DNS Leak Test
Check if your DNS queries are leaking outside your VPN tunnel with our free DNS Leak Test. The tool detects your local IP addresses via WebRTC, checks your public IP address and geolocation via free IP services, and attempts to identify your DNS resolver. If your real IP is exposed through WebRTC or your DNS queries are handled by your ISP instead of your VPN provider, a leak is reported with actionable recommendations. Run the test with and without your VPN to verify your privacy setup. No signup required.
Check if your DNS queries are leaking outside your VPN tunnel. This test detects your local IP addresses via WebRTC, checks your public IP address, and attempts to identify your DNS resolver. A mismatch between your VPN IP and your detected DNS servers may indicate a leak. All tests run directly from your browser - no server proxy is used.
Why Use Our DNS Leak Test?
Comprehensive DNS Leak Detection
Our DNS leak test checks three critical areas: WebRTC IP leakage (detects your real IP even behind a VPN), public IP identification (shows your internet-facing IP address), and DNS resolver detection (identifies which DNS servers your system is using). A comprehensive battery of tests to identify privacy leaks.
WebRTC IP Leak Detection
WebRTC can expose your real IP address even when you are connected to a VPN. Our tool creates a STUN connection to detect all local IP addresses exposed through WebRTC. If your real public IP or private IP appears alongside your VPN IP, you have a WebRTC leak that could compromise your privacy.
Public IP & Geolocation Check
Detects your public IP address using free IP geolocation services and displays your approximate location and ISP. Compare your public IP against your WebRTC-detected IPs to identify mismatches that indicate a DNS or IP leak. Run the test with and without VPN to verify your VPN is working correctly.
Private & Browser-Based Testing
All DNS leak tests run directly from your browser. We do not store, log, or process any test results on our servers. WebRTC detection runs locally, IP checks use free public APIs, and your data is never sent to our infrastructure. No signup, no account, no tracking.
Common Use Cases for DNS Leak Test
VPN Privacy Verification
After connecting to your VPN, run our DNS leak test to verify your real IP and DNS queries are not leaking. A proper VPN should route all traffic - including DNS queries - through the encrypted tunnel. If your real ISP's DNS servers appear in the test results, your VPN is leaking DNS queries.
New VPN Provider Evaluation
Before committing to a VPN provider, test their DNS leak protection. Run our DNS leak test while connected to their service. Repeat the test multiple times and check for WebRTC leaks, DNS resolver leaks, and IPv6 leaks. Compare providers to find one with robust leak protection.
Public Wi-Fi Security Check
When connecting to public Wi-Fi (cafés, airports, hotels), run our DNS leak test to ensure your DNS queries are not being intercepted or redirected by the network operator. A secure connection should use encrypted DNS or your VPN's DNS servers, not the public Wi-Fi provider's DNS.
Browser Privacy Configuration Audit
Audit your browser's privacy settings by testing whether WebRTC is exposing your real IP address. Many browsers have WebRTC enabled by default, which can leak your IP even with a VPN. Use our test to verify that WebRTC controls or extensions are working correctly.
Corporate VPN Compliance Testing
Ensure corporate VPN policies are being followed by testing for DNS leaks on company-managed devices. Regular DNS leak testing helps IT teams verify that VPN configurations are correct and that employee connections are properly secured against data exfiltration through DNS.
Activist & Journalist Security Check
For activists, journalists, and anyone working in sensitive environments, a DNS leak can reveal your real location and ISP to adversaries. Run our DNS leak test before engaging in sensitive communications to verify your anonymity tools are working and no identifying information is leaking.
Understanding DNS Leaks
What is a DNS Leak?
A DNS leak occurs when your device sends DNS queries outside your VPN tunnel, revealing which websites you visit to your Internet Service Provider (ISP) or other third parties. Even when connected to a VPN, your operating system or applications may bypass the VPN and use your default DNS servers. This means your ISP can still see every domain you visit - completely defeating the privacy benefits of using a VPN. DNS leaks can happen due to incorrect VPN configuration, IPv6 traffic bypassing the VPN, WebRTC exposing your real IP, or Windows Smart Multi-Homed Name Resolution sending DNS queries to all available DNS servers simultaneously.
How Our DNS Leak Test Works
- WebRTC IP Detection:The tool creates a WebRTC connection using Google's public STUN server. ICE candidates are collected to detect all local IP addresses visible to the browser. This reveals any IP addresses that WebRTC exposes - including your real IP even when behind a VPN.
- Public IP Check: The tool queries multiple free IP geolocation services to identify your public-facing IP address, approximate location, and ISP. This is the IP address the internet sees when you connect to websites.
- DNS Resolver Detection:The tool attempts to identify your DNS resolver by making a DNS query to a special endpoint that returns the resolver's IP address. This reveals which DNS servers are actually handling your queries.
- Analysis: All detected IPs are compared. If your real public IP appears in WebRTC results while connected to a VPN, or if your DNS resolver belongs to your ISP instead of your VPN provider, a leak is reported with actionable recommendations.
Common Causes of DNS Leaks
- IPv6 Leaks: Your VPN may only protect IPv4 traffic. If your device has a IPv6 address and the VPN does not support IPv6, DNS queries sent over IPv6 will bypass the VPN entirely.
- Windows Smart Multi-Homed Name Resolution:Windows sends DNS queries to all available DNS servers simultaneously and uses the fastest response. This means your ISP's DNS server may be used even when a VPN is active.
- WebRTC Leaks: WebRTC can bypass VPN tunnels and expose your real IP address through STUN requests. This is a browser-level issue that affects all major browsers unless WebRTC is explicitly disabled.
- Transparent DNS Proxies:Some ISPs use transparent DNS proxies that intercept all DNS traffic (including traffic to your VPN's DNS servers) and redirect it to their own servers.
- VPN Disconnects: If your VPN disconnects unexpectedly and your device falls back to your default network connection, DNS queries will leak. A kill switch feature prevents this, but not all VPNs include one.
Privacy, Security & Limitations
Our DNS Leak Test runs directly from your browser. WebRTC detection is entirely local - no data is sent to our servers. Public IP detection uses free third-party API services. We do not store, log, or process any test results on our servers. The tool is 100% free with no signup, no account, and no usage limits.
Important limitations:Browser-based DNS leak detection is inherently limited. We cannot directly read your system's DNS configuration or intercept raw DNS queries. WebRTC detection depends on browser support and may not work if WebRTC is disabled. DNS resolver detection relies on third-party DoH services. For a comprehensive DNS leak test, consider using dedicated desktop applications or command-line tools in addition to our browser-based test.
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Frequently Asked Questions About DNS Leak Test
A DNS leak occurs when your device sends DNS queries outside your VPN tunnel, revealing your browsing activity to your Internet Service Provider (ISP) or other third parties. Even when you are connected to a VPN, your operating system or browser may bypass the VPN and use your default DNS servers, allowing your ISP to see which websites you visit despite the VPN connection.
Our DNS leak test checks three things: (1) WebRTC IP detection - creates a STUN connection to detect all local IP addresses exposed through WebRTC, which can reveal your real IP even behind a VPN. (2) Public IP check - queries free IP geolocation services to identify your public IP address, location, and ISP. (3) DNS resolver detection - attempts to identify which DNS servers are handling your queries. All results are analyzed and compared to detect potential leaks.
A DNS leak means your ISP or network operator can see every website you visit, even while connected to a VPN. This defeats the privacy purpose of using a VPN. Your browsing history, the services you use, and potentially sensitive domains you visit are all visible to your ISP. DNS leaks can also expose your real geographical location, which may be a concern for users relying on VPNs for location privacy.
To prevent DNS leaks: (1) Use a VPN that includes built-in DNS leak protection and a kill switch. (2) Configure your VPN to use its own DNS servers. (3) Disable WebRTC in your browser or use a WebRTC-blocking extension. (4) Disable IPv6 if your VPN does not support it. (5) On Windows, disable Smart Multi-Homed Name Resolution. (6) Use encrypted DNS (DNS-over-HTTPS or DNS-over-TLS) as a backup.
A WebRTC leak occurs when the WebRTC (Web Real-Time Communication) API exposes your real IP address even when you are connected to a VPN. WebRTC uses STUN servers to discover your IP address for peer-to-peer connections. Because WebRTC operates at the browser level, it can bypass VPN tunnels and reveal your true IP address. Most browsers have WebRTC enabled by default. Our DNS leak test detects this by creating a STUN connection and collecting all exposed IP addresses.
DNS resolver detection may fail for several reasons: (1) Your browser uses encrypted DNS (DoH/DoT) which prevents detection. (2) Your network blocks DNS-over-HTTPS queries to external services. (3) CORS restrictions prevent the browser from accessing DNS resolution APIs. (4) Your VPN routes DNS through its own encrypted channel. If DNS resolver detection fails, check your system's DNS settings manually or use a dedicated DNS leak test tool.
No. All DNS leak tests run directly from your browser. WebRTC detection is entirely local and does not send data to our servers. Public IP detection uses free third-party API services (ipify.org, ip-api.com, ip.sb). We do not store, log, or process any test results on our servers. To verify this, you can run the test with your browser's developer tools open and observe the network requests.
Yes! Our DNS Leak Test is 100% free with no signup, no account, no API key, and no usage limits. Run the test as many times as you need - with and without your VPN - to verify your privacy setup. All processing happens in your browser or through free public APIs. No server costs are incurred that would need to be passed on to users.