How to Diagnose and Repair DNS Leaks

The use of modern VPN services for security and privacy is critical. Many use mobile applications or websites to conduct banking transactions, visit websites, communicate with users, and play online games. Few people would be happy to know that someone can spy on all your online activities. So, to hide your internet routine, programmers created a VPN system.

However, even the best services can fail, and their protection weakens. One type of those weak sides is a DNS leak. Although this problem cannot be catastrophic, the damage from such leaks can still bring a lot of inconvenience to the average Internet user. But all this can be either prevented or stopped.

In our article, we will tell you how you can test your DNS on leaking to the network and how you can fix this problem. We will also tell you how to avoid such issues and show you other types of data leaks on the network. Stay with us, read our article to the end and stay safe.

What Is DNS?

You may not know it, but the Domain Name System (DNS) is responsible for translating human-readable website addresses (like into the numerical IP addresses that computers use to connect to the internet. In other words, DNS allows you to type a website address into your browser and have it take you to the correct site.

In simple words, DNS can be a phone book for the internet. Just as you would look up a person’s phone number in a physical phone book to find their contact information, your computer looks up a website’s IP address in DNS to find its server on the internet so it can load the site.

When you type a website address into your browser, your computer will first contact a DNS server to request the IP address associated with that domain. ISPs and organizations worldwide maintain DNS servers and record all public IP addresses associated with registered domains.

Your computer will usually contact your ISP’s DNS server first, but if that server does not have the requested information, it will ask another server, and so on, until it finds the correct IP address. Once it has found the IP address, your computer can then contact the web server associated with that IP and load the requested website.

DNS may not be something you think about often (or ever), but it plays a crucial role in allowing you to surf the internet. Next time you type a website address into your browser and end up exactly where you wanted to be, remember DNS and all of its hard work!

What Is DNS Leak?

What Is DNS Leak?

A DNS leak is a security flaw that allows hackers to get around the DNS blocking and filtering meant to keep users safe on the internet.

Your ISP (Internet Service Provider) provides most DNS servers, but you can also use public DNS servers like Google Public DNS or Cloudflare’s Some VPN providers also offer DNS servers that you can use while connected to their VPN service.

When you use a VPN, all your internet traffic goes through the VPN server before it goes out to the wider internet. This means that your ISP will not be able to see which websites you are visiting, and neither will anyone else on the internet.

However, if your VPN connection leaks your DNS requests, your ISP (or anyone else) can see which websites you visit, even when using a VPN. This defeats the purpose of using a VPN in the first place, which is why ensuring that your VPN provider does not have any DNS leaks is crucial. But before you can fix this, you need to test VPN whether it leaks your DNS.

Why DNS Leaks Are a Big Problem

But before we get to testing DNS for leaks, we should consider several potential dangers associated with it for your Internet experience and personality. In this paragraph, we will discuss each risk and explain why it is sometimes worth checking the DNS for a leak and fixing this problem.

So, with a DNS leak, there are three dangers:

  • Leaking your actual IP address.
  • Viewing your internet habits (the sites you visit).
  • Tracking your online activities.

On the one hand, this leak may not be so dangerous for those who do not care about online privacy or use the default DNS server (for example, a provider’s). In this case, hackers and the ISP can still view the user’s data, sell info for advertising and commit cybercrime. In this case, there will be no DNS leak since you permit viewing the data by signing a contract with the provider.

If you worry about your privacy and use a DNS server that offers a VPN service, a DNS leak can lead to the following negative consequences.

IP LeakWhen your IP address is leaked, everything is simple. An attacker will be able to know the actual location of your computer and be able to find you.
Visits LeakWhile browsing your visits, the hacker can blackmail you, or sell your data to marketers who will analyze your online behavior and provide you with promotional offers in accordance to your shopping habits. Thus, they will manipulate you.
Online Activity LeakHackers can analyze your online activities, and after that, they can create phishing sites you may visit and infect your device with malware, which results in data loss or money theft.

Why Do DNS Leaks Happen?

DNS leaks can happen for a number of reasons. The most common causes are:

  • Your VPN software is not configured correctly and is sending some or all of your DNS requests outside of the encrypted tunnel. 
  • Your ISP’s DNS servers are hijacking your DNS requests and sending them outside of the VPN tunnel. 
  • The VPN server itself is leaking your DNS requests. 
  • Your computer’s network settings are not configured correctly and are sending some or all of your DNS requests outside of the VPN tunnel. 

How to Diagnose a DNS Leak

So, to understand if you have a DNS leak, you should do a small series of tests. To do this, you can use both special services that automatically test for DNS leaks and the command line on your computer. We’ll start with the easy way.

Online siteYou can use “” or “”. Here is a step-by-step guide on how to do a leaking DNS test:
1. Open the site and take the first test. For the first test, you do not need to connect to the VPN service so that you can see your real IP address and DNS server.
2. Once you get the results, you need to write down the data or take a screenshot.
3. Connect to VPN service.
4. Open the leak test site again and run the test.
5. After you have the results, compare the data.
6. If your new DNS address and IP address don’t match those of the first test, your VPN is doing a great job, and your data is completely protected. But if after the test any of the indicators match the previous ones, your DNS is most likely leaking into the network. In this case, change your VPN provider.
Terminal or command lineIn such a case, do the following:
1. You need to find your real IP address and DNS for the test. You will also need a working test server for checking DNS leaks. You can use “” for this.
2. Open a terminal. Type “ping -n 1”. Instead of “,” you need to enter the server name you will use. You can select it at “”
3. After pressing the “enter” key, you will get the result. In the IP address line, you can compare it with what you have chosen for the VPN. If the IP address matches the one you have without the VPN, you have a leak. In this case, you need to change your VPN provider.

In the next block, we will look at ways to solve the problem after you tested your VPN for leaks and your data was probably leaked.

How to Fix DNS leaks?

You can do a few things to solve the DNS address leak problem when you have tested it. Although they may require more advanced computer skills. After reading this article, watching a video on solving DNS problems is recommended. Thus, you can correctly solve your problem and not disrupt your Internet connection:

  1. The first option would be to exclude your VPN provider from the list of errors. To do this, ensure that your VPN is not the cause of the DNS leak. For this, you can conduct VPN leak tests on the sites indicated in the previous block. If your VPN is causing the problem, you just need to change your private network.
  2. If the solution does not help, you can clear the DNS caches. To do this, open your computer settings and launch a terminal. Then type “ipconfig/flushdns” and hit the enter button.
  3. If you’re using Windows, chances are Teredo works on your computer. You need to disable this program as it can leak your DNS address and bypass VPN protocols. To disable, open a terminal, right-click the input field, select “Run as an administrator,” and then type “netsh interface teredo set state disabled.”
  4. Change your DNS server to a more reliable one. To do this, you can search the Internet for a list of trusted addresses that improve Internet speed and are more secure. You can change DNS by looking at the block below. After this, test VPN for leaks again.

What Are the Benefits of DNS Changing?

Let’s say you decide to change your DNS after your DNS leaking test. What will you get as a result? Here are some of the benefits that you will get after changing the DNS server.

Increased Connection SpeedWith the new DNS server websites will load faster and it will be easier and more convenient for you to use the network. You will forget about long loads of pages for minutes. You will also get rid of sites’ elements or text disappearance. Now the internet will be fast and secure.
Security ImprovementIf your DNS server is leaking to the network, you will need to change it anyway. You can do it manually. It doesn’t matter whether you will be using a VPN or other methods. As soon as you change the DNS server, you will immediately receive a new level of protection, your data will be safe, and your identity will become anonymous again. However, it is still important to remember about precautions and be attentive to potential DNS leaks.
Fast DownloadsIf you like playing games, you are most likely facing the problem of slow game downloads. Given the fact that modern games can take up hundreds of gigabytes, the issue of speed becomes vital. However, did you know that by changing the DNS server, you can significantly improve your downloads from the network? This applies to both torrent and official downloads, such as from PlayStation or Xbox servers.
So, when connecting to the Internet, change your DNS server to or by yourself. With these two DNS server options, you can significantly increase your game downloads from the network. In addition, online games will also run more stable and without high ping. You can also find other secure DNS servers on the web by simply googling them.

Changing the DNS server only improves the situation and makes you more secure. A properly selected DNS server can improve your connection and increase the speed of downloading files from the network, which can be a great bonus for the user.

Tips for Avoiding DNS Leaks

Tips for Avoiding DNS Leaks

You successfully solved the problem of leaking your data. However, it would be best if you also consider some preventive measures.

You have 4 options:

  1. Change your VPN provider.
  2. Change your DNS server yourself.
  3. Block all traffic except VPN.
  4. Frequently test VPN leaks.

Apply all above mentioned measures. With them, you will be able to protect your data from leakage into the network. And scammers or Internet providers won’t be able to monitor your activities on the web. Now let’s take a closer look at each method.

Change Your VPN Provider

Changing your VPN provider is the easiest way to prevent such data leaks. To do this, draw conclusions about your VPN, uninstall the application, find a reliable provider (you can learn how to do this a bit later), and select a subscription plan. After that, you may enjoy a secure internet. Don’t forget to test a service for DNS leaking before switching to it.

Change Your DNS Server Yourself

If you are happy with your VPN provider, but you do not like the list of DNS servers that it offers, you can use Google Public DNS, and change your address to any you like from the available list.

For this:

  1. Open your network settings. This section may be in different sections/subsections on different operating systems, but you can always find it in the settings.
  2. After that, open the “change router settings” section.
  3. In the Properties menu, find Internet Protocol Version 4 (TCP/IPv4).
  4. Then choose either an automatic assignment of the DNS address or a manual entry.
  5. Choose the addresses you like and enter them. To do this, search for information regarding each address to find the most secure and fastest one.
  6. Before working with new DNS, test it for leak.

Block All Traffic Except VPN

Choose a VPN service that offers split tunneling or a kill switch to do this. Enable these two features in the VPN service settings to ensure that traffic goes only through the VPN service. Otherwise, your Internet connection will be off if the VPN service is disrupted. After blocking all the traffic, also test your DNS for leaking to find out whether it’s worth using or not.

Frequently Test DNS for Leaking

Like any disease in a person, program needs regular diagnostics. In this case, you need to run a test every time you connect to a VPN. If you find a problem, you need to start solving it. If there is no problem, your connection is secure, and nothing threatens your data.

Other Types of VPN Leaks

Besides DNS, there are other types of data leaks. They can also bring a lot of problems to your identity and data. Being aware of these leaks is also essential to keep your data protected and your network connection secure.

IP leaksDue to a disconnected VPN or problems with private network servers, your real IP address can be leaking to the Internet, and any attacker can get the data they need for the crime. You can fix this problem using the built-in Kill Switch function, blocking any traffic other than VPN, and using the support service. But to find it out, you should use VPN leak testing sources on the internet.
IPv6The best way to prevent IPv6 leaks is to disable IPv6 on your devices permanently. While this may sound drastic, it’s quite easy; most routers and operating systems have built-in options for disabling IPv6.
WebRTCIn this case, your real IP address will also become available to other users, which puts you at risk. The solution is to disable the WebRTC protocol. Every browser has its specific disabling procedure.

Disabling WebRTC Protocol

You can disable this protocol in different browsers:

  • Google Chrome:
    • Download the Google WebRTC Network Limiter extension.
    • Open the settings inside the extension.
    • Select “Use my proxy server”.
  • Firefox:
    • Enter “about: config” in the search field.
    • Enter “media.peerconnection.enabled” in the search bar.
    • Double-click on Preferences; the value changes from “true” to “false”, indicating that WebRTC doesn’t work anymore.
  • Safari:
    • Open settings.
    • Go to “Advanced.”
    • Show the Develop menu.
    • Open this menu from the top bar of your browser.
    • Select “Experimental Features” and press Remove Legacy WebRTC API.

How to Choose the Best VPN?

Before testing your VPN for leaks, choose one among different VPN providers on the market. It can be tricky to know which one to choose. In this paragraph, we’ll give you some tips on how to select the best VPN for your needs.

Consider Your NeedsThe first step in choosing a VPN is to consider your needs. Are you looking for a VPN for general browsing? Or do you need a VPN for specific purposes like streaming or downloading? Different VPNs offer different features, so choosing one that meets your needs is essential.
For example, if you’re looking for a VPN for general browsing, any reputable VPN will do the trick. However, if you’re looking for a VPN specifically for streaming Netflix or downloading torrents, you’ll want to ensure that the VPN you choose offers those features. Some VPNs even offer specialized servers for specific purposes like streaming or torrenting.
Check the Provider’s Logging PolicyWhen choosing a provider, it’s essential to check its logging policy. This refers to whether or not the provider keeps logs of your online activities. Ideally, it would be best to choose a provider that doesn’t keep any logs of your activities so that there’s no record of what you’ve been doing online. 
However, some providers keep logs but don’t share them with anyone. Others may share logs with law enforcement in response to valid legal requests. Check the provider’s logging policy before signing up so that you know what kind of data is being collected and how it’s being used.
Compare Price and ValueOnce you’ve considered your needs and checked the logging policy, it’s time to compare price and value. There are many free VPNs, but they usually have lower speeds and fewer features than paid VPNs. Plus, free VPNs often have shady business practices like selling user data or displaying ads (which can be annoying and intrusive).
Paid VPNs usually cost between $5 and $10 per month, although some providers offer discounts if you sign up for longer periods (e.g., six months or a year). When comparing prices, make sure also to consider what value each provider offers. For example, some providers offer more features than others, even at similar price points.
Look for a Reputable ProviderFinally, when choosing a provider, it’s essential to look for a reputable one. A reputable provider will have good reviews from other users, be transparent about its business practices, and offer good customer support. An excellent way to determine if a provider is reputable is to read online reviews from other users. You can also check out our list of the best (and worst) VPNs.


If you think you may have a DNS leak, there are a few ways to test and fix the issue. First, try running a DNS leak test. If you’re using a VPN, make sure it’s properly configured and doesn’t have any leaks. If you still have leaking DNS, there are a few things you can do to repair the leak. Try changing your DNS server settings or using a different VPN protocol. If all else fails, contact your ISP or network administrator for help.

With proper diagnosis and repair, you can fix DNS leaks and ensure your privacy and security online.


  1. What are Cloudflare DNS servers?

    You can use Cloudflare DNS servers as an alternative to the DNS servers provided by your ISP. They provide a faster and more secure way to resolve DNS requests. To use Cloudflare DNS servers, you will need to change the DNS settings in your operating system.

  2. How do you change your DNS server settings?

    Go to Control Panel > Network and Internet > Network and Sharing Center in Windows. Click on your active network connection, then click “Properties.” Under “Internet Protocol Version 4 (TCP/IPv4),” you will see your DNS server settings.

  3. What are some different VPN protocols?

    There are a few different VPN protocols that you can use. The most common are PPTP, L2TP/IPsec, and OpenVPN. Each protocol has advantages and disadvantages, so you must choose the one that is right for you.

  4. Who do you contact if you have a DNS leak?

    You should contact your VPN provider or network administrator for help if you have a DNS leak. They will be able to help you troubleshoot the issue and fix the problem.

  5. How do you prevent DNS leaks in the future?

    To prevent DNS leaks in the future, test your VPN regularly and make sure that you configured the app correctly. You can also change your DNS server settings or use a different VPN protocol. Contact your ISP or network administrator for help if you’re still having issues.

  6. Is WireGuard protocol safe for DNS leaking?

    Extremely secure WireGuard can only be used in conjunction with a reliable VPN. Modern security protocols used by WireGuard guarantee that its users won’t experience data leaks or cyberattack concerns. And the open-source system helps users see the transparency of the protocol.