Glossary · VPN & tunneling

IPv6 leak

Also calledvpn ipv6 leak

Definition

An IPv6 leak happens when your VPN tunnels IPv4 traffic but lets IPv6 traffic bypass the tunnel — exposing your IPv6 address to destinations.

Explanation

In depth

Many older VPN configurations were built assuming IPv4-only. If your device supports IPv6 (most modern devices do) and the VPN client does not disable IPv6 or route it through the tunnel, then a destination that supports IPv6 will connect to you directly over IPv6, bypassing the VPN entirely — and see your real IPv6 address. Test for IPv6 leaks with ipleak.net. Modern VPN clients either block IPv6 outright or route it through the tunnel. Web proxies are largely unaffected because the browser makes all requests to the proxy domain over whichever IP version resolves, and the proxy handles both.

Related terms

VPNA VPN is a service that routes every network request from your device through an encrypted tunnel to a remote server.DNS leakA DNS leak happens when your device sends DNS lookups outside the VPN tunnel — revealing which sites you are visiting even though the traffic itself is encrypted.WebRTC leakA WebRTC leak exposes your real IP to a website via the browser's WebRTC API — even when a VPN is active — because WebRTC uses STUN outside the tunnel.IP addressAn IP address is a numeric identifier assigned to each device on a network — how packets know where to go.

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