What Is a DNS over HTTPS Availability Check?
This tool makes genuine HTTPS requests directly from your browser to well-known public DNS-over-HTTPS (DoH) resolvers - Cloudflare and Google - and reports whether each one is actually reachable and responding correctly from your current network. DoH encrypts DNS lookups inside regular HTTPS traffic rather than sending them as plain, unencrypted DNS packets, and some networks specifically restrict or block it, which this tool can help you identify with a real, direct test.
How to Use the DNS over HTTPS Availability Check
- Click "Test DoH Resolvers."
- Each resolver is tested with a genuine request, run independently and simultaneously.
- Check whether each shows "Reachable" with a response time, or "Unreachable."
- If one resolver fails but another succeeds, that specific service or address may be blocked rather than DoH traffic generally.
How It Works
This tool sends a real HTTPS GET request directly to each resolver's standard DoH endpoint, requesting
the DNS record for a fixed, harmless test domain, with the appropriate Accept: application/dns-json
header that DoH services expect. A successful, well-formed response confirms the resolver is genuinely
reachable and functioning; a network error or blocked connection is reported as such, timed precisely from
request start to response.
Understanding Your Results
- Both resolvers show "Reachable" - your network allows DNS-over-HTTPS traffic to these specific well-known providers without restriction.
- One resolver reachable, another not - some networks block specific DoH provider addresses individually rather than the DoH protocol broadly; this pinpoints exactly which service is affected.
- Both resolvers unreachable - your network, firewall, or a corporate/school policy may be blocking DNS-over-HTTPS traffic generally, which some administrators do specifically to maintain visibility into DNS queries for security or content filtering purposes.
- Slow response times even when reachable - reflects normal network latency to that specific resolver's servers, which can vary based on your geographic location relative to their infrastructure.
Browser Limitations
This test confirms whether your browser can reach these specific DoH endpoints via a direct HTTPS request - it doesn't tell you whether your browser or operating system is actually configured to use DoH for its regular DNS lookups, which is a separate setting. A network blocking these test requests here would also block your browser's actual DoH-based lookups if it were configured to use them, making this a useful proxy check either way.
Common Mistakes to Avoid
- Assuming an unreachable result means your internet is broken generally - check whether regular websites load fine first; a DoH-specific block can coexist with otherwise normal browsing.
- Testing only one resolver and generalizing - different providers can be blocked independently, so testing both gives a more complete picture.
- Expecting this to change your browser's actual DNS settings - this tool only tests reachability; enabling DoH in your browser is a separate configuration step done in browser settings.
Frequently Asked Questions
What does it mean if DoH is blocked on my network?
Some networks, especially corporate, school, or public networks, intentionally block DNS-over-HTTPS specifically so administrators can continue monitoring and filtering DNS requests for security or content control purposes.
Does this test change my browser's DNS settings?
No, this tool only checks whether the resolvers are reachable; actually enabling DNS-over-HTTPS in your browser requires a separate setting change in your browser's own preferences.
Is my browsing data sent to these DNS resolvers through this test?
Only a fixed, harmless test domain lookup is sent to each resolver - no personal browsing history or other data from your device is included in these requests.
Why test two different resolvers instead of one?
Different DoH providers can be blocked independently by network policies, so testing multiple gives a more complete and reliable picture of what's actually restricted on your network.
Is DNS over HTTPS more private than regular DNS?
Generally yes, since it encrypts DNS queries within regular HTTPS traffic, making them harder for others on the network path to observe compared to traditional unencrypted DNS lookups.
Conclusion
If you're troubleshooting why DoH isn't working in your browser, or just curious whether your current network restricts it, this gives you a direct, real answer for two major providers. For related connectivity checks, see the CDN Connectivity Test.