STUN Server Test

What this STUN server test checks

This tool creates a real WebRTC peer connection in your browser and uses the STUN URL you provide during ICE gathering. The most important signal is whether the browser receives a srflx candidate. That candidate indicates that STUN discovery succeeded and that the browser learned a public-facing address through the configured server.

Testing custom STUN endpoints

Enter a standard STUN URI such as stun:host:3478 and run the test. The results table shows every candidate returned by the browser, including transport protocol, address, port and source server. This makes it easier to compare public STUN endpoints, validate your own infrastructure or investigate why WebRTC behaves differently across office, mobile and home networks.

STUN is only one part of WebRTC connectivity

A working STUN server does not prove that every peer-to-peer call can connect. Some NAT and firewall environments prevent direct paths even when STUN succeeds. In those cases a TURN relay is required. Use the TURN server test to verify relay allocation, or the ICE candidate test to inspect the complete candidate set.

If you are troubleshooting the full browser experience rather than a server endpoint, run the main WebRTC test, which also checks WebRTC API support, camera and microphone access.