What is a DNS Leak?

VPNs offer you security and privacy, ensuring that no one (not even your ISP) can see what you’re doing online. But there is a security flaw known as a “DNS leak” that can reveal all of your web activity to your ISP – even if you’re using a VPN! In this short article, we’ll try to answer some common questions about DNS leaks, explaining what they are, how to check for them, and how to avoid them.

What is a DNS Leak?

A DNS leak is a security flaw that occurs when requests are sent to an ISP’s DNS servers even when a VPN is being used to protect users. A VPN is designed to encrypt a user’s internet connection, which keeps their traffic in a private tunnel that hides all of their browsing activity. That means all the user’s internet searches and website visits are hidden from everyone except for their VPN provider.

However, a DNS leak occurs when the user’s DNS requests move outside the encrypted tunnel and become visible to their ISP. As a result, all their browsing activity, including their IP address, location, and web searches, goes through the ISP in the same way it would if they were not using a VPN.

How does a DNS leak work?

The DNS maps domain names to IP addresses. Here’s what happens when you type example.com into your browser. First, the browser will contact a DNS server and request the unique IP address of the site. Then, the DNS server provides the IP address. The browser uses it to connect to the web server hosting example.com. Finally, the server sends the website’s data back to the browser and you can view and interact with the site.

If you use default DNS settings, your ISP or anyone with legal or illegal access to the DNS server can see which websites you want to visit. Ideally, using a VPN helps you keep your DNS requests private. This means your DNS queries are encrypted, pushed through a VPN tunnel, and sent through the VPN service’s DNS servers. Thus, not even your ISP can track your online activities.

However, using a VPN is not 100% safe. Sometimes, VPN servers leak DNS requests. Instead of encrypting DNS queries and routing them through the VPN server, your device sends them to another DNS server. This process is called a DNS leak and can raise privacy issues. Various reasons such as incorrect configuration, or your VPN service lacking its own DNS servers can expose your DNS traffic to third parties.

Why is it dangerous?

DNS leaks can damage your overall online privacy. After all, nobody wants nosy third parties checking in on the sites they’ve visited or files they’ve downloaded. The biggest and most worrying consequences of DNS leaks are:

• Exposed browsing history: Unencrypted DNS requests contain some pertinent information about you, including the sites you’ve checked out and your approximate physical location. This, consequently, undermines the privacy and anonymity provided by VPNs. From marketers to hackers, anyone can use them to profile your online habits.
• ISP tracking: Your ISP may be able to monitor and log your browsing activities if your DNS requests are leaked. This data can reach third parties, including government agencies, and can even contribute to targeted advertising (which means you’ll see more of those annoying invasive ads).
• Vulnerability to cyberattacks: Hackers can exploit DNS leaks to intercept, redirect, or manipulate your DNS request. This potentially leads to phishing attacks or malware infections. Consequently, your personal or financial information may be exposed to unscrupulous entities.

Do you have a DNS leak?

If you have a DNS leak, you probably won’t be able to tell right away. Your VPN will appear to be connected to one of its servers, and nothing will seem to be out of the ordinary. But behind the scenes, your browser is making DNS lookup requests to the ISP’s DNS servers — which means that they can see every move you make online.

The good news is that it’s pretty easy to test for DNS leaks. There are many free, web-based services (for example, dnsleaktest.com and ipleak.net) that will tell you if you have a leaky VPN. To run a test, first connect to your VPN and select one of its VPN servers. Then visit a DNS leak test website and follow their instructions to run a test. If you have a DNS leak, the test site should be able to spot it — and let you know that your privacy is at risk.

How to prevent DNS leaks

There are plenty of reasons why DNS leaks occur and fixing them may not be simple. Below are some common troubleshooting techniques.

• Reset DNS settings. Simply restore everything to the recommended settings on your device.
• Reset VPN DNS settings. Reset your VPN settings to the recommended ones.
• Update OS. Check your device for operating system updates and implement all of them. Updates contain security patches and should always be implemented when they are released.
• Change internet browsers. Your browser could be giving you trouble, so try switching to a different one.
• Connect to a different network. The problem could be connected to your ISP. Try connecting to a different network.
  Configure firewall settings to include DNS requests. Both soft and hard firewalls can be configured to include DNS requests. It’s important only to do this if you are completely comfortable with what you’re doing. Otherwise, reach out to verified support.
• Use a DNS proxy. This approach is a little more technical and involves manual configuration of the firewall or other proxy tools. We advise limiting this approach to users with technical experience.
• Use a different VPN. If you’re using a lower-quality VPN, it may be time to upgrade. Higher-quality VPNs have better DNS protection and tech support.

Conclusion

DNS leaks, a breach in the information shared during internet requests, pose potential security issues for VPN users. Some common reasons leaks occur include using a subpar VPN service, misconfigured VPNs and DNSs, and unauthorized third parties or apps to name a few.

The best way to arm yourself against DNS leaks is to use one of the most secure VPNs available. You should also do regular checks of your system to make sure other issues aren’t causing leaks. Safeguarding your privacy leads to less spam and scams and even reduces your chances of identity theft.