What is a DNS Leak?
When you use a Virtual Private Network (VPN), your web traffic is encrypted inside a secure tunnel to protect your privacy. However, a DNS Leak occurs when your operating system bypasses the encrypted VPN tunnel and sends domain name queries (`example.com`) directly to your local ISP's DNS servers.
Because DNS queries reveal every website domain you visit, a DNS leak allows your Internet Service Provider, government agencies, or network administrators to monitor your complete browsing history even while your VPN is active.
Why Do DNS Leaks Happen?
- Default Operating System Fallback: Windows and macOS feature multi-homed DNS resolution algorithms (such as Smart Multi-Homed Name Resolution) that send DNS queries across all network interfaces simultaneously.
- IPv6 DNS Leaks: If your VPN only supports IPv4 encryption, unencrypted IPv6 DNS queries automatically leak to your local ISP resolver.
- Manual DNS Misconfiguration: Failing to configure encrypted DNS over HTTPS (DoH) or DNS over TLS (DoT) inside your browser or router.
Step-by-Step Guide: How to Fix DNS Leaks
- Enable Native VPN DNS Protection: Ensure your VPN client has "DNS Leak Protection" and "IPv6 Leak Protection" toggled ON in client settings.
- Configure Encrypted DNS over HTTPS (DoH): In Chrome, Firefox, or Brave, set your secure DNS provider to Cloudflare (`1.1.1.1`) or Quad9 (`9.9.9.9`).
- Flush DNS Cache: Clear local DNS resolution caches via terminal:
ipconfig /flushdns
Run a real-time DNS resolver security audit on our free DNS leak test tool.