How to Perform a DNS Leak Test: Learn to Check & Fix DNS Leaks
Last Updated : 25 Mar, 2025
A DNS leak occurs when your computer sends DNS requests to incorrect servers or third parties, exposing your browsing activity. However, the A DNS leak test is a simple check to see if your Virtual Private Network (VPN) is fully protecting your online privacy. The test works by analyzing which DNS servers your device is contacting when you visit any site. So, if you have a doubt, then explore the complete guide on how to perform a DNS leak test and check your DNS leaking or not.
How to Perform a DNS Leak TestRoot Cause of DNS Leak
After knowing what DNS leak is let's explore the main root cause behind the DNS leak
- Misconfigured Network Settings: Manual changes or software updates may revert DNS settings to unsafe defaults (e.g., ISP’s servers).
- Faulty VPN/Proxy Services: Some VPNs fail to route DNS queries. This happen due to the misconfigured DNS settings.
- Malware or Cyberattacks: Malicious software can hijack DNS settings, redirecting traffic to phishing servers.
- IPv6 Compatibility Issues: Many VPNs don’t support IPv6, causing leaks if your ISP uses it.
- WebRTC Vulnerabilities: Browsers like Chrome/Firefox may expose your IP via WebRTC APIs.
- ISP DNS Hijacking: Some ISPs forcibly redirect DNS queries to monitor traffic.
What are the Types of DNS Leak Test
There are various types of DNS leaks, each resulting from different technical situations. Here are the main types:
Default DNS Leak
- A default DNS leak happens when your device ignores your VPN and sends your website requests straight to your internet provider’s servers. This can occur if your VPN isn’t set up right or if it disconnects without you noticing. When this leak happens, your provider can see every site you visit, ruining the privacy you expect from your VPN.
IPv6 DNS Leak
- An IPv6 DNS leak occurs because your device uses a newer internet system called IPv6, but your VPN might only protect the older system, IPv4. If the VPN doesn’t handle IPv6 traffic, your website requests sneak past it and go straight to your provider or others. This means your browsing isn’t as hidden as you think.
Transparent DNS Proxy Leak
- A transparent DNS proxy leak is when your internet provider uses a sneaky trick to take over your DNS requests, even if you’re using a VPN. They force their own servers into the mix, ignoring what your VPN wants to use. As a result, your VPN can’t protect you, and your provider knows exactly what you’re doing online.
Configuration Error DNS Leak
- A configuration error DNS leak comes from a mistake in how your VPN or device is set up. Maybe you accidentally picked the wrong DNS servers, or there’s a glitch in the VPN software. When this happens, your website requests slip outside the VPN’s safe tunnel, letting your provider or others peek at your online activity.
How to Perform a DNS Leak Test
Well if you are experiencing any DNS leak, then you can easily perform the DNS leak test by following the below steps. So, follow the steps and check you DNS leak.
Step 1: Disconnect Your VPN
- Before testing, turn off your VPN to see what your connection looks like without it. This gives you a baseline to compare against later. So open your VPN app and click "Disconnect" or toggle it off.
Step 2: Open DNS Leak Test Website or Software
- Once you have connect to your VPN then open the DNS Leak Test website like "IPLEAK.NET", "DNSLEAKTEST.COM", "DNSLEAK.COM" to perform the DNS leak test.
NOTE: If you're using a paid VPN service like NordVPN, Surfshark, ExpressVPN, AstrillVPN, or CyberGhost, they offer their own DNS leak testing tools. In this article, we will utilize a website for the DNS leak test.
Step 3: Run the Baseline Test
- With your VPN off, go to the test website and start the DNS leak. In this test you will get your DNS servers listed (e.g., your ISP’s servers) and their locations.
Step 4: Connect to VPN
- Now, the first steps is to connect to you VPN so we can check the DNS leaking.
Step 5: Run the DNS Leak Test Again
- Return to the test site and repeat the process with your VPN active. Check the DNS servers shown. They should belong to your VPN provider and match the server location you chose (e.g., London).
Step 4: Check the Test Result
- After the test is complete, the website will display the DNS servers your device used to resolve domain names. If the IP address shown is different from the DNS server provided by your VPN, it means you have a DNS leak.
How to Fix DNS Leak
If you found that your DNS test is failed then you can follow the below steps to fix the DNS leaking:
- Check VPN Settings: Look for "DNS Leak Protection" or "Custom DNS" options in your VPN app and enable them.
- Manually Set DNS: Use secure DNS servers like Google (8.8.8.8, 8.8.4.4) or Cloudflare (1.1.1.1, 1.0.0.1) in your network settings.
- Switch VPNs: If the problem persists, consider a VPN with stronger leak protection.
Benefits of DNS Leak Test
- Ensures Online Privacy: DNS leak tests confirm that your browsing data is not exposed to your ISP or any other external entities, which is especially important if you're using a VPN to protect your privacy.
- Verification of VPN Service: Running a DNS leak test regularly allows you to check if your VPN is functioning correctly and if it is providing the level of privacy you expect.
- Helps Troubleshoot VPN Problems: If you're experiencing issues with your VPN, such as slower speeds or exposed browsing data, a DNS leak test can help you identify whether a DNS leak is the cause.
- Increases Security: Identifying and fixing DNS leaks ensures that your DNS requests are secure, reducing the risk of hackers or other malicious actors intercepting your traffic.
Conclusion
Performing a DNS leak test is a small effort with big rewards. It safeguards your privacy, secures your data, confirms your VPN’s reliability, and helps you access the content you want all while troubleshooting potential issues. Whether you’re a casual internet user or someone who values anonymity, this quick check is an essential habit to keep your online world safe and seamless.
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