IPv4 and IPv6 are two versions of the Internet Protocol. Both are used to identify devices and route traffic, but they look different and were designed for different eras of the internet. IPv4 addresses look like 203.0.113.10. IPv6 addresses are longer and use hexadecimal notation, such as 2001:db8:85a3::8a2e:370:7334.
Why IPv6 Was Created
IPv4 has a limited address space. As the internet grew to include phones, tablets, home routers, servers, smart devices, and cloud systems, the available IPv4 pool became strained. IPv6 provides a vastly larger address space, making it easier for networks to assign unique addresses without relying as heavily on address sharing.
Does IPv6 Replace IPv4?
Not all at once. Many networks run dual stack, which means they support IPv4 and IPv6 at the same time. Some websites and services are available on both. Others still depend on IPv4. This transition period is why you may see both an IPv4 and IPv6 address when checking your connection.
Privacy and IPv6
Early IPv6 configurations sometimes used stable interface identifiers that could make devices easier to recognize across networks. Modern systems commonly use privacy extensions or temporary addresses to reduce that risk. Still, your IPv6 address can reveal your network provider and approximate location in the same broad way an IPv4 address can.
VPN and IPv6 Leaks
If a VPN only tunnels IPv4 traffic but your device also has IPv6 connectivity, some traffic may bypass the VPN. This is called an IPv6 leak. A good VPN should either support IPv6 inside the tunnel or safely block IPv6 traffic while connected. Checking both address types is a useful habit when privacy is important.