examples were written in version 1.5 . The change appears only to affect the callbacks which now have a properties field. This is for MQTTv5 compliance. You may need to add this to the callbacks in the examples. Tks matt. To publish a messages you use the

Continue reading

Understanding The Domain Name Structure

To understand the domain name structure you really need to understand the problem the structure was meant to solve. The Domain Name Structure and Domain Name System were developed to organise and find the IP addresses of Computers on large distributed networks.

Continue reading

Understanding HTTP Basics

HTTP stands for hypertext transfer protocol and is used to transfer data across the Web. It is a critical protocol for web developers to understand and because of it widespread use it is also used in transferring data and commands in IOT applications. The first version of the protocol had only one method, namely GET, which would request a page from a server. The response from the server was always an HTML page.- Wiki To give you an idea of how simple the HTTP protocol started out take a look at the Original specification which was only 1 page.

Continue reading

How to Use Nslookup – Beginners Guide

nslookup is a network administration command-line tool available for many computer operating systems. It is used for querying the Domain Name System (DNS) to obtain domain name or IP address mapping information .- Wiki

Continue reading

Understanding DNS – Beginners Guide to DNS

DNS (Domain Name System) is one of the most important technologies/services on the internet, as without it the Internet would be very difficult to use. DNS provides a name to number (IP address) mapping or translation, allowing internet users to use, easy to remember names, and not numbers to access resources on a network and the Internet.

Continue reading

TCP/IP Ports and Sockets Explained

On a TCP/IP network every device must have an IP address. The IP address identifies the device e.g. computer. However an IP address alone is not sufficient for running network applications, as a computer can run multiple applications and/or services. Just as the IP address identifies the computer, The network port identifies the application or service running on the computer. The use of ports allow computers/devices to run multiple services/applications. The diagram below shows a computer to computer connection and identifies the IP addresses and ports.

Continue reading

The TCP/IP Model and Protocol Suite Explained for Beginners

Any one starting to learn about computer networking will be faced with learning about the OSI and TCP/IP networking models, and the TCP/IP protocol suite. In this tutorial we will look at networking protocol models, and explain how and why they are structured into layers. We will then look at the most common protocol suite, the TCP/IP protocol suite and the 4 layer model.

Continue reading

Beginners Guide to Bluetooth

Bluetooth is a wireless networking protocol (like WIFI) designed to quickly and automatically connect devices like printers, PDAs, Cameras etc to computers and to each other without wires. Common Bluetooth applications are: Connecting mobile phones to each other to exchange pictures,ring tones, music etc Connecting computer peripherals like mice, keyboards, printers etc to a computer. Connecting headsets to mobile phones for hands free operation (Bluetooth car kits)

Continue reading

Binary Numbers Explained – Beginners Guide

In my experience of teaching networking many students struggle with IP addresses because they lack an basic understanding of binary numbers. An understanding of binary numbers,the binary system, and how to convert between binary and decimal is essential for anyone involved in computers, coding, and networking.

Continue reading