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What Is a DNS Leak? How To Test and Fix Them

Daren Low
May 25, 2024


From online banking to shopping – we love the internet. But beyond the glamor and ease the web provides, you could be exposing your private information for the world to see.


Even if you have a tool like a VPN (Virtual Private Network) to ensure online anonymity, privacy, and security, it’s possible for these to fail or malfunction, leaving your DNS queries visible to all and sundry.


But what are DNS leaks, and how do you protect your device against them? We have all the answers to these questions and more in this article. So, join us as we reveal the juicy details to you. Shall we?



What is a DNS?


Accessing any site looks easy; you can type or any domain name on your browser, and the result pops up. But while it seems seamless on the outside, a lot is happening behind the scenes.


What happens is that the Domain Name System (DNS) converts the domain name (for example, into a numerical IP address (35.2444.246.259). This is typically done by the user’s ISP, using its DNS servers.



What are DNS Leaks?


DNS leak diagram


Each time you input a URL, your device reaches out to a DNS server requesting the URL’s IP address. A DNS leak is said to have occurred when this IP address is visible for all to see rather than being masked.


A DNS leak occurs when your ISP can track your online activities, regardless of whether you are connected to a VPN. This means your ISP can hack your account and gather your browsing habits. This is done due to several reasons, including:


  • To make money off your data
  • To sell off your data to marketing companies
  • To enable the marketing companies to use your information to send targeted ads to promote their brand.


Also, your information can fall into the hands of online predators who can use it for more dangerous purposes, including impersonation and fraud.



Dangers of a DNS leak


There are many dangers to DNS leaks. First, DNS leaks expose your real IP address, and this robs you off your privacy, safety, and anonymity. It also enables unauthorized persons to track your online activities.


Besides, DNS poses a serious security risk because your browser uses your DNS to detect websites you are accessing. Your device then enquires from the DNS server, and the server, in turn, reveals the directions that tell your web browser how to get to the website you are searching for.


This process leaves some cookie-crumb trails to your DNS or ISP, which exposes you to danger. Furthermore, hackers can access your DNS server and redirect you to a phishing or proxy site; these malicious sites can steal your data, impersonate you and carry out other mischievous acts.



How can I check if my VPN is protecting me?


Connecting to a VPN isn’t a guarantee you are safe. Your DNS may be leaking without your knowledge. Hence, it’s important to conduct periodic tests to determine if your DNS leaks. Here are some tests you can take to determine your online safety:


1. How to check if your DNS leaks


The following steps will help you determine if you have a DNS leak:


Step 1: Switch off your VPN.


Step 2: Visit the DNS leak site.


Step 3: Write down the information the website displays. This will include your ISP’s IP address, ISP’s name, hostname, and geographical location.


New York IP address

First, check what IP is displayed before you connect to your VPN.


Step 4: Turn on your VPN and choose another geo-location separate from the previous one.


Step 5: Return to the DNS leak site and conduct a DNS leak test. If you can see a different IP address, IP name, and geo-location, then you are safe and not suffering from a DNS leak. Otherwise, your VPN is leaking.


Germany IP address

Connect your VPN and compare the results.


Fortunately, the DNS leak site and others like it can check your VPN connection for possible DNS leaks, but beyond that, they will advise you on how to fix any detected leak.


2. How to check the status of your DNS


You can also check your DNS status.


DNS leak standard and extended test


To do this, choose the Standard or Extended test feature on the DNS leak site. If you are connected to a VPN, yet the DNS server displayed isn’t the same as your ISP, your internet traffic is secure.



What Causes VPNs to leak DNS?


One of the primary duties of a VPN is to mask your IP address, thus preventing your ISP from detecting your online presence. Yet, your DNS can still leak despite being connected to a VPN, and this is due to several reasons, including:


  1. Manual Configuration of the VPN
    When you manually configure your VPN, you increase the chances of DNS leaks. The increase in danger also depends on the configuration of the device’s operating system.
  2. Manual DNS Configuration
    Sometimes, DNS leaks occur because you need to configure your device’s operating system to connect to the VPN’s DNS leak protection feature. While most VPNs have the feature turned on by default, you may have intentionally or unintentionally turned it off manually, thus exposing you to DNS leaks.
  3. A Hacker Has a Hold of your Router
    When connected to public WIFI, such as those in coffee shops, airports, or libraries, an attacker may gain control of your router. The hacker can trick your device into routing your DNS traffic outside your VPN, which exposes you to many dangers.



How do the best VPNs protect against VPN Leaks?


Using a reputable VPN is important to help prevent DNS leaks. That’s why we’ve tested and rounded up the best VPNs that have proved themselves as secure solutions.


Not only do they offer the best protocols for VPN, these VPN offer watertight security features, the best encryption standards, and tools to prevent DNS leaks. While several VPNs and most claim to prevent DNS leaks, not all are true to their words. However, the underlisted VPNs are the best you can find around:


1. ExpressVPN


ExpressVPN DNS


ExpressVPN is one of the best VPNs available. The VPN has fast internet servers, features a zero log policy, and ensures end-to-end encryption of all traffic going between your device.


Upon inputting a URL or clicking a link, the VPN sends the URL to a DNS server operated by ExpressVPN through its encrypted tunnels. The DNS server then detects the IP address and sends it back to the VPN and you. This all happens within seconds, and no traffic is lost in the process. Fortunately, no manual configurations are required as the DNS leak feature is turned on by default.


Read our full ExpressVPN review for more info.


2. Surfshark VPN


surfshark VPN


Surfshark VPN is another excellent choice. The VPN has military-grade protection features to prevent DNS leaks. Rather than allow your DNS servers to route through your device, Surfshark blocks all DNS requests, routing them through its safe, secure, and encrypted tunnel. Besides, the VPN keeps no logs; hence, your privacy is further assured. With SurfShark VPN, you get faster DNS servers, zero connection logs, and end-to-end traffic encryptions.


Read our full Surfshark review for more info.


3. NordVPN



Dubbed the “super safe double encryption master,” NordVPN also features a DNS leak prevention function that can be activated with the click of a button. The DNS leak protection feature is turned on by default, thus, protecting you from the moment you connect to it.


The VPN ensures DNS leak protection by ensuring it uses only DNS servers run by the VPN. Hence, all your DNS queries pass through an encrypted tunnel and come back to you through the same channel. This way, your DNS never leaks, and you don’t have to worry about spies and hackers.


Read our full NordVPN review for more info.



Avoid DNS Leaks, Protect Your Data


You don’t want your boss to find out about those job application websites you went to, do you? I bet the answer is a big NO. Yet, that’s what DNS leaks can lead to. Fortunately, there are several ways to prevent these leaks, but the most effective tool to use is a VPN.


The best VPNs will guarantee that your DNS does not leak, and your internet activity does not get traced to you. But even while connected to a VPN, DNS leaks can still occur if you’ve not chosen a reputable brand, or haven’t set it up correctly.


However, a simple DNS leak test can help detect any leak and correct it. Armed with this information, you can now torrent files, stream geo-unblocked content and browse the internet without looking over your shoulder.




VPN Guides and Best VPN Services

What is VPN and how does it protect you from online threats? Check out all curated resources below.