DNS Leak Protection: Are You Really Anonymous?

DNS leaks are one of the most common ways anonymity is compromised. Even if your traffic goes through Tor, a DNS leak can reveal which sites you're visiting to your ISP.

What Is a DNS Leak?

When you visit a website, your computer needs to resolve the domain name to an IP address. A DNS leak occurs when this resolution request bypasses your VPN or Tor tunnel and goes directly to your ISP's DNS server. Your ISP then knows exactly which sites you're visiting.

Testing for Leaks

Visit dnsleaktest.com or browserleaks.com while connected to Tor or VPN. If you see your ISP's DNS servers or your real IP, you have a leak. Tor Browser handles DNS correctly by default, but custom configurations or other applications may leak.

Prevention

Use Tor Browser as-is without modifications. If using Tails or Whonix, DNS leaks are prevented at the OS level. For VPN users: enable the kill switch, configure DNS to use the VPN's DNS servers, and disable IPv6 (which can bypass VPN tunnels). Test after every configuration change.