DNS is the system that turns domain names into IP addresses. When you type a website name, your device asks a DNS resolver where that domain points. A DNS leak happens when those requests travel outside the privacy path you expected, such as outside a VPN tunnel.
Why DNS Leaks Matter
Even if a website sees a VPN IP address, DNS requests can still reveal which domains your device is trying to visit. A resolver does not see the full page content, but it can often see domain names. If those requests go to your ISP while you believe you are using a VPN, your setup is not as private as expected.
Common Causes
DNS leaks can be caused by operating system settings, browser secure DNS settings, split tunneling, misconfigured VPN clients, router-level DNS rules, or corporate security tools. Sometimes the browser uses a different DNS provider than the operating system, which can surprise users during testing.
How to Reduce DNS Leak Risk
Use a VPN that provides DNS leak protection, keep the VPN app updated, avoid mixing multiple VPN or proxy tools at the same time, and check whether your browser’s secure DNS settings conflict with your VPN. If privacy is important, test after every major network or VPN configuration change.