Why Are Your DNS Leak Test Results Always Off? Check These Overlooked Settings

Many people have had this experience: the IP clearly shows a foreign location, but once you run a DNS leak test, it reports a DNS leak — or different websites give completely different results.

The first reaction is often to suspect that the testing tool is inaccurate. In reality, 99% of the problems come from configuration issues. If you really want to know whether your connection is leaking, a single DNS leak test is far from enough.

Next, let’s break down why DNS leak tests can appear inaccurate, which settings are actually causing trouble, and how to fix them step by step to make your privacy protection both reliable and effective.

I. First, understand: What is a DNS Leak ?

A DNS leak occurs when your domain name resolution requests do not go through the proxy tunnel, but are instead handled directly by your local network (ISP, router, or system DNS).

The result:

•  Your IP appears to be “overseas”

•  But DNS exposes your real network environment

Many DNS leak testing tools determine whether you are truly anonymous based on this behavior.

II. Browser DNS settings are misconfigured (most common)

1️⃣ Chrome / Edge Secure DNS (DoH)

Most modern browsers enable Secure DNS (DNS over HTTPS) by default, often using Google or Cloudflare directly.

Here’s the problem: your traffic goes through the proxy, but DNS bypasses it and connects directly to public DNS servers. One test later, the DNS leak indicator turns red.

How to fix it:

•  Either disable Secure DNS in the browser

•  Or ensure your proxy software supports and takes over DoH

If this is not addressed, a clean DNS leak test result is almost impossible.

2️⃣ Browser cache or extensions interfering with DNS

Many people overlook one detail: the browser’s own cache or certain extensions can also cause abnormal DNS leak test results.

For example:

•  Browser DNS cache not cleared, causing old resolution records to be reused

•  Ad blockers or security extensions intercept DNS requests in the background

What to do:

•  Clear browser cache, especially DNS cache (in Chrome, enter chrome://net-internals/#dns in the address bar)

•  Temporarily disable extensions that may affect networking, then run the DNS leak test again

•  Re-enable extensions after testing

This small detail is often ignored, but it can directly affect the accuracy of DNS leak tests.

III. System DNS is still local or ISP-provided

Many people configure a proxy but forget about system-level DNS settings, such as:

•  Windows still using 114.114.114.114

•  macOS still automatically obtaining local DNS

•  Router forcibly assigning DNS

In these cases, DNS leaks can occur even if the proxy itself works perfectly.

Recommended actions:

•  Manually set system DNS (such as DNS recommended by your proxy)

•  Or use the proxy’s built-in “DNS leak protection” feature

•  Restart network services before testing to avoid cache issues

IV. IPv6 not disabled, DNS taking a “side route”

This is a subtle but highly impactful issue. Many users have:

•  IPv4 routed through the proxy

•  IPv6 running completely unprotected

Many DNS leak testing tools can detect IPv6 DNS, so one test is enough to expose it. If you don’t need IPv6 for now:

•  Disable IPv6 directly on Windows / macOS

•  Or ensure your proxy explicitly supports IPv6 forwarding

Otherwise, it may seem like the test is “inaccurate,” when in fact IPv6 is causing the issue.

V. Different DNS leak testing websites use different detection logic

To be fair to the tools, there is no unified standard for DNS leak testing on the market:

•  Some test system DNS

•  Some test WebRTC

•  Some combine browser fingerprint detection

•  Some even factor in CDN node behavior

That’s why Tool A may show no leak, while Tool B reports a risk.

The right approach: test multiple tools and check whether your real region or ISP is consistently exposed, rather than stressing over a single result.

VI. Don’t just check DNS — check browser fingerprinting too

One thing many people miss: modern platforms no longer rely on DNS alone.

Even if DNS is clean, your browser fingerprint may still give you away, such as:

•  Timezone mismatch

•  Abnormal language settings

•  WebRTC leaks

•  Canvas / Audio fingerprint anomalies

Recommendation: use a browser fingerprint detection tool. With the ToDetect fingerprint checker, you can quickly review:

•  DNS resolution details

•  IP and environment consistency

•  Browser fingerprint risk points

This helps you pinpoint exactly which layer is causing the problem.

VII. The correct DNS leak test troubleshooting order (recommended)

If DNS leak test results seem inaccurate, follow this sequence:

1. Disable or adjust Secure DNS in the browser

2. Check whether system DNS is locally controlled

3. Disable or properly configure IPv6

4. Clear browser cache and restart the proxy

5. Compare results using multiple DNS leak testing tools

6. Finally, run a full browser fingerprint test

Following these steps usually helps you locate the issue.

Summary

When encountering DNS leaks or inconsistent test results, don’t rush to blame the tools. Focus on checking browser DNS settings, system DNS, IPv6, and potential browser fingerprint issues.

By cross-verifying with DNS leak tests and the ToDetect fingerprint checker, you can clearly identify which layer is causing the problem instead of being misled by test results.

DNS is only one part of privacy protection — browser fingerprinting is just as important. Once these settings are properly aligned, your privacy protection is truly complete, without being repeatedly “tricked” by test results.