What Is a DNS Leak? A Plain-English Guide

DNS is the system that turns domain names into IP addresses, and our guide to how DNS actually works walks through a full lookup. When you type a website address, your device asks a DNS resolver where to connect. That request can reveal which domains you are visiting.

A DNS leak happens when those requests go outside the route you expected. For example, you may connect to a VPN but still send DNS requests to your ISP.

Why this matters

HTTPS protects page content, but DNS can still reveal browsing metadata. If your DNS requests leak to your ISP, local network, or workplace network, those parties may see the domains you look up even if websites see your VPN IP address. That channel is one of three covered in what your ISP can actually see.

How to test

Connect your VPN, then check your visible IP address. If it changed, run our Network Leak Check. It reports the IPv4 address, ISP and location a site sees, and whether a public IPv6 address is exposed outside the tunnel. If any of those still point to your provider, the setup may be leaking.

How to fix common leaks

Enable DNS leak protection in your VPN app. Avoid manually configured ISP DNS servers. Restart the browser and VPN after changing settings. Retest on different networks.

Related: open the Network Leak Check and read how to check if your VPN is working.