GLOSSARY · INTERNET PROTOCOL VERSION 6
IPv6
IPv6 is the newer version of the addressing system, built to replace IPv4. Its addresses are 128 bits long and written in hexadecimal groups separated by colons, such as 2001:db8::1. The space is so large that every device can have its own public address, without sharing.
Why it matters
IPv6 removes the need for address sharing in many networks, but it creates new privacy and leak questions. A VPN or proxy that only handles IPv4 can leave your IPv6 traffic going straight out the normal way, exposing your real address. Many devices also rotate temporary IPv6 addresses to make tracking harder, but the first part of the address still identifies your network.
In practice
Whether you have IPv6 depends on your provider, router and device. Some websites are reachable over IPv6 only from networks that support it. If you use a VPN, check that it either carries IPv6 or blocks it, otherwise your IPv6 address may be shown. The IPv6 test reports whether your connection works over each version.
Related terms
- IPv4: IPv4 is the older and still most common version of the internet's addressing system.
- IP address: An IP address is a number that identifies a device or network connection on the internet, in the way a street address identifies a building.
- VPN: A VPN creates an encrypted tunnel between your device and a server operated by the VPN service.
- Subnet and CIDR: A subnet is a block of consecutive IP addresses treated as one network.