The 4 Parts of IPv4 IP Addressing

Most likely, you’ve already checked your IP address at WhatIsMyIPAddress.com a few times. Usually you’re just checking to see if it’s changed or not. Your IP address at home will be different from the IP address at your work office. And that IP address will be different from the one you would have if you used the free wireless hotspot at a coffee shop or hotel. But they all have one thing in common: They will be in four sections, separated by three periods or dots. That is the common structure for all IPv4 addresses (v4 stands for “version 4”). Have you ever wondered what those four sections represent? Here’s a quick overview: There will be some technical terms, but they’re nothing to be worried about. You will still be able to understand the basics of what’s going on with your IP address. At the heart of everything to do with computers is this fact: Computers have a language and method all their own. Everything you see on your screen has a format that your computer understands and translates into words numbers and pictures. Computers turn everything into numbers that are a combination of zeroes and ones. If a computer sees the decimal number (a number you recognize) 2,530, it turns that number into a longer string made up of only zeros and ones—0000100111100010. That’s called a binary number. Aren’t you glad your computer doesn’t talk to you in binary code? Computers calculate everything using the binary system. Every IP address is made up of 32 bits. Here’s an illustration of what that means: Let’s take the IP address 76.240.249.145. My computer—and all of the networking hardware and software—sees it as a 32-bit address in binary form that is subdivided into four 8-bit parts, called “octets.” Or you can simply see it in four parts: part1.part2.part3.part4. How the parts come together to define the IP address’s network ID and host ID also determines what Class of network that IP address is associated with. From now on, whenever you see your IP address, you’ll know that each section is actually an octet that’s part of a 32-bit number. This understanding becomes even more relevant given the IPv4 shortage , which is driving the transition to IPv6 for more extensive and secure internet connectivity. Just don’t bother sharing that knowledge with anyone—it won’t interest anybody who isn’t in the IT department.