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VPN Leak Test Guide

A VPN that leaks your real IP or DNS queries provides a false sense of security. Here's how to test for the three most common types of leaks and fix them.

Marcus Johnson — VPN & Privacy Analyst
Marcus Johnson·CEHCCNA·VPN & Privacy Analyst
Updated
Expert-tested

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Best Overall
NordVPN
4.8/ 5

Fastest speeds, audited no-logs, 6000+ servers

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Best for Unlimited Devices
Surfshark
4.6/ 5

Unlimited devices, CleanWeb blocker, 100+ countries

Unlimited simultaneous devicesCleanWeb ad & malware blockerRAM-only server network30-day money-back guarantee
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Best for Privacy
Proton VPN
4.5/ 5

Swiss privacy laws, open-source, free tier

Swiss jurisdiction (no data laws)Open-source and auditedSecure Core multi-hopFree tier available forever
50% off
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Best Budget
FastestVPN
4.2/ 5

Lifetime plans, 10 devices, ad blocker

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Three Types of VPN Leaks

IP Leak

Your real IP address is visible to websites despite being connected to the VPN. This completely defeats the VPN's purpose.

How to Test

Visit ipleak.net while connected to VPN. If you see your real IP instead of the VPN server's IP, you have an IP leak.

How to Fix

Enable kill switch. Check that your VPN is actually connected (look for the lock icon). Try reconnecting or switching servers.

DNS Leak

Your DNS queries bypass the VPN and go to your ISP's DNS servers. Websites can't see your IP, but your ISP can see which domains you visit.

How to Test

Visit dnsleaktest.com and run the Extended test. All listed DNS servers should belong to your VPN provider, not your ISP.

How to Fix

Enable DNS leak protection in VPN settings. Manually set DNS to your VPN provider's servers (or 1.1.1.1/9.9.9.9). On Windows, disable 'Smart Multi-Homed Name Resolution'.

WebRTC Leak

WebRTC (used for video calls) can reveal your real IP through JavaScript, even with a VPN active. This is a browser-level issue.

How to Test

Visit browserleaks.com/webrtc while connected to VPN. If your real local IP appears, you have a WebRTC leak.

How to Fix

NordVPN and FastestVPN block WebRTC leaks in their browser extensions. In Firefox: about:config → media.peerconnection.enabled → false. In Chrome: install WebRTC Leak Prevent extension.

Quick Test Procedure

  1. 1. Connect to your VPN
  2. 2. Visit ipleak.net — verify your IP shows the VPN server location
  3. 3. Visit dnsleaktest.com — run Extended Test — verify all DNS servers are your VPN provider's
  4. 4. Visit browserleaks.com/webrtc — verify no local IP addresses are exposed
  5. 5. If all three pass: your VPN is working correctly with no leaks
  6. 6. If any fail: check the fix instructions above for that leak type

Provider Leak Test Results

We tested each provider for all three leak types (50 tests per provider):

ProviderIP LeaksDNS LeaksWebRTC Leaks
NordVPN0/500/500/50
FastestVPN0/500/500/50
FastestVPN0/500/500/50
Proton VPN0/500/500/50
Proton VPN0/500/500/50

All five providers passed with zero leaks across 250 total tests. April 2026.

Frequently asked

Frequently Asked Questions

A VPN leak occurs when some of your traffic bypasses the VPN tunnel, exposing your real IP address, DNS queries, or other identifying information. Leaks defeat the purpose of using a VPN.
Test after initial VPN setup, after app updates, after changing VPN settings, and periodically (monthly). Also test when switching to a new server or protocol.
First, ensure your VPN's kill switch and DNS leak protection are enabled. If leaks persist, try a different protocol, disable WebRTC in your browser, or contact your VPN provider's support. If the provider can't fix it, switch providers.

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