What Is an IP Address?

Definition of IP address and why all computers and devices need one

An IP address, short for Internet Protocol address, is an identifying number for network hardware connected to a network. Having an IP address allows a device to communicate with other devices over an IP-based network like the internet.

What Does an IP Address Look Like?

Most IP addresses look like this:

151.101.65.121

Other IP addresses you may come across could look more like this:

2001:4860:4860::8844

What Is an IP Address Used For?

An IP address provides an identity to a networked device on the internet. Similar to a home or business address that supplies a specific physical location with an identifiable address, devices on a network are differentiated from one another through IP addresses.

If you send a package to a friend in another country, you have to know the exact destination. This same general process is used to send data over the internet. However, instead of using a physical mailing address, the computer uses DNS servers to look up a hostname to find its IP address.

For example, when you enter a website URL such as www.lifewire.com into a browser, your request to load that page is sent to DNS servers that look up the hostname of lifewire.com to find its corresponding IP address. Without the IP address, the computer has no clue what it is that you're after.

IP Versions (IPv4 vs IPv6)

There are two versions of IP: internet protocol version 4 (IPv4) and internet protocol version 6 (IPv6). The former is the older version, while IPv6 is the upgraded IP version.

One reason IPv6 is replacing IPv4 is that it provides a larger number of IP addresses than IPv4. When multiple devices on the same network are connected to the internet, it's important that there's a unique address available for each device.

  • IPv4: The way IPv4 addresses are constructed means it's able to provide over 4 billion unique IP addresses (232). While this is a large number of addresses, it's not enough for the modern world with all the different devices used on the internet.
  • IPv6: IPv6 supports 340 trillion, trillion, trillion addresses (2128). That's 340 with 12 zeros! This means every person on earth could connect billions of devices to the internet.

Visualizing this helps understand just how many more IP addresses the IPv6 addressing scheme allows over IPv4. Pretend a postage stamp could provide enough space to hold each and every IPv4 address. IPv6, then, to scale, would need the entire solar system to contain all of its addresses.

Image of a solar system.
Mensent Photography / Getty Images

In addition to the greater supply of IP addresses over IPv4, IPv6 has the following added benefits:

  • No IP address collisions caused by private addresses
  • Auto-configuration
  • No reason for Network Address Translation (NAT)
  • Efficient routing
  • Easier administration
  • Built-in privacy

IPv4 displays addresses as a 32-bit numerical number written in decimal format, for example, 207.241.148.80 or 192.168.1.1. Because there are trillions of possible IPv6 addresses, they must be written in hexadecimal to display them, for example, 3ffe:1900:4545:3:200:f8ff:fe21:67cf.

Different Types of IP Addresses

There are specific types of IP addresses. While all IP addresses are made up of numbers or letters, not all addresses are used for the same purpose. There are private IP addresses, public IP addresses, static IP addresses, and dynamic IP addresses.

Each type of IP address can be an IPv4 address or an IPv6 address.

  • Private IP Address: These are used inside a network, for example, a home network that is used by tablets, Wi-Fi cameras, wireless printers, and desktop PCs. These types of IP addresses provide a way for devices to communicate with a router and the other devices on the private home network. Private IP addresses can be set manually or assigned automatically by the router.
  • Public IP Address: These are used on the outside of a network and are assigned by an ISP. It's the main address that a home or business network uses to communicate with the rest of the networked devices around the world (for example, the internet). It provides a way for the devices in a home, for example, to reach an ISP, and therefore the outside world, allowing the devices to access websites and communicate directly with other computers and servers around the world.

Both private IP addresses and public IP addresses are either dynamic or static, which means that, respectively, they either change or they don't.

An IP address that is assigned by a DHCP server is a dynamic IP address. If a device doesn't have DHCP enabled or doesn't support DHCP, then the IP address must be assigned manually, in which case it's called a static IP address.

What Is My IP Address?

Different devices and operating systems require unique steps to find the IP address. There are also different steps to take if you want to know the public IP address provided to you by your ISP, or if you need to see the private IP address that the router assigned to a device.

How to Find a Public IP Address

There are several ways to find a router's public IP address, but sites like IP Chicken, WhatsMyIP.org, WhatIsMyIPAddress.com, or icanhazip.com make this easy. These sites work on any network-connected device (such as a smartphone, iPod, laptop, desktop, or tablet) that supports a web browser.

IP address shown in Google

How to Find a Private IP Address

Command Prompt ipconfig results in Windows 10

Learn how to find the default gateway IP address if you need to find the IP address of your router, or whatever device that your network uses to access the public internet.

To find a private IP address on other operating systems:

  • Linux: For Linux, launch a terminal window and enter the command hostname -I (that's a capital "i"), ifconfig, or ip addr show.
  • MacOS: For macOS, use the command ifconfig to find the local IP address.
  • iOS: iPhone, iPad, and iPod touch devices show their private IP address through the Settings app in the Wi-Fi menu. To see it, tap the small "i" button next to the network it's connected to.
  • Android: Find the local IP address of an Android device through Settings > Network & internet > Wi-Fi, or depending on your Android version, Settings > Wi-Fi or Settings > Wireless Controls > Wi-Fi settings. Tap the network you're on to see a new window that shows network information that includes the private IP address. Expand the Advanced area of the network details page to see the private IP address.