IP addresses currently have 2 forms, an IP version 4 address which is a 4 octet dotted decimal number and a IPv6 which is significantly larger and harder to remember. Once upon a time IPv4 was thought to have so many addresses that we would never use them all, now we know better and IPv6 was introduced to fix the issues with the limited address space available through IPv4. Unfortunately IPv6 still isn't widely adopted and in use and most organizations still tend to use IPv4. Thus we have subnetting. Subnetting allows us to break the addresses available in the IPv4 space into segments so we only use what we need. This article explains this concept and how subnetting works.