DNS leak protection: how to stop DNS leaks

Due to rising cybersecurity concerns, many have opted to shield themselves online with a VPN. However, these tools aren’t 100% foolproof, and some of your queries whenever you’re browsing online might go straight to your ISP when they’re not supposed to. Hence, a DNS leak occurs. But how does it all work? And how to prevent DNS leaks from happening? Let’s dig in.

• What is a DNS leak?
• Why is a DNS leak dangerous?
• How to prevent DNS leaks
• How to identify DNS leaks
• What are the differences between DNS and Smart DNS?

What is a DNS, and how does it work?

DNS (Domain Name System) refers to the mapping of a website’s domain name to an IP address. Since IPs consist of random numbers (or letters), it would be hard for anyone to remember every single page’s IP address. DNS makes it easier for us humans by translating the domain name into the IP address.

So, you can type in “youtube.com” instead of the IP, and you’ll reach YouTube’s website all the same. Your browser sends a request to the DNS server via your ISP to get YT’s IP address. Then, the DNS server checks its cache and sends back the corresponding IP for YouTube.

The problem here regarding privacy is that your Internet Service Provider sees everything you’re trying to access on the web. One can hide their browsing escapades with a VPN. This software encrypts all the traffic transmitted between your browser and the DNS server, making it invisible. Furthermore, your DNS queries go to the VPN’s DNS server, making them unreadable to anyone.

Sometimes, this fails, though, and the queries get sent through your ISP to the default DNS. And that’s what we call a DNS leak.

What is DNS leak?

A DNS leak is when your queries are sent to the DNS server outside the encrypted VPN tunnel, exposing your data. It means that your actual IP address, general whereabouts, and search queries get transmitted to your ISP like they usually would be if a VPN weren’t involved.

Unfortunately, services from various VPN networks are prone to DNS leakage due to several reasons:

• Improper VPN configurations, especially if you’re switching between multiple internet networks
• The VPN doesn’t have a DNS server of its own
• Lack of IPv6 support
• Transparent DNS proxies imposed by some ISPs redirect your searches to their DNS servers despite the VPN being enabled
• The Windows Smart Multi-Homed Name Resolution (SMHNR) feature submits DNS queries to any available server and accepts any DNS server that responds first
• The Windows Teredo feature that sometimes overrides the secure VPN tunnel when transitioning from IPv4 to IPV6

A DNS leak can occur quickly without you ever knowing about it unless you decide to test for such a thing.

Why is a DNS leak dangerous?

DNS leaks expose your data, which includes not only what you’re doing online but your IP address as well. And while your ISP could already see all this information beforehand, it also leaves it visible to other third parties with access to the ISP’s servers.

Any outsider with the right set of tools can partake in unsavory activities with the info they gleam from your internet activities. Cybercriminals can:

• Find out your geographical location via your IP. Pair that with all the stuff you search and post online, and it’s quite easy to pinpoint someone’s exact residential address. Someone might decide to stalk you or even try to rob your home while you’re away.
• Gather private information. Some use IP spoofing and phishing to trick service providers into revealing their clients’ sensitive data.
• Sell your information to third parties. From online advertising companies to bad actors on the dark web, the damage here depends on what the hacker does. While getting more personalized ads isn’t the end of the world, having your personal details (and login information) leaked online could lead you to getting blackmailed or even hacked.
• Hit you with a DDoS attack. A Distributed Denial-of-Service attack essentially disconnects you from the internet by overwhelming the network with a flood of traffic.
• Hack your devices. An IP address contains thousands of ports, and a cybercriminal can quickly brute-force certain ports or exploit open ones. It’s the easiest way for these bad actors to gain unauthorized access to your devices. Some even go as far as to infect them with malware for extra damage.
• Frame you. Yes, a hacker could even go as far as to use your IP address to conduct illegal activities. They can even launch other cyber attacks by taking advantage of your compromised devices.

How to prevent DNS leaks

Once you know how and when a DNS leak might happen, preventing them from occurring is easy. Besides using appropriate tools, doing some tweaking on your part is also necessary.

Use robust VPNs with leak protection

Nowadays, premium VPN providers implement special anti-leak measures that reduce the chance of DNS exposure to almost zero. Specifically, they utilize IP, DNS, and WebRTC leak protection to cover users on all fronts, preventing any encrypted data from slipping through potential cracks.

Another key feature is VPN DNS servers. Many reputable services allow you to change your default DNS server to the one provided by the VPN, ensuring total privacy and untraceability. Doing so also greatly helps with getting better browsing speed, filtering out malicious websites, and accessing blocked websites.

We also can’t stress enough the importance of VPN software. Subscribing to a reliable provider ensures no one can snoop on your online activities or target you. And a proper one will have all the necessary features to prevent any leaks from happening, even in case of VPN failure.

Turn off SMHNR

While the Windows Smart Multi-Homed Name Resolution feature improves browsing performance, it naturally leads to leakage issues when a VPN is in the picture. Because it sends DNS requests to all available servers and networks, all of them receive your information. And it sometimes bypasses the VPN connection when doing so.

Windows 10 users can disable it via the Group Policy Editor. Access it by following these steps:

1. Press the Windows key on your keyboard, type in gpedit.msc, and press Enter
2. Select Computer Configuration > Administrative Templates > Network > DNS Client > Turn off smart multi-homed name resolution
3. Enable the policy, and this will turn off SMHNR

Disable Teredo

Teredo is a Windows-based technology that allows communication of IPv4 and IPv6 protocols. Moreover, it’s a tunneling protocol that is sometimes prioritized over the VPN connection by the system, leading to DNS leaks.

Hence, you should disable Teredo. To deactivate it, follow the instructions below:

1. Open up the command prompt, enter netsh interface teredo set state disabled, and press Enter
2. Type netsh interface teredo show state and press Enter to check if Toredo was disabled successfully
3. Close the command prompt, and that’s it

Clear the DNS cache

Flushing your DNS cache is also recommended since it stores all browsing information. Better yet if you do it regularly. Here’s how to clear the DNS cache on Windows:

1. Open the command prompt, enter ipconfig /flushdns, and press the Enter key
2. You should see the message “Successfully flushed the DNS Resolver Cache,” it means the cache was cleared
3. You can check whether the DNS cache was flushed properly by typing in ipconfig /displaydns and pressing Enter

Change DNS settings

Enforcing a good DNS service is also crucial. You can check out TCP/IPv4 options within the properties of your network adapters. Here, set OpenDNS or whichever DNS service you prefer for all available network adapters. Enforcing another DNS ensures that your internet provider’s DNS servers are not used.

1. Go to Settings > Network & Internet > Status
   
   
2. Scroll down until you find Advanced network settings and press Change adapter options
   
   
3. Right-click on your network and select Properties
   
   
4. Select Choose Internet Protocol Version 4 (IPv4) and press on Properties
   
   
5. Check Use the following DNS server addresses and enter the new DNS server addresses
6. Click OK and then repeat the same steps for Internet Protocol Version 6 (IPv6)

Best VPNs to prevent DNS leaks

Our team tested 30 secure VPNs to find out which ensure total protection and aren’t prone to any leaks. We paid close attention to the robustness of the security toolkit, what kind of additional features are offered, performance, price, and such.

1. NordVPN – the most secure VPN

NordVPN is the safest VPN with powerful leak protection. Besides that, this service ensures your traffic is invisible to snoopers with AES-256 encryption and 2 reactive kill switches. Moreover, the provider operates from privacy-friendly Panama, adheres to a thrice-audited no-logs policy, and even had its apps audited for any security holes (none were found).

With NordVPN, you can pick from specialized servers suited for different online tasks. Double VPN encrypts your connection twice, Onion over VPN routes the traffic via the Tor Network for improved anonymity, and obfuscated servers effectively bypass internet censorship. And the whole server fleet runs solely on RAM modules, making data logging impossible.

Feature-wise, there’s plenty to pick from as well. NordVPN offers Threat Protection for blocking ads, user trackers, and malicious websites. Split tunneling lets you pick which apps work only with the VPN connection and which don’t. Finally, there’s Dark Web Monitoring which scans the web for data leaks.

Best of all, NordVPN is highly affordable, coming with a 74% discount. And you can try several discount coupons to get a better deal. A 30-day money-back guarantee is also available if you change your mind after testing it out.

For a deeper investigation of NordVPN, read our NordVPN review.

2. Surfshark VPN – safe VPN with unlimited connections

Another secure VPN with top-notch leak protection is Surfshark. It has all the essential security features, along with DNS, IPv6, and WebRTC leak prevention. As expected of a premium service, it also passed multiple security audits, a no-logs policy audit included, and utilizes a RAM-only server fleet for maximum user privacy.

Surfshark VPN stands out due to the sheer abundance of features. For example, NoBorders and Camouflage modes tackle Deep Packet Inspection (DPI), while CleanWeb takes down malware and trackers and prevents you from entering suspicious websites. Bypasser lets you customize VPN traffic, while MultiHop routes it via two VPN servers. Can’t forget about Rotating IP that periodically changes your IP without dropping the secure connection.

Then there’s Surfshark One, which costs extra. It’s an add-on that deals with other cybersecurity concerns. The package includes an antivirus, a private web browser, ID leak protection, and a proxy email that lets you generate an alternative ID.

You can benefit from superb protection with Surfshark today for a 86% smaller price tag. Of course, we also recommend perusing the available coupons. And last but not least, you commit knowing subscriptions are risk-free, thanks to the 30-day money-back guarantee.

For a deeper investigation of Surfshark VPN, read our Surfshark VPN review.

How to set up a VPN to prevent DNS leaks

1. Subscribe to a reliable VPN with leak protection. Our top choice is NordVPN, now 74% off
2. Install the VPN application on your device
3. Go to the settings and enable the kill switch
4. Additionally, enable DNS, IPv6, and WebRTC leak protection if these are disabled
5. Change your DNS server to the VPN’s DNS server. NordVPN allows doing this in the app.
6. And that’s it. All that’s left to do is connect to a server, and your VPN connection will be foolproof of any leaks.

No DNS leaks with NordVPN

How to identify DNS leaks

Performing a DNS leak check is relatively straightforward: You can visit a site such as dnsleaktest.com and run the DNS leak test. What’s more, many VPN services comprise solutions that monitor the DNS requests to make sure that they are routed through the VPN and not your ISP’s DNS server.

First, run a DNS check when you’re not connected to the VPN to see your naked information. It should include such things as your ISP IP address, ISP name, hostname, and geographical location (sometimes even a city). Write it down on a note.

Next, enable the VPN by connecting to any other geographical location. When you perform a DNS leak test now, you should get completely different information corresponding to your chosen VPN server. If any of the data displayed matches your actual info, a data leak is occurring.

DNS leaks explained: video

What are the differences between DNS and Smart DNS?

DNS is simply the way computers communicate with the internet to fetch you the right website. People tend to use ISP-provided DNS servers by default. However, it’s possible to change them to alternative ones, helping improve privacy, performance, and access to blocked pages.

A Smart DNS is the combination of a DNS server and a proxy and is particularly useful for bypassing geo-blocked pages. You’re still accessing a DNS server to complete the search requests, however, the traffic is additionally routed through a proxy server. And since proxies cloak you with an IP address with different geographical coordinates, they let you access restricted foreign content.

In fact, a bunch of streaming-focused VPNs tend to include Smart DNS technology as it helps bypass streaming platform restrictions. It’s especially helpful if you have a streaming device that doesn’t natively support VPN software.

Conclusion

While VPNs are valuable tools for keeping yourself anonymous online, they aren’t exactly perfect. Outside interference and incorrect configurations could end up messing up the VPN connection. And one of the consequences is getting DNS leaks.

However, picking the right VPN with robust leak protection measures is one part of the job. If you want zero chance of any leaks occurring, you should also take the extra step and tweak some system settings as well. Turning off SMHNR, disabling Teredo, and clearing your DNS cache regularly can do wonders.

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You may also like to read:
What is IP spoofing
How to hide your IP address
What is a VPN kill switch
What is a VPN firewall
What is AES encryption
What is split tunneling

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FAQ

How can I check if my VPN is protecting me?

There are several ways to check whether your VPN is working. We recommend testing for IP, DNS, and WebRTC leaks. Before you do so, note your information without the VPN enabled.

How does NordVPN prevent DNS leaks?

NordVPN prevents DNS leaks by routing your information to their own DNS servers via the VPN tunnel. Furthermore, this provider implements robust DNS leak protection, lowering the chances of such a thing occurring to almost zero.

How can I prevent DNS leaks?

You can prevent DNS leaks by using a reliable VPN service with proper leak protection. Additionally, you should change your default DNS server and disable both Teredo and SMHNR since they can intervene with the secure VPN connection.

What is a DNS leak protection VPN?

It’s a VPN that includes strict DNS leak protection measures. Such services take extra steps to ensure that your DNS queries aren’t accidentally exposed to your ISP and other snoopers.