IP addresses explained simply
In short: An IP address is a device's address on a network, like a house address for letters. Private addresses work inside your home or office; a public address identifies your connection on the internet.
The postal address comparison
To deliver a letter you need an address. To deliver data, a network needs an IP address (Internet Protocol address). Every device on a network gets one so information reaches the right place.
What an IPv4 address looks like
An IPv4 address is four numbers from 0 to 255, separated by dots, for example 192.168.1.25. Part of it identifies the network (like the street) and part identifies the device (like the house number). The subnet mask, such as 255.255.255.0, tells the device where that split is.
Private vs public addresses
| Private address | Public address | |
|---|---|---|
| Used | Inside homes and offices | On the internet |
| Unique? | Only within that network; millions of homes reuse the same ones | Unique worldwide |
| Ranges / example | 10.x.x.x, 172.16.x.x to 172.31.x.x, 192.168.x.x | Given to you by your internet provider |
Your router uses NAT to let all your private devices share one public address.
Special addresses worth knowing
127.0.0.1: "this computer" (loopback), used for testing.169.254.x.x: the device couldn't get an address automatically. Usually a DHCP problem.- The default gateway is your router's address, the "exit door" to other networks.
Why IPv6?
IPv4 has about 4.3 billion addresses, which isn't enough for every phone, laptop and smart device on Earth. IPv6 uses much longer addresses written in hexadecimal, like 2001:db8::1, giving a practically unlimited supply. Most networks now run both.
Find your own IP address
Windows: ipconfig
macOS / Linux: ip addr (or ifconfig)Ready for more? Learn to split networks in Subnetting in your head, or try the subnet calculator.
Real-world example: your laptop moves from home to a café
At home, your laptop might have the address 192.168.1.25. You take it to a café and join their Wi-Fi. Within seconds it has a different address, perhaps 10.0.0.57, because it is now living on a different "street". Nothing was typed by hand: the café's router gave it an address that fits its own network.
Here is the surprising part. A customer at the next table may have 192.168.1.25 on their own home network too. That causes no clash, because private addresses only need to be unique inside one network. On the internet, everyone in the café appears to come from the café's single public address, which belongs to its internet connection.
Try this: run ipconfig (Windows) or ip addr (Linux) at home, then again on another Wi-Fi network. Compare the addresses and the default gateway. Then search the web for "what is my IP" and notice the public address is completely different from the private one.
Key takeaways
- An IP address is a device's address on a network.
- Private addresses are reused inside networks; public addresses are unique on the internet.
- 169.254.x.x means automatic addressing failed.
- IPv6 exists because IPv4 addresses ran out.
Original content written by Mohamed Fayas for FM TecHub. © 2026 FM TecHub. You're welcome to share a link to this page; please don't copy the text elsewhere without permission.