With IPv4, your router sits between your devices and the internet using Network Address Translation (NAT). Internally your devices get addresses like 192.168.1.x — private, non-routable. Externally the whole household shares one public IP like 26.40.10.5. Your device's real address never touches the internet.

IPv6 eliminates NAT entirely. Every device gets a real, globally routable address. The IP on your machine is the same IP the rest of the world sees. No middleman.

An IPv6 address is 128 bits long — split cleanly in half. The first 64 bits identify your network (your /64 prefix, assigned by your ISP). The last 64 bits identify your specific device within that network.

That second half — 64 bits just for devices on your local network — means the number of addresses available within a single household is larger than the entire IPv4 internet. By orders of magnitude.

Here's the catch: every time you disconnect and reconnect — unplug your network cable, reconnect to WiFi, your device rotates its privacy address — you get a brand new globally unique IPv6 address. Same /64 prefix, different last 64 bits.

If this site counted raw IPv6 addresses, someone could unplug their cable, reload the page, unplug, reload — and inflate the counter endlessly. Each reconnect looks like a new visitor.

The /64 prefix is your network — not your specific device. It stays stable across reconnections. Counting /64s gives us the same thing IPv4 counting gives us: one unit per household or connection point, regardless of how many times the device rotates its address.

This makes the IPv4 vs IPv6 race meaningful. Both sides are counting the same thing: networks, not individual addresses.