IPv4 ran out, IPv6 arrived: two address universes
2 min read
The difference between IPv4 and IPv6, how address exhaustion created CGNAT, and how to tell which one you are on.
The problem: 4.3 billion addresses were not enough
IPv4 (like 192.0.2.1) is a 1980s design carrying ~4.3 billion addresses; the internet outgrew that long ago and fresh IPv4 blocks officially ran out in 2019. IPv6 (like 2001:db8::1) solves it at the root: a practically inexhaustible space, a real public address for every device.
The everyday consequence of exhaustion: ISPs share one IPv4 among hundreds of subscribers — that is exactly CGNAT; as IPv6 spreads, that necessity fades.
Which one am I on?
Our tool shows the address you arrived from: dotted means IPv4, the long colon form means IPv6. Most modern networks run both (dual-stack) and browsers prefer IPv6 when available.
What changes for you?
In daily use, almost nothing — sites open in both worlds. The difference shows at the edges: for remote access to your home, IPv6 is the cleanest way past CGNAT; meanwhile some old devices and networks do not speak it. Should you disable IPv6? If nothing is broken, leave it on.
Our tool demonstrates every concept in this guide on your own connection: five-source location, VPN status, ASN and ISP — free, no signup.
Show my IPFrequently asked questions
Is IPv6 faster?
Not magically; but by skipping the CGNAT layer it can reduce latency on some networks. The difference is usually small.
Why does my IPv6 address keep changing?
Privacy extensions deliberately generate temporary addresses; your device rotates them to make tracking harder. That is design, not a fault.