IP addresses and networks
IPs are pretty simple overall, but where things get kind of complicated is their relationship to networks. When we covered the internet, we saw that computers are networked together through wireless signals and cables: but the world isn’t just one giant network, in the same sense that the world isn’t one giant town. It’s made up of tons of little local area networks (LANs), and the easiest example to walk through is your house or apartment.
When you sign up for WiFi, your internet service provider (Verizon, Spectrum, you know, our favorite brands) runs a cable into your crib. That cable connects you to the ISP’s giant network of all of the places they provide internet to (and their data centers). But you connect a router to that cable to generate wireless, and that actually creates a mini, local network for your apartment (a LAN). It kind of looks like this:
Here’s where things get tricky: your computer’s IP address is dependent on which network it’s in. When your laptop is at home, your local network will assign it some IP address – but if you head over to a coffee shop, that’s a completely different network, and you’ll probably receive a different IP address. In addition to that, sometimes your ISP will change your LAN’s IP address randomly. Moral of the story: your computer’s IP is dynamic (it works through a protocol called DHCP).
Networking is notoriously difficult and complex. If you’re unsure about WANs and LANs and the like, don’t worry: just try to think of it like a city vs. a state. Your address is unique within your local area, but not within the broader one.
All of that being said, there are some IP addresses that actually are universally unique. These are mostly called Class A, and there’s a whole hierarchy of different IP address classes.
Actual IP addresses
The mechanics of exactly how IP addresses work are beyond the fray, but here are a few simple, useful details that might help.
IPv4 and IPv6
There are actually two different types of IP addresses: short ones and longer ones. IPv4, the original and shorter format, is 32 bit and has four separate dots: you’re probably used to something like 192.168.1.102. IPv4 is kind of like the good old days of Twitter or Gmail when all of the good usernames were still available. As the internet kept growing and adding more networked computers, we started to run out of these. IPv6 is 128 bit, so it has six separate dots and allows for a lot more possible IP addresses. Maybe one day we’ll hit IPv8 or something.
Actual IP addresses to know
If you’ve ever tried troubleshooting your WiFi connection issues, there are a few common IPs you might recognize:
- 0.0.0.0 – the default network (no computers will have this)
- 255.255.255.255 – represents all computers on the network (if you need to send a message to everyone)
- 127.0.0.1 – the “loopback address” or your computer’s method for identifying itself
Otherwise, things are pretty much all over the place. If you ever need to figure out what your computer’s IP address is at any given point in time, you can use whatismyipaddress.com.
Who the hell is ICANN?
If you’re wondering how all of this IP stuff gets managed and allocated, you’re in good company (I’ve always imagined some reserved undertaker with dark eyelids, but that’s neither here nor there). There’s a non-profit organization called ICANN that takes care of a lot of the logistics, and they’re based in Los Angeles.
ICANN doesn’t only take care of IP addresses: they also manage the infrastructure for our DNS, or domain name system. We’ll cover domains and how they relate to IP addresses in another post.
##Terms and concepts covered
IP address
Local area network (LAN)
DHCP
IPv4, IPv6
ICANN
Further reading
- If you spin up a virtual machine on a cloud, the IP address changes all the time: you can provision a floating IP that stays the same all the time
- Firewalls let you control which IP addresses can communicate with your computer, and which get blocked
- In addition to ICANN, there’s an Internet Engineering Task Force that worries about these kinds of internet standards