What is a DNS Leak?
A DNS leak occurs when your DNS queries bypass your VPN tunnel and are sent directly to your ISP's DNS servers. This can expose your browsing history and online activities, even when using a VPN. DNS leaks defeat the purpose of using a VPN for privacy.
When you use a VPN, all your internet traffic, including DNS queries, should go through the encrypted VPN tunnel. However, due to various technical issues or misconfigurations, DNS requests might leak outside the tunnel, revealing which websites you're visiting to your ISP or other observers.
Common Causes of DNS Leaks
- IPv6 Leaks: Your device uses IPv6 but your VPN only handles IPv4 traffic
- DNS Configuration: Your system is configured to use specific DNS servers that bypass the VPN
- Transparent DNS Proxies: Some ISPs force their DNS servers regardless of your settings
- Windows Features: Windows 10/11 Smart Multi-Homed Name Resolution can cause leaks
- WebRTC Leaks: Browser WebRTC feature can expose your real IP address
How to Fix DNS Leaks
- Use a Quality VPN: Choose a VPN provider with built-in DNS leak protection
- Enable IPv6 Protection: Ensure your VPN handles IPv6 or disable IPv6 on your device
- Configure DNS Manually: Set your DNS servers to your VPN provider's DNS
- Disable WebRTC: In your browser, disable WebRTC to prevent IP leaks
- Use VPN DNS: Always use your VPN provider's DNS servers, not third-party ones
- Test Regularly: Run DNS leak tests periodically to ensure your VPN is working correctly
Understanding Test Results
When you run a DNS leak test:
- No Leak: Only your VPN's servers should be visible
- DNS Leak: Your ISP's or other DNS servers are visible alongside or instead of VPN servers
- Multiple IPs: Seeing multiple IP addresses might indicate a leak if they belong to different providers
Important: This test provides basic DNS leak detection. For comprehensive testing, use multiple test methods and check for WebRTC leaks separately.