WebRTC-lektest
Met WebRTC kunnen webpagina's directe verbindingen opzetten, en daarvoor verzamelt de browser zijn eigen adressen. Deze test laat zien wat een pagina op die manier te weten kan komen.
De test vraagt de openbare STUN-server van Cloudflare (stun.cloudflare.com, poort 3478) welk adres die ziet, zoals een videobelpagina zou doen. Cloudflare ziet dus uw adres; er gaat niets naar onze server.
Deze tekst is nog niet beschikbaar in het Nederlands. Hij wordt in het Engels getoond tot er een vertaling is gepubliceerd.
WebRTC lets a web page open direct audio, video and data connections, the technology behind browser video calls. To find a direct path between two devices, the browser gathers candidates: its local addresses, and its public address as seen by a STUN server on the internet.
Before 2019, any page could read your local network addresses this way. Modern browsers hide them behind random .local names (mDNS), so a page sees something like 8f3c….local instead of 192.168.1.23.
The public address is the interesting part for VPN users. Normally it is the same address every website sees. If the VPN only tunnels some traffic, WebRTC can reveal the address of your real connection. This test gathers candidates exactly as a call would, using Cloudflare’s public STUN server, and compares the public address with the one this page sees.
Veelgestelde vragen
Who sees my address during the test?
Cloudflare's STUN server (stun.cloudflare.com), which has to see an address to report it, just as in any video call. Nothing from the test is sent to our server.
How do I stop a WebRTC leak?
Use a VPN app that routes all traffic, including UDP, through the tunnel; many have a WebRTC or leak-protection setting. Firefox can disable WebRTC entirely (media.peerconnection.enabled in about:config).
The test shows an IPv6 address I did not expect.
Some VPNs tunnel only IPv4. If WebRTC shows a public IPv6 address from your own provider, your IPv6 traffic bypasses the VPN.