You are using a VPN but your ISP can still see every website you visit. This is a DNS leak — one of the most common and overlooked privacy failures.
What Is DNS?
DNS (Domain Name System) converts domain names into IP addresses. Every website visit triggers a DNS query. These queries reveal your full browsing history to whoever handles them.
What Is a DNS Leak?
A DNS leak occurs when your DNS queries bypass your VPN tunnel and go directly to your ISP DNS servers. Your traffic appears encrypted but your destination URLs are still visible to your ISP.
Common Causes
- VPN misconfiguration — DNS traffic not routed inside the VPN tunnel.
- IPv6 leaks — Many VPNs only tunnel IPv4, leaving IPv6 DNS queries exposed.
- WebRTC leaks — Browser WebRTC can expose your real DNS resolver via JavaScript.
Test for DNS Leaks
Use Anonymiz DNS Leak Test — it checks which DNS resolvers handled your requests. If you see your ISP servers instead of your VPN providers, you have a leak.
How to Fix a DNS Leak
- Enable DNS leak protection in your VPN client settings.
- Use a private DNS resolver — set 1.1.1.1 (Cloudflare) or 9.9.9.9 (Quad9) in your router or adapter.
- Enable DNS over HTTPS in Firefox, Chrome or Edge.
- Disable IPv6 if your VPN does not support it.
After fixing, run the DNS Leak Test again to confirm the leak is resolved.
