What Is an IP Address? IPv4, IPv6, Public and Private, Explained in One Pass
A plain-language explanation of what IP addresses do, how IPv4 and IPv6 differ, how to tell public from private IPs, and why the IP you see isn't the one others see.
Mention "looking up an IP" and many people picture a hacker tracing a target in a movie. The concept is far more humble: an IP address is your house number on the network. This article explains it thoroughly.
What Problem Does an IP Address Actually Solve
Every device on a network talks to the others through packet switching: data is chopped into small packets, and each packet is labeled "from where, to where." That "to where" is the destination device's IP address.
Without an IP address, it's like mailing a letter with no recipient address — routers have no idea where to forward the packets.
IPv4: The 32-Bit Old World
An IPv4 address looks like 203.0.113.7 — four numbers, each from 0 to 255.
There are only about 4.3 billion addresses in total. When it was designed in the 1970s, nobody imagined every person on Earth carrying several connected devices, so around 2011 the IPv4 pool was fully allocated — which is why carriers turned to "shared IPs" and NAT.
IPv6: The 128-Bit New World
IPv6 looks like 240e:3b1:3000::1a2b — eight groups of hexadecimal digits.
The total is 2 to the 128th power — enough to "give every grain of sand on Earth its own address with plenty to spare." Mobile data traffic in China has been on IPv6 at scale for years — open the IPchase homepage on mobile data and you'll most likely see an IPv6 address starting with 240e or 2408.
The two versions will coexist for a long time; your device usually holds both an IPv4 and an IPv6 address at once.
Public vs. Private IPs: Why Your Lookup Differs From What the Router Shows
This is the most common confusion. Start by memorizing the three private address ranges:
| Range | Covers | Typical use |
|---|---|---|
10.0.0.0/8 |
10.x.x.x | Corporate networks |
172.16.0.0/12 |
172.16–31.x.x | Some companies, Docker |
192.168.0.0/16 |
192.168.x.x | Home routers |
The 192.168.1.100 your home router assigns your computer is a private address. There are millions of "192.168.1.100"s around the world; it only means something inside your home network.
The real public IP is what the carrier assigns to your broadband line. When data comes back from a website, it first reaches the public IP, then your router forwards it to the right device on the internal network (that process is NAT).
So: what you see in your machine's "network settings" is the private IP; what IPchase detects is the public exit you actually present to the world.
Dedicated Public IPs Are Getting Scarcer
One consequence: many mobile data users sit behind carrier-grade NAT, with hundreds of users sharing one public IP. That's fine for everyday browsing, but it blocks self-hosting from home or reaching your NAS remotely — and it's a direct driver of IPv6 adoption: with enough IPv6 addresses, every device can have a globally unique one.
When Others See a Different IP
Different devices on the same network showing the same IP (a shared exit) is normal. But if you're behind a proxy and the IP you look up doesn't match expectations, be careful — a DNS leak or WebRTC leak may be exposing your real exit.
- To verify: run a full check with the IPchase fingerprint test
- For the full mechanics, read this article: DNS Leaks Explained
Summary
- An IP address is your network house number — packets find you by it
- IPv4 has run out, IPv6 is taking over, and the two coexist
192.168.x.x/10.x.x.xare private addresses; to find your public IP you need an external service- What mobile data users look up is the carrier's exit, possibly shared by hundreds of people
Want to see your current public IP and its geolocation? Open the IPchase homepage — results in one second.
Check your own network: run a full disguise check on the homepage, or try the fingerprint test.