What is WebRTC leak?
A WebRTC leak is when a browser's real-time communication APIs reveal your true IP address even though you're behind a VPN or proxy. WebRTC gathers candidate IPs via STUN to establish peer connections, and those candidates can expose the underlying public or local IP a VPN was meant to hide.
Because WebRTC operates below the page's normal network layer, it can surface an IP that differs from the one your HTTP requests appear to use — a strong tell that the visible IP is a proxy or VPN.
Modern browsers limit this with mDNS hostnames for local addresses, but a public-IP mismatch between WebRTC and the HTTP source remains a useful detection signal.
How IPLogs handles it
IPLogs can compare a WebRTC-reported IP against the HTTP source IP; a mismatch indicates the connection is being relayed.