- For each Target IP, solve for the Network ID, First Host IP, Last Host IP, Broadcast IP, and Next Network
- To learn how to Subnet watch the Subnetting Mastery free training series listed below
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Keyboard Shortcuts (desktop only)
- Press . or / in any input box to jump to the next box
- Press [ENTER] to cycle through Check All -> Show All -> Next Problem
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.
What is Subnetting?
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.Watch Video on YouTube
Subnetting Cheat Sheet
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.Watch Video on YouTube
How to solve ANY Subnetting Problem?
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.Watch Video on YouTube
Practice Problems
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.Watch Video on YouTube
Speed Tips & Tricks
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.Watch Video on YouTube
Subnetting in the /17 - /24 Range
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.Watch Video on YouTube
Subnetting in the /1 - /16 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.Watch Video on YouTube
FLSM and VLSM Appendix
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.Watch Video on YouTube
FLSM and VLSM Appendix
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.Watch Video on YouTube
Supernetting & IP Summarization
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 interchangibleWatch Video on YouTube