How Computers Work · Your Computer on a Network · Lesson 1 of 5

IP Addresses at Home

Find your computer's address, your router's address and your MAC address.

Finding your computer's addresses

A network is a group of devices that can talk to each other. Your home network might hold a laptop, two phones, a TV and a printer.

To send anything, each device needs an address. An IP address is a number that tells other devices where to send data. It often looks like four numbers with dots, such as 192.168.1.42. This style is called IPv4. You may also see a much longer kind called IPv6. It does the same job.

Your router is the box that links your home devices to the internet. It has an address too. Windows calls it the default gateway, because it's the door out of your home network. At home it often ends in .1, like 192.168.1.1.

Here is how to find these on Windows 11:

1. Open Settings and choose Network & internet.
2. Choose Wi-Fi (or Ethernet), then your network's properties.
3. Look for IPv4 address and IPv4 DNS servers.

There is also a quick way. A terminal is a window where you type commands. Open one, type ipconfig and press Enter. It lists your IPv4 address and default gateway.

On a Mac, open System Settings > Network, choose Wi-Fi, then Details. The TCP/IP tab shows your IP address and router.

Looking at these screens is safe. You are only reading, not changing anything.

On the practice computer, open the network properties and find your IPv4 address, the router's address and the DNS server. Then visit the "what's my IP" site and compare the two addresses.

Private, public and MAC addresses

In the lab, the "what's my IP" site showed a different address from the one in Settings. That's normal. Your computer really has two kinds of address at once.

A private address (or local address) only works inside your home network. Your router hands these out. They usually start with 192.168, 10, or 172.16 to 172.31. Millions of homes use the same private numbers, and that's fine, because they never leave the house.

A public address is the one the rest of the internet sees. Your internet company gives it to your router. Every device in your home shares it when going online.

Think of an apartment building. The building has one street address (public). Each apartment has its own number inside (private). The router is the front desk that sorts the mail.

There is one more address. A MAC address is a fixed ID built into your computer's network hardware, written like 3C:52:82:1A:9F:04. It's used inside your local network, not across the internet. Windows lists it as the Physical address (MAC). On a Mac, it's on the Hardware tab in the same Details window.

Many phones and computers can now use a random MAC address for each Wi-Fi network, to make tracking harder. You may have seen this setting in the Mobile lessons. Phones work the same way.

A few quick facts help later:

• Your private address can change from day to day. That's normal.
• Your public address can change too, when your internet company decides.
• An address starting with 169.254 means your computer couldn't get a proper address from the router.