DNS Leak Test

A DNS (Domain Name System) leak occurs when your DNS queries are sent to your ISP's default DNS servers instead of through your VPN tunnel, even when you think your VPN is protecting you. When you visit a website, your device must first resolve the domain name (like google.com) to an IP address using a DNS server. If you are using a VPN but your DNS requests still go to your ISP, your ISP can see every website you visit — completely defeating the purpose of the VPN. Our DNS Leak Test detects this vulnerability by checking which DNS servers are resolving your queries and comparing them against known ISP DNS servers.

How DNS Leaks Happen

DNS leaks can occur for several reasons. Many operating systems have a feature called 'Smart Multi-Homed Name Resolution' (Windows) or similar, which sends DNS queries to all available network interfaces simultaneously for faster resolution — this can bypass your VPN tunnel. Poorly configured VPN clients may not properly redirect DNS traffic. Some VPN protocols do not handle DNS routing at all. IPv6 DNS queries can leak even when IPv4 traffic is properly tunneled. Our test helps you identify if any of these issues are affecting your setup so you can take corrective action.

How to Fix DNS Leaks

To fix DNS leaks, start by ensuring your VPN client has built-in DNS leak protection enabled. Switch to a reputable public DNS server like Cloudflare (1.1.1.1) or Google (8.8.8.8) manually in your network settings. On Windows, disable 'Smart Multi-Homed Name Resolution' in Group Policy. Consider using DNS over HTTPS (DoH) or DNS over TLS (DoT) for encrypted DNS queries that cannot be intercepted or redirected by your ISP. Run our DNS Leak Test before and after making changes to verify the fix.