Any computer or device that wants to communicate with the Internet Protocol needs an IP address to uniquely identify the device.
And some devices could have multiple IP addresses. There needs to be at least one IP address for each network card or interface that the computer or device uses to connect. For example, you could have a single computer with three network cards, two wired, and one wireless. Each one of these would need at least one IP address and could have more.
This episode will explain two types of IP addresses, version 4 and version 6. I’m not sure what happened to versions 1, 2, 3, or 5. Version 4 has been in use since the beginning of the internet and version 6 is struggling to gain acceptance. Normally, version 4 is called IPv4 and version 6 is called IPv6. We’re going to have to all move to version 6 eventually just because we’re running out of version 4 addresses.
The biggest problem with IPv4 addresses is there are so few of them. You might think that 4 billion addresses are a lot and that’s just what the early designers thought too. That’s just not enough for every computer in the world to have it’s own address though.
We’ve managed to stretch IPv4 addresses a lot over the years. While researching this episode, I checked on the current state of IP addresses remaining that haven’t been assigned yet. You might still be able to get some IPv4 addresses in Africa but the rest of the world is already out of luck.
We no longer divide addresses into class A, B, or C ranges because the size differences between the ranges is just too much that it led to a lot of addresses being wasted. Imagine it like this. Let’s say that the grocery store only sells eggs in containers of ten, a hundred, or a thousand eggs. If you need to make an omelet with 15 eggs and can only purchase one container, then you have no choice but to buy a hundred. Maybe you can use the other 85 eggs but you’ll probably waste a few.
Another method that’s been used very well to extend addresses has been to stop assigning public IP addresses to each computer in a company or in your home. It’s these public IP addresses that we’re running out of. It’s more common for a computer to look for a service called the Dynamic Host Configuration Protocol or DHCP for short. This is a service that can run on a router or even on a dedicated computer. When your computer joins a network, then it can look for this service and ask it for an IP address. This address is temporary and can change if the computer is restarted.
Listen to the full episode for more ways that we’ve managed to extend the usefulness of IPv4 and how IPv6 can help.