IP addresses are a crucial part of how the internet works. Yet if you asked the average person you met on the street how IP addresses work, they’d probably have no idea. That’s because the role IP addresses play happens mostly behind the scenes, saving most internet users from ever having to worry about them one way or another.
But anyone who wants a better understanding of how the internet—that thing we all depend on every day—functions, understanding how IP addresses work is a big part of it. And anyone who works in IT or a number of other internet-dependent fields is likely to encounter the use of IP addresses in their work. Knowing how IP addresses work could help you do your job better.
Here’s a rundown of everything you need to know about how IP addresses work.
What Is an IP Address?
The IP in IP address stands for internet protocol. That term describes the set of rules or processes that determine how the internet works. In particular, it governs how data is sent over the internet from one device or network to another through a search engine.
The address part of the term is a little more straightforward. It’s the unique number used to identify every device and network that’s connected to the internet. Where your home address includes a street and a number, your IP address is usually made up of a string of numerals separated by periods. It’s easy to think of the IP address as your website’s destination for the traffic that’s coming to visit you.
To see an example, you can look up what the IP address for the network you’re currently on looks like using HostGator’s IP lookup tool.
For most of the people reading this, the IP address you see there will IPv4 (IP version 4), which means it’s four numbers, each between 0 and 255, divided by periods.
But because there’s a limited number of addresses you can generate in that format and the internet is growing at an explosive speed, some IP addresses are now formulated using IPv6 (IP version 6). IPv6 addresses include up to 32 digits, combine alphabetical and numerical digits, and have sections separated by colons rather than periods. They look like this: 2001:0db8:85a3:0000:0000:8a2e:0370:7334.
In order for a visitor to find your website and not your competitors, you will have to have a unique identifier number. That’s where IP addresses come in. These decimal numbers are what keeps your website connected to the web and allow other computers, mobile phones, and other devices to communicate with one another. .
How Do IP Addresses Work?
For the internet to work the way it does, different devices and networks all need a way to communicate with one another. While we, humans, give our devices names (think: Suzy’s iPhone or Joe’s Computer) and use domain names to access websites (e.g. www.hostgator.com), the machines we use to make those connections depend on IP addresses to identify each other.
Every device that connects to the internet is hardwired to include TCP/IP (Transmission Control Protocol/Internet Protocol), the communication system that dictates all the rules and processes by which devices are connected to the internet and share data with each other. That’s their language, and these unique identifier numbers are a part of how they understand and communicate with each other.
When a person uses their computer to access a website, the device needs a way to understand where that website is and pull up all the component parts it’s made of. To do that, the computer communicates with its network router, which then connects to the server the website lives on in order to access the files that make up the website.
Each device involved in this process—the computer, the router, the server—has a unique IP address that the other devices depend on to recognize it. The machines know which website to pull up and which computer to deliver it to based on those IP addresses
What Does An IP Address Tell You?
IPv4 addresses are made up of a couple of parts that each communicate something specific. The first part identifies your network, while the second part is for your specific device or host. If you look at the IP addresses for different devices connected to your home network, you’ll notice that they’ll have the first part of the IP address in common. That’s because they’re all connected to the same router and thus share a public IP (more on that later).
How much of the first part of the address is devoted to the network address isn’t consistent. That part has to do with the classes of IP addresses that were set up in the early days of the internet to designate between network sizes. For class A IP addresses, only the first section of the four is devoted to the network; for class B ones it’s the first two; and for class C addresses, it’s the first three.
Your computer network is programmed to recognize which part of an IP address is for the network, and which is for the host using something called subnet masks. The different IP classes and subnets come more into play when dealing with really large networks. For most home and business networks, none of these details make much of a discernible difference in what your IP addresses will look like or how they’ll work.
How Are IP Addresses Assigned?
At the highest level, IP addresses are assigned by the Internet Assigned Numbers Authority (IANA). The IANA allocates blocks of IP addresses to regional internet registries (RIR), who then divide those up between internet service providers, governmental organizations, schools, companies, and other institutions within their region.
For most home and business networks, you’ll be automatically assigned an IP address from the block of addresses the IANA allocated to your ISP. In most cases, they’ll provide you with a dynamic IP, meaning it won’t stay consistent. If you used HostGator’s IP tool above to see what your network’s IP address is right now, you may well find it’s something entirely different within a week.
ISPs opt for dynamic IP addresses because it’s easier for them. They don’t have to make a special point of reconfiguring a network’s address every time a customer changes their location. Dynamic IP addresses have the added benefit of making your network more secure. Hackers will have a harder time slipping into your network if your IP address changes frequently.
Private and Public IP Addresses
The IP address assigned to you by your ISP is your public IP address. That’s the one associated with your overall network. It’s sometimes described as your default gateway address, and it’s the address you’ll see associated with your router. Every network and device outside of your own network will recognize and track you via this IP address. It’s tied to all the internet activity that happens within your home or business.
In addition to your main public IP address, every device connected to your router will have a private IP address. As discussed previously, these private IP addresses will generally all resemble the public IP address in the first part of the construction, with the last section being what makes each unique.
For example, if the public IP address for your network is 220.127.116.11, your private IP addresses might include 18.104.22.168, 22.214.171.124, 126.96.36.199, etc. Having a private IP address for each device is important so your router can distinguish them from one another.
In addition to the most obvious devices you use the internet on, like your computer and phone, every device that connects to bluetooth or uses smart technology will also have a private IP. That includes any bluetooth headphones, smart TVs, wireless printers, and smart lights—just to name a few examples of the kind of devices you may have on your network.
Your router assigns each device a private IP automatically. You can also change the private IPs on most types of devices pretty easily if you so choose.
But generally, you won’t ever need to know or think about the private IP addresses on your network. The different devices will use their IP addresses to connect to and communicate with each other, but they’ll also have easier-to-remember names that either you created or that came supplied by the manufacturer (such as Suzy’s iPhone). Those will be what pops up in any situation you need to identify them.
What Is an IP Address Used for?
The general answer is that an IP address is used to identify a specific device, website, or network when other devices need to connect or communicate with it. When it comes to specifics, what an IP address is used for depends on the type of IP address.
Private IP addresses are used to differentiate devices on one server. A router needs to be able to tell the difference between your computer and a pair of bluetooth headphones. And your headphones need to be able to recognize the phone you pair them with. Every time those different devices communicate with one another, they do so by recognizing each other’s IP addresses.
Public IP addresses are used to identify a specific network. Even though they change regularly, your ISP is able to track the activities associated with your particular network based on your public IP address. This is how they’re able to identify and address instances of illegal online activity, such as downloading pirated material or sending spam emails.
The IP addresses of web servers are used to identify the websites stored on that server. They’re an important part of how your router and browser know how to recognize and pull up a specific website. For shared web hosting plans though, multiple websites will sometimes have the same IP address. In those cases, have no fear, your web hosting service provider will make sure each visitor is directed to the right website based on your domain name, which is what your visitors will be using to access the site anyway (only other machines use an IP address).
How DNS Servers Work
The domain name system (DNS) is an important part of how routers and browsers know how to translate domain names into IP addresses and vice versa. The DNS concept is often compared to a phone book—it’s the directory of which domain names are registered with which IP addresses. DNS servers are the technology that stores all those domain names and IP addresses and does the work of translating them for you.
Your router will be configured to work with a specific DNS server (or a couple), probably whichever ones your ISP defaults to using. It’s just one more step in the communication process across machines that keeps the internet working the way we all want and need it to. Your device sends a message to your router about what website you want to see via your browser, the router connects to the DNS server, which translates the domain you entered into an IP address, which connects you to the specific website you seek and—voila!—you see this web page.
And with internet and website speeds where they are for most consumers today, all of that happens within a split second. And notably all of it occurs in the background, where you don’t have to worry about it.
In Conclusion: What IP Addresses Mean for You
If you’re a casual internet user (or even a frequent internet user, like most people are today), how IP addresses work doesn’t mean anything significant for what your day-to-day browsing looks like. All of these systems of communication are set up to work seamlessly behind the scenes, while you go about using the more consumer-friendly interfaces and processes that have been set up for humans.
You can name your internet-connected devices with names that will be easy for you to remember and identify. And when you set up a website or go to visit one, you’ll use a domain name that’s intuitive and much easier to remember than a string of numbers. But for some people who do work on the more technical side of things, understanding how IP addresses work is an important part of keeping things running smoothly for the rest of us.
If you’re a HostGator customer and want to understand more about your website’s IP address, you can learn about how to find and use the IP addresses associated with your account here.
Kristen Hicks is an Austin-based freelance content writer and lifelong learner with an ongoing curiosity to learn new things. She uses that curiosity, combined with her experience as a freelance business owner, to write about subjects valuable to small business owners on the HostGator blog. You can find her on Twitter at @atxcopywriter.