DNS Leak Testing: Protecting Your Online Privacy

What is a DNS Leak and Why is it Dangerous?

Think of the DNS (Domain Name System) as the phonebook of the internet. It translates easy-to-read domain names (like google.com) into numerical IP addresses that computers understand.

Normally, when you use a VPN, your DNS queries are routed through a secure, encrypted tunnel to the VPN's private DNS servers. This keeps your browsing history hidden.

A DNS leak occurs when your operating system bypasses the secure VPN tunnel. Instead, it sends DNS queries directly to your internet service provider's (ISP) default DNS servers, exposing your activity.

Critical Warning: Even if a VPN masks your IP address, a DNS leak exposes your full browsing history, location, and ISP details to observers.

How DNS Leaks Happen

DNS leaks are usually caused by operating system configurations or network transitions. Here are the most common culprits.

• Teredo Tunneling: A transition technology that can route IPv6 traffic outside the IPv4 VPN tunnel.
• OS Smart Multi-Homed Name Resolution: A Windows feature that queries multiple DNS servers and selects the fastest response, sometimes bypassing the VPN.
• Manual DNS Settings: Misconfigured DNS settings on your network adapter that point directly to your ISP's servers.

How to Test for DNS Leaks

Checking if your DNS queries are leaking is quick and simple. Just follow these steps.

1. Disconnect from your VPN and run our DNS Leak Test to see your default ISP DNS servers.
2. Connect to your VPN and run the test again.
3. Compare the results. If the test shows any DNS servers belonging to your ISP or showing your real country, your DNS is leaking. If it shows only servers belonging to your VPN provider, you are secure.

How to Prevent and Fix DNS Leaks

If you discover a leak, you can secure your network by adjusting a few settings.

• Enable Leak Protection: Open your VPN client settings and ensure "DNS Leak Protection" and "IPv6 Leak Protection" are enabled.
• Use Secure DNS Providers: Manually configure your network settings to use secure, public DNS resolvers like Cloudflare (1.1.1.1 and 1.0.0.1) or Google (8.8.8.8 and 8.8.4.4). Use our DNS Lookup Tool to inspect host addresses.
• Disable Teredo (IPv6 Tunneling): Disabling Teredo in your command prompt stops Windows from routing IPv6 queries outside the VPN tunnel.

Along with DNS checks, always check for browser-level disclosures using our WebRTC Leak Test to keep your network identity fully anonymous.