What is a DNS Leak?

So you think getting connected to a VPN can keep your privacy all the time? Well, that depends if your VPN service provider can fully protect your device’s DNS queries. That means it should be capable of concealing everything inside the VPN tunnel. If not, then your information will be shared via a DNS leak.

But why should this happen when the point of getting a VPN is to provide you with end-to-end encryption capabilities to ensure that no one can decode your sensitive data at rest or in transit except for your intended recipient?

In this post, we’ll discuss about DNS leaks and what you can do to detect and prevent it.

What is a DNS?

A DNS or Domain Name System is an internet protocol that translates human readable domain names (such as www.google.com) to a machine-readable code or IP address (such as 191.3.4.56) so that computers can recognize the location to be accessed. An  IP address is necessary for devices to communicate with each other. So, if you want to go to the Google website, you don’t have to type in a string of numbers (or the IP address) but only use a domain name instead and still access Google.

The DNS system is compared to a phone book that maps names and numbers. DNS servers are used to translate users’ requests or more known as queries for names into IP addresses so that the access to websites are managed well. 

What is a DNS leak?

Each time you access a webpage, you type in the website address on your web browser’s address bar. This is received by your internet service provider (ISP) as a DNS query in its server and sends back the directions you need—even if you are connected via VPN. Remember that all ISPs maintain a database of DNS names with their IP addresses.

A VPN leak occurs when your device sends your DNS traffic outside the VPN tunnel. This means that the information on your browsing activity does not undergo encryption. It’s just like not using any VPN at all.

Another instance is when your device sends the traffic to a third-party DNS server, so it’s easier for other parties to pry on your activities. 

What causes a DNS leak?

There are many causes why a DNS leak can occur. For instance, your VPN may be incorrectly configured so all traffic is assigned to your ISP’s DNS server before you log in to the VPN. 

Some VPN services (especially the free VPNs) do not have their own DNS servers, which result to constant DNS leaks, or it does not have an Internet Protocol version 6 or IPv6 support, which will likely bring your DNS requests outside the VPN tunnel.

Even worse is when your device has been hacked and your DNS traffic is then redirected outside your VPN tunnel. 

A good rule of thumb therefore is to avoid using your ISP’s default DNS server by using a reliable VPN and to refrain from accessing suspicious websites that can trick you into a hacker’s schemes. 

How can I check if I have a DNS leak?

You can always perform a DNS leak test using online tools such as ExpressVPN’s Leak Test. 

When you visit the link, it will automatically detect if your ISP can track your browsing activity, each app you use, and other information that you send online. In addition, it will identify who runs your DNS servers on every website that you access.

When you connect on ExpressVPN, the page will confirm that no DNS leak is possible.

What can I do to prevent a DNS leak?

There are plenty of ways to prevent a DNS leak.

1. Use a reliable VPN service with a DNS leak prevention feature.

Not all VPN services are equal. For instance, ExpressVPN guarantees its subscribers that all traffic between the device being used and the DNS servers are all encrypted. Each time you access a website, ExpressVPN ensures that no data traffic escapes the security tunnel when returning any webpage to you.

And if you still detect a DNS leak (although this rarely happens), ExpressVPN’s customer support team will be ready to assist you in fixing the issue 24/7.

2. Use an anonymous web browser. 

You may use Tor, Epic or SRWare Iron that rely on anonymous computer network to connect online. This means you can hide your web activities and prevent third-party surveillance parties.

Remember that setting your browser to incognito mode won’t still prevent your ISP from tracking your activity. This will only hide your browsing history from other users on your device. So, it’s still 

3. Avoid using public Wi-Fi.

Whenever you’re in a hotel or at the airport, the free Wi-Fi service can entice you to surf during your stay. However, most public Wi-Fi connections are encrypted and this can be taken advantage of by malicious hackers to acquire all of your data traffic.

If you cannot avoid using public Wi-Fi, use a VPN to make sure that all of your activities are hidden and you remain anonymous.

4. Enable a firewall.

By disabling the DNS, a firewall can keep your information from leaving your device. If you want to only limit your VPN coverage to select sites, make sure to block non-VPN data traffic using your firewall too.

5. Set your VPN to only use your VPN provider’s DNS servers.

At times, your ISP may force to redirect your data traffic to their own servers without informing you. This means that you are forced to use the ISP’s server and start a DNS leak.

The best solution is to check your VPN settings and enable the option to force use the VPN provider’s DNS servers. This will keep your ISP from intercepting your web traffic and redirecting it using a transparent proxy.

Frequently Asked Questions

How can I find out if there’s a DNS leak on my connection?

Use a DNS Leak Test tool such as ExpressVPN’s free service. This will help you identify if there are any issues with your privacy.

How many times should I perform a DNS leak test?

You must do it regularly just like the way you check for device viruses and bugs.

What should I do if there’s a DNS leak?

If you’re subscribed to a VPN service, contact their customer support right away before proceeding with accessing websites. 

Can a VPN ensure full protection against DNS leaks?

Yes but only if you’re using a trusted VPN service such as ExpressVPN. Not all VPN services provide DNS leak protection, so you need to check out this feature first before subscribing.

What’s a VPN that can prevent DNS leaks?

ExpressVPN is a consistent leader when it comes to security compared to other VPNs. It is based on the British Virgin Islands where it is against the law to conduct any form of data retention. Thus, ExpressVPN guarantees its clients that the company does not keep records of users’ activities or connection logs in any way. Many analysts and product reviewers also agree that ExpressVPN is unparalleled when it comes to its strong privacy and security measures, a global presence of servers, and excellent split tunneling capability. 

Ready to use a paid VPN? Try ExpressVPN!

If you want a VPN that offers robust security and geo-spoofing features that you can trust, start making each browsing experience safe and sound by choosing your ExpressVPN plan today. Enjoy the internet with privacy and security!