You connect through a VPN, so your real IP address is hidden — or so you assume. A WebRTC leak can quietly undo that, handing a website your true address while the VPN is still on.
What WebRTC is
WebRTC is a browser technology for real-time communication — video calls, voice chat and similar features that work directly inside a web page without a plugin. To connect two users efficiently, WebRTC needs to discover the network addresses each device can be reached at. That discovery is useful for calls — and it is also the source of the leak.
How the leak happens
To set up a direct connection, WebRTC asks your system for its addresses and can share them with the web page. The problem: this process can surface your real IP address even when your browser traffic is otherwise routed through a VPN. A page running a small script can read what WebRTC reports. The VPN is still working for ordinary traffic — but WebRTC took a different path.
How to check
You can test for a WebRTC leak. With your VPN connected, visit a reputable IP-leak test page. It will show the addresses your browser exposes. If an address there matches your real, non-VPN IP, WebRTC is leaking. If it shows only the VPN's address, you are fine.
How to prevent it
There are a few fixes. Some browsers have a setting to disable or restrict WebRTC; some privacy-focused browsers handle it by default. Extensions exist that block WebRTC leaks specifically. And some VPN clients include WebRTC-leak protection. The right fix depends on your setup, but the goal is the same: stop WebRTC from revealing addresses the VPN is meant to hide.
The takeaway
A VPN routes your traffic, but WebRTC can take a shortcut around it and expose your real IP. It is a well-known leak with well-known fixes. If you rely on a VPN for privacy, test for a WebRTC leak once — it is the gap most people never check.