Short answer: Firefox WebRTC behavior can vary by version, privacy settings, profiles, extensions, private windows, and VPN route. A WebRTC test helps separate Firefox browser candidates from the public IP shown by a normal page request.
A VPN can change normal browsing traffic while Firefox still reports WebRTC candidate categories that need review. The test is useful because it shows the current Firefox session, not because it certifies every app or browser profile.
Problem
- This page is for one current browser/session and route, not every app or future connection.
- The useful question is whether the visible signal matches the route you expected.
- One clean result is helpful, but it is not proof of anonymity, device safety, or a complete VPN audit.
Run the test
Start with WebRTC Leak Test. Keep the same browser and network when comparing before and after.
- Open the WebRTC Leak Test in the Firefox profile you actually use.
- Run it once before VPN or browser setting changes.
- Change only one thing: VPN server, extension, Firefox preference, or network.
- Run the same test again and compare candidates with the visible public IP.
- Use Safe Copy after the final run for a safe before/after summary.
How to interpret results
| Result | Usually means | What to do next |
|---|---|---|
| No public candidate | Firefox did not expose a public WebRTC candidate in this run. | Useful signal, not a full anonymity guarantee. |
| Local or masked candidates | Firefox may expose local categories or mask details depending on settings. | Compare with Chrome if you are isolating browser behavior. |
| Public candidate matches VPN | The candidate appears aligned with the VPN path. | Still check DNS and IPv6 if the goal is leak troubleshooting. |
| Public candidate matches ISP | Firefox may be exposing a non-VPN route in this session. | Review VPN app, split tunnel, proxy settings, and Firefox profile settings. |
| API blocked | Firefox settings, extensions, or policy may prevent candidate gathering. | Retest in the same profile after changing one setting at a time. |
Firefox-specific checks
- Compare normal and private windows only if your setup uses both.
- Check extensions that change proxy, VPN, privacy, or WebRTC behavior.
- Use the same Firefox profile for before and after testing.
- Do not change multiple preferences at once or the result becomes hard to interpret.
What to do after the result
If the result matches your expectation, keep the setup stable and save the receipt before changing anything else. If the result needs review, do not change several settings at once. Record the browser, device, network type, VPN server, DNS mode, and whether the test was run before or after connecting. Then change one layer, rerun the same test, and compare the new receipt with the previous one.
When two signals disagree, prioritize route ownership over labels. City and country labels can be approximate, but ISP, ASN, resolver owner, WebRTC candidate category, IPv6 reachability, and VPN state usually explain the next practical step. This keeps the page useful for real troubleshooting instead of turning the test into a one-off yes or no result.
Frequently asked questions
Why can Firefox and Chrome show different WebRTC results?
They use different browser implementations, settings, profiles, extension behavior, and privacy defaults. That is why browser-specific testing is useful.
Should I disable WebRTC entirely?
Only if that matches your use case. Disabling WebRTC can break calls and browser features. Prefer testing, understanding the result, and changing the least risky setting first.
Does Firefox WebRTC testing cover every app on the device?
No. It checks the current browser session. Other apps can use different network routes.
Limits and methodology
MyIPScan checks show observable browser and network signals for the current session. Results can change with browser profile, app route, VPN server, router, OS, carrier, DNS, and time. See the methodology and editorial policy.