IPv4: the original mainstream Internet address format
IPv4 uses 32-bit addresses, usually written as four decimal numbers such as 203.0.113.25. The address space is limited, so NAT and address sharing became common as the Internet grew.
IPv6: a much larger address space
IPv6 uses 128-bit addresses written in hexadecimal groups, for example 2001:db8:1234::42. Its address space is vast enough to reduce the pressure that led to widespread IPv4 sharing.
Why do both still exist?
The Internet cannot switch every router, ISP, server and device at once. Many networks therefore use dual stack, where IPv4 and IPv6 operate side by side. Other deployments use translation or tunneling mechanisms to bridge gaps.
Does IPv6 reveal more?
An IPv6 address can be globally routable, but that does not automatically mean it exposes your exact identity. Modern operating systems commonly use temporary privacy addresses for outbound connections. Network prefixes can still provide clues about your ISP and connection.
Test your connection
Use our IPv4 / IPv6 connectivity test to see which protocols your current connection can reach.