DNS leak
When name lookups travel to your ISP’s resolver instead of through the tunnel, exposing every domain you visit.
Glossary
WebRTC leak
What is WebRTC leak?
WebRTC leak is when a browser exposes your local or real address through the peer-connection API, independently of the VPN tunnel. A page can ask the browser to enumerate the addresses it can reach, in a few lines of JavaScript, and report back whatever it finds.
Why it matters
A page can ask the browser to enumerate the addresses it can reach, in a few lines of JavaScript, and report back whatever it finds.
What most explanations leave out
The common claim that WebRTC bypasses a VPN is wrong. WebRTC discovers your public address through STUN over the ordinary socket API, so under a full tunnel those packets go through the tunnel and return the VPN’s address. It exposes your real one only where a leak path already exists â split tunnelling, an unblocked IPv6 route, or a second active interface. Local-network addresses have been mDNS-obfuscated by default in the major browsers since around 2019. Treat it as an amplifier of misconfiguration rather than a hole in a correctly routed VPN.
Related terms
IPv6 leak
When a tunnel carries only IPv4 while your connection also has IPv6, so IPv6-capable sites see your real address.
Referenced from
Questions
- What is WebRTC leak?
- When a browser exposes your local or real address through the peer-connection API, independently of the VPN tunnel.
- Why does WebRTC leak matter when choosing a VPN?
- A page can ask the browser to enumerate the addresses it can reach, in a few lines of JavaScript, and report back whatever it finds.
- What do most explanations of WebRTC leak leave out?
- The common claim that WebRTC bypasses a VPN is wrong. WebRTC discovers your public address through STUN over the ordinary socket API, so under a full tunnel those packets go through the tunnel and return the VPN’s address. It exposes your real one only where a leak path already exists â split tunnelling, an unblocked IPv6 route, or a second active interface. Local-network addresses have been mDNS-obfuscated by default in the major browsers since around 2019. Treat it as an amplifier of misconfiguration rather than a hole in a correctly routed VPN.
Terms are defined here because they appear in our scoring rubric or in provider reviews, not to fill a glossary.