What's an IP Address, and What Is My IP Address?

Most of us know two things about IP addresses: they seem to be important and they are definitely complicated. That’s a good start, but cord-cutters that are interested in home networks or internet privacy and security should have at least a basic knowledge of IP addresses.

Let’s dive right in, with answers to some intro questions like — what’s an IP address, what’s your IP address, and where do IP addresses come from?

Computers on the internet need a way to recognize one another. Just like a mailing address uniquely identifies your home in the real world, an internet protocol (IP) address uniquely identifies your computer in the digital world.

Unlike your mailing address, though, IP addresses aren’t really made for human usage. Instead of easy names like Main Street, IPs use long strings of seemingly random numbers or even numbers and letters. As we’ll discuss later, these aren’t truly random, but they definitely aren’t made for humans to remember.

IP addresses are built for computers to use when talking to each other. Every action on the internet — from accessing a website to sending an email — requires that packets of information be sent back and forth between computers. These packets are crucial parts of how the internet works, and the entire system would fail if packets couldn’t find their destinations. That’s where IP addresses come in.

What Information Is in an IP Address?

IP addresses carry information about both your location and the internet service provider (ISP) that you use. This is a good chance to point out that — unless you use a VPN — any website or app that you are interacting with can see your IP and use it to determine your location. The actual precision that they can see might vary, but it’s safe to assume that your IP address at least gives away your city, if not your postal code.

You actually have two IP addresses. Before you go bragging to your friends, I should clarify: everyone has both a public and a private IP address.

Every network is assigned only a single public IP address. That means that whether you have a single device in your home or 30, they all have the same public IP. To continue with our mailing address analogy, this would be just like you and your housemates all sharing the same mailing address. And just like how all your mail goes to the same mailbox, all the internet traffic for your devices goes to the same router — the device that accepts and sorts all messages coming into or leaving your home network.

Your router assigns a second address — your private IP — to keep track of everything inside your network. When packets come into your network, the router sorts them and sends them to the appropriate computer based on the private IP. This is loosely equivalent to the way that one of your housemates gets all of the mail from your mailbox and delivers it to each of you based on the name on the envelope.

Finding Your External IP

Because the external IP is known to the world, it’s very easy to check. There are several websites that will let you know your external IP address for free, including WhatIsMyIPAddress.com.

You might see two IP addresses, one that says IPv4 and one that says IPv6. I’ll explain the difference between those a bit later. For now, know that they both serve the same basic purpose. Alongside the IP address, you’ll typically see location information and the name of your ISP, all of which is derived from your external IP.

Finding Your Internal IP

Your internal IP address is a bit harder to locate because only your computer and your router know what it is. For this reason, the process will depend on what type of computer you are using.

Windows

1. Open the command prompt by typing “cmd” into your system search bar and hitting enter or selecting the item that says Command Prompt.
2. In the command prompt window, type “ipconfig” and hit enter.
3. You’ll see a lot of data pop up. Look for a section that says Wireless LAN adapter Wi-Fi if you are on Wi-Fi or one that says Ethernet adapter if you are on a wired connection.
4. In that section, you’ll see a row that says IPv4 Address and one that says IPv6 Address. One or both of these should have your internal IP address.

macOS

1. Open System Preferences from the dock or by using the search button in the system menu bar.
2. Select the icon that says Network.
3. Your IP address is on that screen, but you may not immediately see it. It’s in the text paragraph under the Status section.

Android

The steps for finding your internal IP on Android may vary based on your OS version, but these steps will work on most versions.

1. Open your Settings menu.
2. Select the About Phone option.
3. Click the Status section.
4. You’ll see your internal IP under the section that says IP Address.

iPhone/iPad

1. Open Settings.
2. Select the Wi-Fi section.
3. Under your current network, click the button that looks like an i in a blue circle.
4. You’ll find your internal IP under either or both of the IPV4 ADDRESS or IPV6 ADDRESS sections.

The Internet Assigned Numbers Authority (IANA), a division of the Internet Corporation for Assigned Names and Numbers (ICANN) is in charge of allocating IP addresses. ICANN is an international nonprofit that is heavily involved in managing the internet and ensuring that it runs securely and fairly.

IANA doesn’t directly assign your computer an IP address. Instead, they assign large blocks of IP addresses to Regional Internet Registries (RIRs), which in turn hand them down to National Internet Registries (NIRs). At the bottom of that pile of acronyms, the IP addresses are given to ISPs who assign individual addresses to each of their subscribers (that’s you!). This hierarchical model is the reason why there is so much location information in your IP address.

Dynamic vs. Static IP Addresses

In most cases, ISPs assign what are known as dynamic IP addresses. As the name implies, dynamic IPs can and do change over time, whereas Static IPs never change. You can only acquire a static IP by paying an extra charge to your ISP. Static IPs are ideal for app servers and other computers that need to have a consistent “location” over time, but dynamic IPs are fine for most internet users.

ISPs have a few reasons for preferring dynamic IPs, but the biggest reason is cost savings. ISPs pay money for their blocks of IP addresses, and they pay more for larger blocks. With static IPs, they would need one IP address for each customer. But not every user is online 24/7, so dynamic IPs allow them to purchase fewer IPs than they have customers. When you go off-line, your IP can be reassigned to someone else. Whenever you log back in, they just pick an unused IP and send it your way.

Dynamic IPs are more secure for you as the end user. IPs are one of the best tools that advertisers and other tracking services can use to follow you around the internet. When your IP address changes, they lose the ability to easily track you. If you had a static IP, they only have to find you once and you’d never be anonymous online again.

Public IPs aren’t the only ones that can be static or dynamic — your private IP can be, too. You don’t even need to pay extra for static private IPs. If you want to change back and forth between dynamic and static private IPs, you can do so in your computer’s network settings.

Dynamic public IP addresses will change eventually, but there’s no guarantee that it will happen quickly. Resetting your router increases the likelihood that your IP address will change, but it doesn’t guarantee a change. Some ISPs are willing to change your IP address by request, so you can try contacting them if you need a new IP address for any reason. ISPs will also typically let you change a static IP, but the entire point of having a static IP is to avoid that scenario.

The best way to change your IP quickly is to use a VPN. When you are running a VPN, other computers on the internet will see the VPN server IP address instead of yours. This makes it difficult for them to track you through your IP, and VPNs mask the ISP and location information that your IP address typically gives away. By switching VPN servers, you can change your IP as frequently as you want to.

We’re going to dive into something a bit more technical for a moment here, so feel free to skip this section. You won’t miss anything important to a general understanding of the internet.

If you’ve seen any IP addresses, they probably looked something like this: 10.10.1.101, with four sets of numbers separated by periods. But you may have also noticed some that look much more complicated, like this: 2001:0db8:85a3:0000:0000:8a2e:0370:7334, with eight sets of both letters and numbers separated by colons. These are both IP addresses, but there’s a huge difference between them that illustrates how much the internet has changed in just a few short decades.

The shorter, entirely numeric addresses are IP version 4 (IPv4). From their launch in 1980, these were the standard addresses used across the entire internet. That worked great for several years, but IPv4 had a fatal flaw: it only allowed for about four billion devices. Back then, that seemed like plenty. After all, there were only four billion people on Earth, most countries didn’t have internet access, and most people in the developed world had either zero or one device.

Okay, so foresight wasn’t their strong suit.

Now, there are nearly eight billion people, the internet is rapidly expanding into every country on the planet, and the average American household has 11 internet-connected devices. Needless to say, four billion devices simply isn’t enough. That’s why IPv6 — that much longer alphanumeric address system — was released in 2012.

This time, they weren’t messing around. The old system had 4 billion addresses, so would you like to guess how many the new system has? If you guessed 340 undecillion — 340 trillion trillion trillion — you are right. That’s 340 followed by 36 zeros! Each person on the planet could have 47 octillion devices, and there would still be addresses left over. If those numbers sound too big to comprehend, that’s exactly the point.

Expect to see these longer addresses become more common in the future. For now, though, you’ll run into mostly IPv4 addresses in most of what you do, so don’t worry if this section and its giant numbers were a bit overwhelming — just think of this as a fun little bit of internet history that you can share with your friends.

IP addresses play a key part in making the internet work. In fact, they are a crucial aspect of all network infrastructure. As such, a basic knowledge of IPs is important for all cord-cutters. With your newfound understanding of IPs, you are better equipped to handle issues with your Wi-Fi network or to set up your own VPN.

Then again, maybe it’s time to take a break from learning and relax with a movie binge. If IP addresses weren’t terrifying enough, you could always try out the horror movies over at the Shudder streaming service.