Documentation
Complete guide to setting up website monitoring with PingZen. API documentation, code examples, and best practices.
ISP/DPI Blocking Detection
PingZen detects when a website is blocked by the Internet Service Provider (ISP) using Deep Packet Inspection (DPI) or DNS poisoning. Blocked sites are genuinely unavailable from Russia but may work from other countries. This is especially relevant for monitoring from Russia, where thousands of websites are filtered by ISPs.
What We Detect
TLS/Connection Errors
Connection reset during handshake, record layer failure, fake certificates — signs of DPI interference with encrypted connections.
DNS Poisoning
Hostname resolves to a known ISP block page IP address instead of the real server.
HTTP Redirect to Block Page
ISP redirects the request to their block page (e.g., warning.rt.ru, blocked.mts.ru).
Block Page Content
Response body contains markers of ISP block pages (e.g., references to rkn.gov.ru, Roskomnadzor).
How It Looks in PingZen
- An "ISP Filter" badge appears on affected check results.
- A warning banner is shown on the monitor detail page with recommendations.
- Alert notifications include an ISP filtering warning with actionable advice.
Recommendations
- Switch to TCP or Ping protocol — these check port availability without HTTP content, bypassing most ISP filters.
- Disable SSL verification (verify_ssl=false) — avoids TLS handshake interference by DPI devices.
- Pause alerts for blocked monitors — prevents alert fatigue from expected blocking.
Supported ISP Detection
PingZen detects blocking by major Russian ISPs:
| ISP | Method |
|---|---|
| Rostelecom | DNS poisoning, block page redirect |
| MTS / MGTS | DNS poisoning, block page redirect |
| Beeline | DNS poisoning, block page |
| MegaFon | Redirect, fake certificate |
| Tele2 | DNS poisoning, block page redirect |
| Dom.ru (ER-Telecom) | DNS + DPI dual blocking |
| TTK | DNS poisoning, block page redirect |
| Yota | Block page redirect |
FAQ
Does PingZen suppress alerts for ISP-blocked sites?
No. PingZen annotates the check result with "ISP Filter" and enriches alert notifications with recommendations, but does not suppress alerts. You can pause alerts manually for specific monitors.
How accurate is ISP blocking detection?
Detection is based on 30+ known block page IPs, 20+ ISP redirect URLs, and 14+ content markers from OONI research. False positives are rare but possible for sites that legitimately use self-signed certificates.
Will this work for non-Russian ISPs?
Currently, the detection patterns are focused on Russian ISPs. The TLS error pattern detection may catch some DPI interference from other countries, but block page detection is Russia-specific.
Common Questions
What protocols can I monitor?
PingZen supports 23 protocols: HTTP/HTTPS, WebSocket (WS/WSS), TCP, UDP, ICMP Ping, gRPC, DNS, WHOIS, SSL certificates, Email (SMTP/IMAP/POP3), FTP/FTPS, DNSBL, PageSpeed, SOCKS5, MTProxy, API Check, and Transaction. You can monitor websites, APIs, servers, databases, and any network service.
How fast can I get alerts?
Telegram alerts are delivered within 1-2 seconds of detection. Slack and Discord notifications arrive almost instantly. You can configure multiple alert channels for redundancy.
Can I organize monitors by project?
Yes! PingZen supports workspaces, which let you organize monitors by project, environment, or team. Each workspace can have its own alert configurations and team members.
Is there an API for automation?
Absolutely. PingZen provides a full REST API with OpenAPI documentation. You can create, update, and delete monitors programmatically.
How do status pages work?
Status pages are public, branded pages showing your services' uptime. You can display real-time status and allow customers to subscribe for updates.
What happens if I reach my monitor limit?
We'll notify you when approaching your limit. You can pause some monitors or contact us for increased capacity. We never stop monitoring without warning, ensuring your critical services stay protected.
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