In this mini-course, we will learn about subnetting. We will start small, by getting acquainted with the IPv4 address and getting to know the terms. When things are a bit clearer we start dealing with classful addressing. Classful addressing is about dividing the whole IPv4 range into 5 classes and we will be dealing with 3 of them and which was the only solution we used to use in the early days before subnetting. We will see also the private and public IP addresses. The problem is, it wasn't optimized. Then subnetting or classless addressing shows up and we start learning about its way of doing things and walk you thru the necessary steps like, how to borrow bits, how many valid IP addresses and networks will be generated. Then we will see the difference between FLSM and VLSM which is a necessity for more optimization where different subnets have a different number of hosts. Along the way, we will solve subnetting examples and quizzes to help you engage more and try out what you have learned. In the last section we will see some miscellaneous topics like, how would we know to which network this device belongs and the importance of the gateway. I hope you will enjoy this mini-course and get a thing or two from it.