DNS Leak Test

What Is a DNS Leak?

To understand a DNS leak, you first need to understand DNS (Domain Name System). Think of DNS as the phonebook of the internet. When you type a website name (like outbyte.com) into your browser, your device contacts a DNS server to translate that name into an IP address the computer understands.

Usually, your ISP (internet service provider) handles these requests. This means they can see every website you visit. When you use a VPN, your traffic—including these DNS requests—is encrypted and sent through a secure tunnel, hiding your activity from your ISP.

So, what is a DNS leak? A DNS leak happens when your device accidentally ignores the secure VPN tunnel and sends your DNS requests directly to your ISP’s servers instead.

Why is this dangerous? Even though your traffic might look encrypted, the “phonebook” lookup is exposed. Your ISP (and anyone eavesdropping on the network) can see exactly which websites you are visiting, defeating the primary privacy purpose of using a VPN. Running a DNS leak check is the only way to confirm if your browsing history is truly private.

How a DNS Leak Test Works

Our DNS leak checker prompts your browser to load specific, unique domain names, forcing it to send a fresh request to a DNS server to find the address. The tool then captures which DNS server made the request and compares its IP address against your public IP address.

If you are using a VPN, the DNS request should come from the VPN provider’s server. If the request comes from your ISP’s server, you have a leak.

This simple test for a DNS leak reveals whether your system (and VPN provider) is respecting your privacy or exposing your online activity behind your back.

What Your Results Mean

After you run a check for a DNS leak, you will see a list of IP addresses (DNS endpoints), who they belong to, and their locations. Here is how to interpret them:

1. If the results you get on our DNS leak test website show DNS servers that belong to your VPN provider, you are safe. This means your encrypted tunnel is working correctly, and your ISP cannot see your web requests. The location shown should match the server location you selected in your VPN app, not your physical home address.

2. If the results show servers owned by your local ISP, or if the location matches your real physical location while your VPN is on, you have a leak, and your privacy is compromised. This means:

   • Your ISP knows what websites you are visiting.
   • The websites you visit may be able to see your true ISP location.
   • Your VPN is encrypting your data, but not your destination requests.

Why DNS Leaks Happen

You might wonder, “I bought a premium VPN, so why do I need a VPN DNS leak test?” Unfortunately, software and operating systems often prioritize speed over privacy, leading to accidental leaks.

• Windows Smart Multi-Homed Name Resolution (SMHNR): In newer versions of Windows (10 and 11), the OS sends DNS requests to all available network adapters at once and accepts the fastest response. If your ISP’s gateway is faster than the VPN tunnel, Windows will use the ISP, causing a leak.

• IPv6 mismatches: The internet is slowly moving from IPv4 to IPv6 addresses. If your VPN only supports IPv4 but your ISP enables IPv6, your computer might send IPv6 requests outside the encrypted tunnel. This is a very common cause of leaks.

• Teredo tunneling: This is a transition technology that gives full IPv6 connectivity for IPv4-capable hosts. It can sometimes bypass VPN tunnels entirely.

• Browser WebRTC: Browsers use WebRTC for video and voice chats. However, it can sometimes reveal your true local IP address even if you are behind a VPN.

How to Fix and Prevent DNS Leaks

If your DNS leak test shows that your ISP is still visible, don’t panic. Security is a process, not a toggle switch. Here is how to stop a DNS leak to secure your connection and keep it that way.

How to fix a DNS leak

If you just ran a test and it showed a leak, you need to plug the hole immediately. The problem usually lies in your VPN configuration or your computer’s network settings. Here is how to fix it right now:

• Enable your VPN’s DNS leak protection: Open your VPN application settings and look for a feature labeled “DNS leak protection” or “IP/DNS protection.” Ensure this is toggled on. Many VPNs disable this by default to improve connection speed, but the trade-off is your privacy.

• Activate the kill switch: A kill switch is a safety net. If your VPN connection drops for even a second, your computer will try to reconnect to the internet using your normal ISP connection, exposing your DNS requests. Turning on the kill switch ensures that if the VPN drops, your internet cuts off completely until the secure tunnel is re-established.

• Manually change your DNS: Even if your VPN fails, you can ensure your ISP doesn’t see your data by forcing your computer to use a secure, third-party DNS provider. Go to your network adapter settings and change your DNS server addresses to a neutral provider like Cloudflare (1.1.1.1) or OpenDNS. This ensures that even if a leak happens, your ISP isn’t the one logging the requests.

• Clear your DNS cache: Sometimes old data gets stuck and needs a nudge to leave. Open the Command Prompt and type ipconfig /flushdns to wipe the slate clean.

How to prevent a DNS leak

Once your connection is secure, you need to ensure it stays that way. Operating systems often update and reset settings, so stopping a DNS leak permanently requires a few proactive changes:

• Disable IPv6: If your VPN doesn’t support IPv6, it’s best to disable it in your network adapter settings. This is often the most effective remedy against recurring DNS leaks.

• Patch WebRTC leaks in your browser: Disabling WebRTC in your browser’s advanced settings or installing a browser extension specifically designed to block it ensures it doesn’t reveal your real DNS while you’re using a VPN.

• Regular auditing: Network configurations change. A driver update or a new software installation can revert your security settings without warning. The only way to be certain of your privacy is to make the DNS leak test a part of your regular routine.

Following these simple rules and running regular checks using the best DNS leak test tools, like Outbyte’s, will ensure that your device relies solely on the encrypted VPN tunnel and your privacy stays protected.

Frequently Asked Questions (FAQ)