Glossary

DNS Leak: What It Is and How It Compromises Your Privacy

Q: How can I test if my VPN has a DNS leak?

You can test for DNS leaks by visiting DNS leak testing websites while connected to your VPN. These tools will show which DNS servers are processing your requests - if you see your ISP's DNS servers instead of your VPN provider's servers, you have a leak.

Q: What causes DNS leaks to happen?

DNS leaks are typically caused by misconfigured network settings, IPv6 compatibility issues, VPN connection drops, or operating system features that send DNS queries to multiple servers simultaneously, bypassing the VPN tunnel.

Q: Can DNS leaks expose all my internet activity?

DNS leaks reveal which domain names you're visiting to your ISP, but they don't expose the full content of your browsing or the specific pages you visit. However, this information can still create a detailed profile of your online interests and activities.

Q: Do all VPN providers protect against DNS leaks?

Not all VPN providers offer comprehensive DNS leak protection. Quality VPN services typically include built-in DNS leak prevention, secure DNS servers, and kill switches, while budget or free VPNs may lack these essential privacy features.

A DNS leak occurs when your device bypasses the VPN tunnel and sends DNS queries through your ISP, exposing your browsing activity.

Details

A DNS leak is a privacy vulnerability that occurs when your device sends Domain Name System (DNS) queries outside of your VPN tunnel, directly through your internet service provider. This happens when your operating system or applications bypass the VPN connection and use default DNS servers instead of the VPN's secure DNS servers. As a result, your ISP can see which websites you're visiting, even though your traffic appears to be encrypted through the VPN.

DNS leaks commonly occur due to misconfigured network settings, IPv6 connectivity issues, or when your VPN connection temporarily drops. Windows systems are particularly prone to DNS leaks because of features like Smart Multi-Homed Name Resolution, which can send DNS requests to multiple servers simultaneously. Mobile devices may also experience DNS leaks when switching between WiFi and cellular networks, as the system might revert to default DNS settings during the transition.

To prevent DNS leaks, choose a VPN provider that offers built-in DNS leak protection and uses secure DNS servers. Many quality VPN services include automatic DNS leak prevention features and kill switches that block internet traffic if the VPN connection fails. You can test for DNS leaks using online tools that show which DNS servers are handling your queries - if you see your ISP's DNS servers instead of your VPN provider's servers, you have a leak that needs to be addressed.