The fix, in one snippet
Firefox:
Settings > Privacy & Security > Website Privacy Preferences >
tick "Tell websites not to sell or share my data"
Brave: On by default, no action needed
Chrome: No built-in setting; use a GPC extensionIllustrative values. Change the paths, hostnames and options to match your own site before using it.
The sections below explain what is tested, why it matters and the alternatives.
What we test
The server records whether the request carried a DNT: 1 header, and the page reads navigator.doNotTrack in JavaScript. We report the state and whether the two agree. This check is informational: a missing Do Not Track signal is not a security weakness, and several browsers no longer offer the option at all. Firefox removed its Do Not Track setting in version 135 (February 2025) in favour of Global Privacy Control, and Safari dropped it in 2019 because the signal had become one more fingerprinting bit. Chrome and Edge still expose the setting.
Why it matters
Do Not Track was a W3C proposal (Tracking Preference Expression) that asked sites to voluntarily stop tracking users who sent the header. No law required compliance, the advertising industry never agreed on what "honouring" meant, and the signal is widely ignored. The only practical effects today are that a small number of sites honour it and that sending an uncommon header makes your browser slightly more distinctive. Global Privacy Control is the successor with legal weight in several US states; see the GPC check.
How to fix it
If you want to send it anyway: Chrome: Settings > Privacy and security > Third-party cookies > "Send a Do Not Track request". Edge: Settings > Privacy, search and services > "Send Do Not Track requests". Firefox 135 and later and Safari no longer offer it. A more effective approach is to enable Global Privacy Control where available and to block trackers with the browser's tracking protection or a content blocker, which does not depend on the site's goodwill. The differences are explained in Do Not Track vs Global Privacy Control and how online tracking works.
Where this fits
Do Not Track signal is check 13 of 16 that the browser security & privacy check runs under browser privacy and policy enforcement, ordered the way they are worth fixing. That ordering is the point: Fixing this one while the check above it still fails buys less than it looks like.
Fix this one first
Above it in the same category sits WebGL renderer exposure (low), where scripts can read your graphics card model and driver details through WebGL, a strong and long-lived identifying signal. An attacker who has that does not need this, so it is the better use of the same hour.
What fixing this still leaves open
Do Not Track signal closes one route in. Immediately below it: Hardware details exposed to scripts, where scripts on any page can read your CPU core count, approximate memory, screen geometry, touch capability and in some browsers battery and network state, all of which feed a fingerprint; JavaScript disabled, where javaScript is off in your browser, so the client-side parts of this scan could not run; User-Agent Client Hints exposure, where your browser answers high-entropy Client Hints requests, revealing its exact version, platform version, device model and CPU architecture to any site that asks.
The first few lines
You are a senior web engineer. I ran a security and SEO scanner against my site and it reported the finding below. Fix it properly rather than suppressing the symptom.
Finding: Do Not Track signal (info severity)
Scanner check id: do-not-track-signal
What this check tests: Your browser is not sending the DNT: 1 header. Most sites ignore the signal in any case, so this is informational.The rest of this prompt names the pages and line numbers we found the problem on, the configuration to change, and the constraints a good answer has to respect. It is free, it just needs an account so the work is not scraped wholesale.
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References
Related guides
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