Subnetting Secrets

The book I read to research this post was Subnetting Secrets by Paul Browning which is an excellent book that I read at kindle unlimited. This book explains the subject in easy to understand terms. It is around 90 pages so is fairly short. Subnetting is adding network components particularly routers and switches to a network where they use something something called a subnetwork mask which is a unique number identifying that device. Subnets come in different classes with class having potentially 16 million components and computers on a network. Organisations and companies who are huge and only use around 10,000 of these allocations will typically purchase one of these subnet classes. The Ministry of Defence in Britain is one such user of this class. Then there are classes B and C which correspondingly get smaller. Each of these steps of classes starts at 255 and goes down in increments of 32. Don’t make the mistake of halving or doubling them. Class D is multicast where one IP address is used for multiple broadcasting or receiving. Class E is used for experimental use. There is a subnet calculator available at http://howtonetwork.net. The more hosts on a subclass the fewer receiving units are each network. The higher the number of the subclass the fewer the number of hosts. Often the network components on a network seek an address automatically but sometimes if there are designated addresses you have to enter them manually. The latest standard is IVPV6 although sometimes IVPV4 is sometimes used. To work out these addresses the computer uses binary where a circuit being on corresponds to a 1 and off 0. This is rather complicated for humans so we tend to use octal or hexadecimal. They are base 8 and base 16. The binary blocks are normally grouped into blocks of 255 in decimal to make it possible to see at a glance. I thoroughly enjoyed this book and do recommend it.