DNS Leak: The Silent Privacy Killer
Your VPN Might Be Leaking Your Browsing History
You are using a VPN. Your IP appears masked. You feel safe. But behind the scenes, your DNS queries might be routing through your ISP, giving them a complete log of every website you visit. This is a DNS leak, and it is far more common than you think.
What Is DNS?
DNS (Domain Name System) translates domain names like hackmyip.com into IP addresses your computer can connect to. Every website visit starts with a DNS query. Whoever handles your DNS queries can see every domain you access, even if the traffic itself is encrypted.
How DNS Leaks Happen
When you connect to a VPN, all traffic should route through the VPN tunnel, including DNS queries. But several things can go wrong:
Your operating system may have hardcoded DNS servers that bypass the VPN. Smart Multi-Homed Name Resolution on Windows sends DNS queries over all available interfaces simultaneously. Some VPN clients simply fail to override system DNS settings.
Why DNS Leaks Are Dangerous
A DNS leak means your ISP can log every website you visit despite your VPN. In many countries, ISPs are legally required to retain this data. It can be sold to advertisers, handed to law enforcement, or exposed in data breaches. Your VPN becomes security theater.
How to Detect a DNS Leak
Run our DNS Leak Test. It checks which DNS servers are actually handling your queries. If you see your ISP name or a resolver that is not your VPN provider, you have a leak.
How to Fix DNS Leaks
Configure your VPN client to use its own DNS servers. On Windows, disable Smart Multi-Homed Name Resolution. Use DNS over HTTPS (DoH) or DNS over TLS (DoT) for encrypted DNS. Set your system DNS to privacy-focused providers like 1.1.1.1 (Cloudflare) or 9.9.9.9 (Quad9) as a fallback.
Prevention Checklist
Enable your VPN kill switch. Use VPN-provided DNS servers. Disable IPv6 if your VPN does not support it. Test regularly. DNS leaks can appear after system updates, network changes, or VPN client updates. Make the DNS leak test part of your regular security routine. Also check for WebRTC leaks and verify your IP address is properly masked.