opdeck / cloudflare

Cloudflare Detection

Check if a website is using Cloudflare and its configuration

Detect whether a domain is proxied through Cloudflare by checking nameservers, HTTP headers, and IP ranges.

- Determine if a competitor or partner uses Cloudflare
- Verify your own Cloudflare setup is active
- Check nameserver configuration for Cloudflare domains

Cloudflare is used by over 20% of all websites on the internet to provide DDoS protection, Web Application Firewall (WAF) capabilities, CDN acceleration, and DNS management. Knowing whether a site is behind Cloudflare — or whether your own setup is correctly proxied — is fundamental for infrastructure analysis, security research, and competitive intelligence. It also matters when diagnosing why a site behaves differently from different networks or geographic locations.

The Cloudflare Detection tool performs a multi-signal analysis: it checks the domain's nameservers against Cloudflare's known NS records, inspects HTTP response headers for Cloudflare-specific values (CF-RAY, CF-Cache-Status, Server: cloudflare), and validates the resolved IP address against Cloudflare's published IP ranges. The result tells you definitively whether a domain is proxied through Cloudflare, which is more reliable than any single signal alone — since headers can be spoofed and nameservers can be configured independently of proxy status.

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