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What are IPv6 Privacy Extensions?

IPv6 privacy extensions are a feature designed to protect user privacy by preventing long-term tracking of devices based on their IPv6 address.

Devices can automatically generate their own IPv6 addresses using a method called stateless address autoconfiguration (SLAAC). Typically, part of that address stays stable over time, which makes it possible to track a device across websites or sessions. A privacy extension solves this problem by adding temporary, random addresses.

How do IPv6 privacy extensions work? Your device still has a stable IPv6 address for things like incoming connections. But it can also randomly generate IPv6 addresses that are used for outgoing traffic (like browsing websites) and changed regularly. These temporary addresses appear unrelated to each other and expire after a short time.

In general, IPv6 privacy extensions are turned on by default in Windows, macOS, iOS, Android, and other common devices. If you’re using Linux, though, you might need to check that it’s active.

Why do IPv6 privacy extensions exist? Without the extension, your device could act as a persistent identifier, letting websites track you over time simply by logging your IP. With a privacy extension, your IP keeps changing and tracking becomes much harder.

Questions about IPv6? We’ve answered them.