How to Find Your Private and Public IP Addresses

Each device on your network has a private IP address only seen by other devices on the local network. But your ISP assigns you a public IP address that other devices on the Internet can see. Here’s how that works and how you can find those IP addresses.

An IP address (or Internet Protocol address) identifies each networked computer and device on a network. When you sign up with Internet service and connect your modem, your ISP assigns you a public IP address. This address is how you communicate with all the other devices out there on the public Internet. But, you’ve likely got multiple computers and other devices on your network—each of which needs its own IP address. So, how does that all work and how can you find out what all those IP addresses are? Read on for the answer!

Public vs. Private IP Addresses

The answer to all this IP address wizardry is that your router—whether it’s a standalone device or a modem/router combo unit—essentially serves as a bridge between two networks. In a typical home network, a router has a public IP address on the Internet. The computers, smartphones, game consoles, and other devices behind the router each have a unique private IP address on the home network. The router acts as an intermediary, forwarding traffic to the local IP addresses that request it. From an outside perspective, all devices on the home network are communicating with the Internet from a single public IP address.

Note that if your computer is connected directly to the Internet with no router sitting in between—something we really don’t recommend—your computer’s IP address is a public IP address.

Sometimes, you might need to know the private IP address of a device or your network’s public IP address—or maybe both. Here’s an example. Say you’re hosting some kind of server software on a computer on your network and you need people on the Internet to be able to connect to it. Maybe you’re playing a multiplayer game, maybe you need to access a home-hosted media server, or maybe you just want to get remote access to one of your PCs.

You’ll need to know your network’s public IP address that people can type into their client software. And you’ll need to know that computer’s private IP address so you can configure your router to direct that kind of traffic to the right computer on your local network.

Your computer likely has public and private IP addresses. You’ll need the IP address if you’re hosting server software – the client computers will need your computer’s IP address to connect to it.

Finding Your Private IP Address

It’s not difficult to find a device’s private IP address. In fact, we’ve got a great guide that shows you how to find your IP address on almost every platform out there, so we recommend you take a look at that for specifics on how to find the private IP address of your particular device. In short, though, you usually need to check out the network settings on your device and look for any information labeled “TCP/IP,” “IP Address,” or just “WiFi.”

On most full computing platforms—like Windows, MacOS, and Linux—you can often find the information quickly using the Command Prompt or Terminal. For example, in Windows, you can open the Start menu, search for Command Prompt, and press Enter. Then type ipconfig in the Command Prompt that appears and press Enter—you’ll get to what you’re looking for in no time.

Finding Your Public IP Address

The easiest way to find your public IP address is by asking a website, since that website sees your public IP address and can tell it to you. We recommend using the site ip4.me because it’s quick, ad-free, and will show your IPv4 address—the four part address you’re most likely looking for—rather than the more complicated IPv6 address that your network is likely also configured to use. Just visit the site and it will show you your public IP address.

You can also access your router’s administration page to find this information. This page displays your public IP address and other information about your Internet connection. Different routers have different administration page layouts and different default local IP addresses. Consult your router’s manual or the manufacturer’s website if you need more information. And if you need it, we also have a good guide on finding your router’s IP address.

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You should also know that unlike street addresses, IP addresses aren’t necessarily fixed. Unless you’ve purchased a static address from them, your ISP may occasionally assign you a new public IP address. And, unless you’ve configured static IP address assignments for your local devices, your router may occasionally assign your devices new IP addresses.

Chris Hoffman is a technology writer and all-around computer geek. He's as at home using the Linux terminal as he is digging into the Windows registry. Connect with him on Google+.

  • Published 06/24/12
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