Did you know that every device that’s connected to the internet uses something called an IP address?
IP stands for internet protocol and it’s a sequence of numbers which acts as a unique identification code. Think of it like a phone number which lets computers communicate with each other. Here we explain how IP addresses work and how you can discover yours.
What is an IP address?
A standard IP address (which is known as the IPv4 protocol) consists of four sets of up to three digits, usually represented as XXX.XXX.XXX.XXX. Everything that’s connected to the internet has an IP address and, since they run on computers that are also connected to the internet, websites have one, too.
Try entering ‘18.104.22.168’ into your web browser’s address bar to see where it takes you.
How do I find a website’s IP address?
Web addresses aren’t what you think they are – URLs such as bt.com are only there for our benefit as they’re easy to remember, but actually these web addresses correspond to an IP address as well.
So when you type bt.com, behind the scenes it’s actually going to 22.214.171.124. This is thanks to something called the Domain Name System, or ‘DNS’, which translates IP addresses into character-based URLs.
You can find the IP address of any web site using Windows’ Command Prompt. Search for “command prompt” on a PC. When the Command Prompt window opens, type ping the web address, for example: ping bt.com and press the Return key. The IP address of the web address you used will then be displayed.
What is your computer’s IP address?
Your computer’s IP address is assigned by your ISP and you can find out what it is by visiting www.whatismyip.com. The site will also show which city and country you’re in, and the name of your ISP. IP addresses are allocated on a per-country basis and ISPs then allocate them to customers based on geographical location.
This information can all be gleaned from an IP address, so don't be alarmed if a web site appears to know your whereabouts.
IP addresses and home networks
The IP address shown by www.whatismyip.com is that of the device connected directly to your internet connection and, in most cases, this is a home router. ISPs only assign one IP address to each customer, but when several devices are connected to the same router, each also needs its own IP address to distinguish it online. Routers get around this problem using something called network address translation, or NAT.
In simple terms, a router assigns its own internal IP address to every device that’s connected to it, usually of the form 192.168.XXX.XXX. The router then keeps track of these internal addresses when they communicate with the internet to ensure that the correct web page, for example, is delivered to the device that originally requested it. You can see your router’s NAT settings (sometime referred to as DHCP, or Dynamic Host Configuration Protocol) in its settings.
Find an internal IP address
If you’re having problems getting a computer online at home, establishing its internal IP address (or lack of) will tell you if it’s successfully connected to your network. Open a Command Prompt by searching on your PC, type ipconfig /all and press Return.
A long list of information will appear - look for the line “IPv4 Address” to find the internal IP address assigned by your router. If there isn’t one, or if it doesn’t begin with “192.168.”, then the computer isn’t connected to your network.