Two versions of internet addressing
IPv4 and IPv6 are protocols for addressing and routing packets across networks. IPv4 is the older and still widely used version. IPv6 was designed to provide an enormously larger address space and improve the long-term structure of internet connectivity.
A typical IPv4 address looks like 203.0.113.10 and contains four decimal numbers. An IPv6 address uses hexadecimal groups, such as 2001:db8::10. Consecutive zero groups can be compressed with a double colon, which is why IPv6 addresses can have different-looking but equivalent written forms.
Address capacity
IPv4 uses 32-bit addresses, providing about 4.3 billion possible values before reserved ranges are considered. That once seemed ample, but global internet growth exhausted the freely available supply.
IPv6 uses 128-bit addresses. Its address space is so large that networks can assign globally routable addresses without relying on address conservation techniques designed for IPv4 scarcity.
Why IPv4 still works
Network Address Translation allows many private devices to share one public IPv4 address. Carriers may add another translation layer, known as carrier-grade NAT, so multiple subscribers share public addresses too.
NAT extended the useful life of IPv4, but it adds state and can complicate inbound connections, peer-to-peer services, and troubleshooting. IPv6 restores a more direct addressing model, although firewalls remain essential and devices should not accept unsolicited traffic by default.
Dual stack and transition
Most migrations are gradual. A dual-stack network supports IPv4 and IPv6 at the same time, and the operating system chooses an available route. Other transition systems translate or tunnel traffic when one side does not support the same protocol version.
The address shown by an IP checker depends on the connection used for that specific request. A device can have both versions, yet a site may see IPv4 if IPv6 is unavailable along the route or disabled by the network.
Security and privacy
IPv6 is not automatically more private or more dangerous than IPv4. Security depends on firewall policy, software configuration, network design, and how services handle data. Modern systems commonly use temporary IPv6 interface identifiers to reduce long-term device correlation.
Both versions reveal a routable network address to the destination. A privacy policy should therefore focus on whether the service stores, shares, or combines that address with persistent identifiers.