What is a DNS Leak? – VPN Privacy Risk Explained

What is a DNS leak?

A DNS leak occurs when your DNS requests are sent outside your VPN tunnel – typically to your ISP's DNS servers instead of your VPN provider's servers. Even though your internet traffic is encrypted by the VPN, your DNS queries reveal which websites you are visiting to your ISP.

This defeats one of the main purposes of using a VPN – keeping your browsing activity private from your ISP and network observers.

Without DNS leak (correct)

Your device→ VPN tunnel

DNS query→ VPN DNS server

Your ISP seesOnly VPN connection

PrivacyProtected

With DNS leak (problem)

Your device→ VPN tunnel

DNS query→ ISP DNS server (leak!)

Your ISP seesAll websites you visit

PrivacyCompromised

Common causes of DNS leaks

Windows Smart Multi-Homed DNSWindows sends DNS to all available servers

IPv6 DNS leakVPN only tunnels IPv4, IPv6 DNS leaks

Misconfigured VPNDNS not routed through VPN tunnel

WebRTCBypasses VPN tunnel entirely

Split tunnelingSome apps bypass the VPN

How to fix DNS leaks

Use DNS leak protectionEnable in your VPN client settings

Set manual DNS1.1.1.1 or 8.8.8.8

Use DNS-over-HTTPSEncrypts DNS queries in browser

Disable IPv6If VPN does not support IPv6

Choose a better VPNUse one with built-in DNS leak protection

Test your connection now

DNS Leak Test WebRTC Test Check my IP

Knowledge DNS Leak WebRTC DNS Lookup My IP

DNS leaks – the hidden VPN vulnerability

A DNS leak is one of the most common VPN vulnerabilities. Even with a VPN active, DNS queries can bypass the encrypted tunnel and reach your ISP's DNS servers, revealing every website you visit. DNS leaks can occur due to Windows settings, misconfigured VPNs, IPv6 issues or WebRTC. Always test your VPN with a DNS leak test to ensure your privacy is truly protected.