CDN inspection and cache diagnosis

One request answers two questions: which CDN serves the site and whether its cache configuration is sound. Rankings show who is faster on average; real-world slowness often comes from your own Cache-Control or Vary headers, which switching providers will not fix.

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One request is sent from a single server region. The result reflects the configuration visible from that egress, not latency or cache behavior in other regions.

What this tool can and cannot do

Can do
Identify a CDN from three independent signals: provider headers such as cf-ray, CNAME ownership and whether the A record falls within a published IP range. The tool also diagnoses cache and protocol settings, IPv6 dual-stack and redirect chains, with evidence you can verify.
Cannot do
This is not a multi-region speed test. The request starts from one region, so it cannot measure regional latency differences or replace continuous monitoring.

The signature library covers common providers only. An unknown result is stated explicitly rather than guessed.

Measured rankings →
How strong is the conclusion?
Headers are provider-declared and can be disabled or spoofed. DNS provides independent evidence: a CNAME and provider IP range are harder to fake. When both signals agree, the conclusion is substantially stronger.

CDN checker: identify the CDN behind a website and diagnose caching

Identify a website CDN using response headers, CNAME ownership and published IP ranges, then inspect cache and protocol settings.

What is CDN identification?

CDN identification uses public network signals to determine which content delivery network handled a request. This tool cross-checks provider headers, the DNS CNAME chain and A-record IP ranges, then reports HTTP settings that affect cache reuse.

How does CDN identification work?

Enter a public HTTP or HTTPS URL. The tool sends one real request from a single region and weighs independent evidence.

  1. 01

    Read response headers

    Inspect provider markers such as cf-ray, x-cache and via, together with status, Cache-Control, Vary, Age and compression.

  2. 02

    Trace DNS ownership

    Follow the post-redirect hostname, resolve its CNAME chain and compare A/AAAA records with published provider ranges.

  3. 03

    Cross-check and diagnose

    Compare header and DNS signals, then flag cache, IPv6, HTTP/3, HSTS and redirect issues. Insufficient evidence stays unknown rather than guessed.

CDN identification FAQs

Can the checker identify every CDN?

No. The signature library covers known public signals. When evidence is insufficient or conflicting, the result says so instead of guessing from a single IP.

Why can headers and DNS point to different providers?

A site may use a multi-layer CDN, proxy or security gateway, or disable and customize provider headers. CNAME, IP range and redirect evidence should be read together.

Is CDN identification a speed test?

No. It validates deployment and cache configuration from one region. Use measured rankings or continuous monitoring for regional latency.

Does checking a domain change its DNS or CDN settings?

No. The checker reads public responses and DNS records only; it does not modify your domain, origin or CDN.

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