ISP Leak & Blocking Detector
Find out whether your internet provider can see past your VPN, and whether it is quietly blocking websites on your connection.
- WebRTC leak test
- Blocked-site comparison
- Nothing is downloaded
1 Your connection
The address the internet sees, and the network that owns it.
- Provider
- Amazon.com, Inc.
- Network
- AS16509
- Country
- United States
2 WebRTC leak
Video-calling features in your browser can reveal your real address even when a VPN is on.
- Checking…
3 Blocked websites
Each site is checked by our server, outside your provider's network, and by your browser. If we can reach it and you can't, your network is blocking it.
| Site | Our server | Your browser | Result |
|---|
4 Browser fingerprint
A VPN hides your IP address, but not your browser. Your graphics card, fonts, screen, time zone and extensions form a fingerprint that websites can use to recognise you, even in a private window or on a VPN.
5 DNS leak
Even with a VPN, your device may still ask your provider's DNS servers to look up every site you visit, which tells them where you go.
How the tests work
- WebRTC: your browser asks STUN servers run by Google and Cloudflare what address it appears to have. If that differs from your connection address, traffic is escaping your VPN.
- Blocked sites: a connection that fails from your browser but works from our server points to a block on your network. Control sites that are never blocked confirm the test itself is working.
- We never download or store content from the tested sites. It's the same as checking whether a phone line connects.
Reading the results honestly
A failed browser connection is a strong hint, not proof. Ad blockers, security software and sites that refuse automated checks can also cause failures, so open a flagged site in a new tab to confirm. Some providers show a block page instead of cutting the connection, which this test can't see. Modern browsers also hide local addresses behind random .local names, which is good for your privacy.
How do I stop a WebRTC leak?
Turn on your VPN's WebRTC or leak protection. In Firefox you can set media.peerconnection.enabled to false in about:config. In Chrome and Edge, use your VPN's browser extension or a WebRTC-limiting extension.
Is it legal for my ISP to block websites?
Yes. UK providers block sites under High Court orders (mostly copyright infringement), sanctions and, optionally, parental-control filters you can switch off in your account.