Switch your DNS resolver
If a name doesn't resolve, switching system DNS to a public resolver like Cloudflare 1.1.1.1 or Quad9 9.9.9.9 often produces different results. Configured per-network or system-wide.
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What's Blocked
Tries to reach popular services from your browser and reports which ones respond, are slow, or appear blocked.
| Service | Status | Time |
|---|---|---|
| YouTube | Probing | — |
| Discord | Probing | — |
| Telegram | Probing | — |
| Signal | Probing | — |
| Proton Mail | Probing | — |
| OpenAI | Probing | — |
| GitHub | Probing | — |
| Twitch | Probing | — |
| X (Twitter) | Probing | — |
| Probing | — | |
| Cloudflare | Probing | — |
| Probing | — |
Fires an opaque fetch() to each service from your browser. Success = reachable, network error / timeout = blocked, slow handshake = throttled or distant. This is a quick first check; precise traffic-shape detection comes with Throttling Detector.
What you can do
If a service is reachable the test marks it OK. Slow or blocked entries are the interesting cases. A few common configuration adjustments to consider.
Enable DNS-over-HTTPS in your browser
Browsers can be configured to perform DNS lookups over HTTPS independently of OS DNS. Firefox: Settings → Privacy → DNS over HTTPS. Chrome: chrome://settings/security → Use secure DNS. Affects the browser only; other applications still use system DNS.
Why blocks happen
Three blocking layers stack independently. DNS-level: provider returns NXDOMAIN for blocked hostnames — easiest to bypass with public DNS or DoH. IP-level: BGP/iptables drop traffic to specific IPs — needs alternative routing. DPI-level (TSPU in Russia, GFW in China): traffic-shape filters look at the TLS ClientHello or QUIC handshake and reset the connection mid-stream — needs traffic obfuscation, not just routing. Different providers implement these at different aggressive levels. Beeline and MTS pass more than Rostelecom on the same blocklist. Mobile carriers vary by tower. YouTube's slowness is a special case — not blocked, just throttled by QoS rules that recognize Google CDN ASNs and cap throughput; see the Throttling Detector tool for that diagnosis.
Technical tool for diagnosing the quality of a network connection. Does not provide means of access to information resources whose access is restricted under applicable law.