DNS Leak

What is a DNS leak?

A DNS leak is a security flaw that allows ISPs to see all your DNS requests and track your browsing behavior, even if you are using a VPN service to conceal them.

DNS refers to the Domain Name System, which translates the name of a website (e.g., www.google.com) into a computer-readable IP address (e.g., By default, your DNS request will go to the ISPs’ DNS server, allowing them to see all the requests and track every action.

When you use a VPN, it encrypts your DNS requests and reroute them through its private DNS servers, preventing tracking by your ISP. However, DNS leak can allow some DNS requests to bypass the VPN's encryption and go straight to your ISP's DNS servers, enabling your ISP to see which websites and apps you're using.

How do DNS leaks happen?

There are a variety of things that can cause a DNS leak to occur, including:

1. VPN misconfiguration

If the VPN is not properly configured, for example, if the VPN does not have its own DNS servers or does not offer DNS leak protection, your DNS requests may be sent through the DNS servers provided by your ISP, resulting in a DNS leak.

2. No IPv6 support

Most IP addresses are still in IPv4 format, but a few IP addresses use the new IPv6 format. Some VPNs do not support the IPv6 format and therefore cannot encrypt these DNS requests, causing DNS leaks.

3. ISP settings

Some ISPs force users to use their DNS servers. Even if users manually set up third-party VPN servers as DNS servers, ISPs will redirect users' web activities to their own DNS servers, forcing DNS leaks.

4. Unstable network connection

An unstable network connection can cause the VPN to disconnect. In this case, the device sends the DNS request directly without encrypting it through the VPN. Some VPNs offer a "Kill Switch" feature that mitigates this by blocking all network traffic when the VPN disconnects.

5. Malware Interference

If your device is infected with some form of malware, it may be able to manipulate your DNS queries to send them outside the VPN path. This change can cause DNS leaks, exposing you to potential threats to your online activity and private information.

6. Incorrect DNS settings

Some operating systems(including Windows and macOS) can use their own DNS settings, or some web browsers(like Google) have built-in DNS handling mechanisms. If these settings are configured, DNS requests may not be sent through the VPN tunnel, resulting in a DNS leak.

How to detect DNS leaks?

You can follow these steps to detect DNS leak:

1. Connect to a VPN

Open and connect to your VPN. Make sure your custom DNS settings are configured correctly.

2. Visit the DNS Leak Test Site

X-VPN's DNS leak test site is a reliable option. The website will analyze your DNS requests.

3. Check the results

The tool displays the DNS servers used by your device and your IP address. If your IP matches the IP of the DNS server, there is no DNS leakage. This means that your DNS server is also provided by a VPN server and not by an ISP server.

How to fix DNS leak?

1. Manually configure DNS servers: You can choose trusted public DNS servers such as Google DNS (, or Cloudflare DNS (, This way, your DNS requests are going through these trusted common-public servers and not through the ISP-provided servers.

2. Use the VPN's DNS servers: Most reliable VPNs provide their own secure DNS servers. Check the VPN settings to make sure it is configured to use its DNS servers, not the ISP's DNS servers.

3. Choose a VPN with DNS leak protection: A VPN with built-in DNS leak protection is the most effective way to prevent these leaks in the first place. For example, X-VPN is an excellent VPN that offers top-notch security and built-in DNS leak protection.

4. Disable IPv6: Disable IPv6 protocol support through your router or firewall policy, as IPv6 traffic bypasses VPN routing. You can use an IPv6 Leak Test tool to check if IPv6 has been disabled.

5. Contact your VPN provider: If you're still experiencing DNS leaks, you can contact your VPN provider for more specific troubleshooting instructions.


1. What are the signs of a DNS leak?

When you are experiencing a DNS leak, you’ll see that you are using your ISP’s DNS server, even though you are connected to a VPN. You can check this with a DNS Leak Test tool to identify whether your online traffic is routed through your ISP or your VPN service.

2. Can a VPN prevent DNS leaks?

Yes, a well-configured VPN can effectively prevent DNS leaks with its own DNS server and DNS leak protection feature. Be sure to choose a VPN that specializes in DNS leak protection, such as X-VPN, as not all VPNs offer this feature.

3. Is it possible for DNS leaks to occur with mobile data?

Yes, DNS leaks can occur on any device that uses DNS to resolve website names, including mobile devices that use mobile data. This depends on the security measures of your mobile data connection and the applications you use. You can use X-VPN on your phone to prevent DNS leaks.