From the author of Amazon best selling book 'Subnetting Secrets.'

Subnetting questions are included in almost every IT exam including Microsoft, Cisco, Amazon, Juniper, CompTIA and many others. After over 16 years teaching and working in IT I’ve found that it’s the weakest area for every IT professional.

Subnetting questions are asked in technical job interviews and will form part of your day-to-day job if you work in the technical side of IT such as networking, cloud, security and even programming.

You need to be able to answer subnetting questions both accurately and quickly if you are to pass your IT exams and technical interviews. Questions such as:

How many subnets and hosts per subnet can you get from the network 172.16.0.0/18

 or

 You are given IP address 172.21.45.143/22. What is the first valid host address on this subnet?

 If it takes you more than around 60 seconds to answer these questions then you need to brush up on your subnetting skills. They start to go rusty if you don’t keep on top of it.

This is not a subnetting tutorial, it’s four exam style subnetting questions. Check out the IP Subnetting Courses on Udemy such as

Subnetting Secrets' if you want to learn it.