Practice Subnetting IPv4:

Target IP address . . . /

IP address Check/Show Answer Correct?
Network . . . . . .
First Host . . . . . .
Last Host . . . . . .
Broadcast . . . . . .
Next Subnet . . . . . .
Check or Show ALL


Learn Subnetting IPv4:

Subnetting Mastery Video Series

This video series will teach you everything you need to know about Subnetting.

To maximize your retention, it is recommended to watch these videos in order, and take a quick practice break after video 4, video 5, and video 7.

In Video 1, you will learn the basics of subnetting. Every Subnetting problem will ask you to solve for one or more of seven possible attributes. This video explains what each of the attributes are.
In Video 2 of the series, we will show you how to draw the ultimate Subnetting Cheat Sheet. The rest of the videos in this series will show you how to use this Cheat Sheet to answer any subnetting problem in 60 seconds or less.
In Video 3, we will show you how to use the Subnetting Cheat Sheet to solve for all seven attributes of Subnetting (explored in video 1) in 60 seconds or less.
In Video 4 there are four more practice problems to provide further demonstrations of the method and cheat sheet. The first two problems are fairly straight forward. The second two demonstrate a couple specific peculiarities you might encounter in the real world.
In Video 5, we will show you four tricks that will help you solve subnetting problems even faster. With the speed tips in this video, and a little practice, it won't be unreasonable to be able to solve subnetting questions in as little as 10 seconds.
In Video 6, we show you how to extend the Subnetting Cheat Sheet to allow you to solve problems in the /17-/24 range just as easily as the /25-/32 range.
In Video 7, we show you how to extend the Subnetting Cheat Sheet to allow you to solve problems in the /1-/16 range.
In Part 1 of the FLSM and VLSM Appendix, we explain the Network Doubling logic, and use it to show you how to solve two types of FLSM questions. Then we illustrate 2^N notation, and demonstrate how to use it to answer FLSM questions quickly.
In Part 2 of the FLSM and VLSM Appendix, we unpack Variable Length Subnet Mask questions, and illustrate how to solve them. We then step through a series of examples using VLSM to assign IP addresses to a network.
Supernetting involves taking multiple subnets or IP addresses and aggregating them into a single Network. This video illustrates and discusses the process, and shows you how to solve summarization problems quickly and accurately. The terms Supernetting, IP Aggregation, and IP Summarization are all interchangible

--- presented by ---

Visit for more free resources to learn
Network Engineering and Network Security.

Studying for the CCNA? Check out for a list of free, high quality training resources covering various CCNA topics

Want to learn the core of networking: How Data flows through a network? Check out the Networking Fundamentals video series