What Is the Difference Between IPv4 and IPv6?

Every device on the internet needs an address so data knows where to go. That’s an IP address. For years most of the internet ran on IPv4, and it’s still all over the place. The trouble is there just aren’t enough IPv4 addresses for a world full of phones, laptops, smart TVs, and random gadgets.

IPv6 showed up to fix that. The names sound like version one and version two of the same thing, but it’s a bigger change than adding a number.

IPv4 Ran Out of Room

IPv4 uses 32 bit addresses, written as four numbers with dots between them, like 192.168.1.10. Each chunk goes from 0 to 255. That adds up to about 4.3 billion addresses, which sounds like plenty until you count how many devices one household owns.

So networks started using NAT, which lets a bunch of devices share a single public address. It works, and it’s worked well for a long time. It just puts one more layer between your device and the rest of the internet.

IPv6 Goes Way Bigger

IPv6 uses 128 bit addresses, written in hexadecimal with colons, something like 2001:db8:85a3::8a2e:370:7334. The number of possible addresses is silly big. Every device can have its own, and nobody has to worry about running out. That’s really the whole reason it exists. The internet outgrew its original addressing system.

If you’ve only ever seen IPv4, an IPv6 address looks kind of ridiculous at first. You get used to it. Long strings of zeros can be shortened too, which is why you’ll see those double colons. IPv6 can also configure addresses automatically, which makes life easier on big networks.

What About Security?

People get this one wrong a lot. IPv6 was designed with IPsec support, which helps authenticate and protect traffic. But switching to IPv6 doesn’t make you secure on its own. Firewalls, decent passwords, and sensible settings still matter just as much.

Why Is IPv4 Still Around?

Because changing the internet is messy. IPv4 has been running for decades, and companies built huge systems around it. Routers, apps, and admin tools all have to support the switch, so IPv6 hasn’t replaced anything overnight.

Both Live Side by Side

Plenty of networks run both at once, which people call dual stack. Your device just uses whichever one works for that connection. When you’re browsing you’d never notice. You type an address, the page loads, and that’s it.

You probably use both every day without knowing. Two very different addressing systems are quietly sharing the same internet under everything you do.