TestMyLaptop TestMyLaptop

Free DNS Leak Test — Check If Your VPN Is Leaking

Check if your DNS requests are leaking outside your VPN.

Check if your DNS queries are leaking outside your VPN tunnel.

How it works

How to use the DNS leak test

Click Run Test to check whether your DNS queries are leaking. The tool first detects your public IP address using an external service. It then performs a series of DNS lookups through multiple methods to identify which DNS resolver your browser is actually using. If the detected DNS resolver does not match your expected VPN DNS server, your connection may be leaking.

Understanding DNS leaks

What causes a leak

DNS leaks typically happen because your operating system has multiple network interfaces, and DNS queries are sent through the wrong one. Common causes include: IPv6 traffic not being routed through the VPN, Windows Smart Multi-Homed Name Resolution, VPN connection drops without a kill switch, and manually configured DNS servers overriding the VPN's settings.

How to check for leaks

This tool uses two methods to detect your DNS resolver. It compares the resolver's IP address to your public IP — if they belong to the same ISP or network range, your DNS queries are likely not going through your VPN. A truly private setup shows different networks for your public IP and your DNS resolver.

How browser-based DNS detection works

This tool cannot directly read your system's DNS configuration (browsers do not expose that information for security reasons). Instead, it uses indirect methods: timing analysis of requests to different domains, comparing your public IP with DNS resolver IPs from external databases, and checking whether your DNS server is a known public resolver (like Cloudflare's 1.1.1.1, Google's 8.8.8.8, or your ISP's resolver). While not as precise as a desktop application, this gives a strong indication of whether a leak is present.

Related tools

Frequently Asked Questions

What is a DNS leak? expand_more
A DNS leak happens when your device sends DNS queries to your ISP's DNS servers instead of through your VPN's encrypted tunnel, even though your traffic appears to be going through the VPN. This means your ISP can still see which websites you visit, defeating the purpose of using a VPN.
Why does a DNS leak matter for VPN users? expand_more
The whole point of a VPN is to encrypt your traffic and hide your online activity from your ISP. If DNS queries leak outside the VPN tunnel, your ISP logs every domain you visit — they may not see the specific pages, but they know exactly which sites you connect to, which undermines your privacy.
How can I fix a DNS leak? expand_more
Enable the "kill switch" feature in your VPN client (blocks all traffic if the VPN drops), use your VPN provider's own DNS servers instead of your ISP's default, disable IPv6 if your VPN does not support it, and check for WebRTC leaks in your browser settings or with a browser extension.
Can my browser leak DNS queries even without a VPN? expand_more
Yes. Even without a VPN, certain browser features like WebRTC, prefetching ("Predict network actions to improve page load speed"), and opportunistic encryption can leak DNS queries. Modern browsers use DNS-over-HTTPS (DoH) by default in some regions, which encrypts DNS — but this only protects against on-path snooping, not against your ISP if they are the DoH provider.
Does DNS-over-HTTPS (DoH) prevent leaks? expand_more
DoH encrypts your DNS queries so third parties on the network cannot see them, but it does not prevent leaks in the VPN sense — if your VPN is routing traffic normally but DoH is configured to use a different resolver, those queries still leave the VPN tunnel. For full protection, use your VPN provider's DNS servers and disable fallback to other resolvers.