DNS Leak Checker

How to Fix DNS Leaks in Firefox

Firefox offers excellent privacy controls, but DNS leaks can still occur if settings aren't configured correctly. Test with our DNS Leak Checker, then follow these steps.

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Step 1: Enable DNS over HTTPS (DoH)

Go to Settings → Privacy & Security, scroll to the bottom, and under "DNS over HTTPS" select "Max Protection." Choose Cloudflare or NextDNS as your provider.

Step 2: Use about:config for Advanced Control

Type about:config in the address bar. Search for and set these values:

Step 3: Use a VPN with DNS Leak Protection

For the most reliable protection, pair Firefox's settings with a VPN like NordVPN. It routes all DNS queries through encrypted servers, ensuring nothing leaks — even if Firefox's settings are reset.

Step 4: Verify the Fix

Return to our DNS Leak Checker and run a new test. All DNS servers should now match your VPN's location.

Stop leaks for good

A VPN with private DNS on every server, a kill switch and WebRTC protection closes every leak this site tests for.

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