Your browser tries to reach known ad, tracking, and malicious domains across seven categories. If your DNS blocks them, they fail. See exactly what is and is not getting through.
Works with AdGuard Home, Pi-hole, NextDNS, Cloudflare, and Harbor Privacy. Runs in your browser, and your results are not sent to us.
How it works: your browser tries to open a network connection to each domain. If DNS blocks it, the connection never happens -- that is a pass. Domains span major ad networks, trackers, social widgets, video ad platforms, malware and phishing infrastructure, cryptomining scripts, and adult content -- the same categories AdGuard Home, Pi-hole, and NextDNS filter by default. When a domain is not blocked, your browser really does contact it, as it would on any website that uses it. Your results are never sent anywhere.
A DNS block test checks whether your DNS resolver refuses to resolve known ad, tracker, and malware domains. This page asks your browser to connect to 54 such domains in six categories, plus 10 optional adult-content domains. A blocked connection is a pass. Your block score is the share that failed to load. Last updated October 31, 2026.
| Tool | How it runs | You maintain it | Best for |
|---|---|---|---|
| Pi-hole | Self-hosted on your own device | Yes | Hobbyists with a spare Raspberry Pi |
| AdGuard Home | Self-hosted on your own device | Yes | Self-hosters who want encrypted DNS built in |
| NextDNS, ControlD | Hosted cloud DNS | Configuration only | Technical users who want fine-grained rules |
| Harbor Adblock | Managed hosted DNS, no logs | No | Families who want it set up in about 60 seconds, with a dashboard and parental controls |
A DNS block test checks whether your DNS resolver refuses to resolve known ad, tracker, and malware domains. This test asks your browser to connect to 54 such domains in six categories, plus 10 optional adult-content domains. Each blocked connection counts as a pass, and the result is a block score.
Click Run Block Test. If your DNS blocks a domain, the connection fails and that domain passes. A high score means your DNS blocker is filtering those categories. A low score means ads and trackers are still reaching your devices.
Common causes: your browser uses its own secure DNS (DNS over HTTPS) and bypasses your network DNS, a VPN is routing DNS elsewhere, the device uses a hardcoded DNS server (many smart TVs and consoles do), or your blocklist does not include that domain. Turn off the browser's secure DNS setting or point it at your blocker, then run the test again.
Yes. It works with any DNS-level blocker, including AdGuard Home, Pi-hole, NextDNS, ControlD, Cloudflare Gateway, and Harbor Privacy. It tests the result in your browser, so it does not need to know which blocker you use.
Yes. The test runs entirely in your browser with JavaScript. No results are sent to our server. Any domain your DNS does not block is contacted directly by your browser, the same as on any website that uses it.
Yes. Extensions can also stop these connections, so a pass does not prove your network DNS is blocking. To test DNS only, run the test in a browser or private window with extensions off.
Open source: the domain list and a command-line checker are on GitHub (MIT license).
Related guides: AdGuard Home vs Pi-hole, block ads on all devices, why Pi-hole stops working with browser DoH.