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CDN Checker – Find Out Which CDN a Site Uses

Find out whether a domain is served through a CDN, which one, and what gave it away.

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About CDN Checker

Use this CDN checker to confirm your CDN really sits in front of the site after a DNS change, to see which provider a competitor uses, or to understand why visitors in different places reach different IP addresses. Enter a domain and we resolve it through three public resolvers, Cloudflare, AliDNS and Google DNS, recording the CNAME chain and the IP addresses each one returns. For the rest of a competitor's stack, from CMS to analytics, try the Website Technology Detector.

The CNAMEs are matched against more than 40 CDN patterns, each IP address is looked up for its network (ASN), and the site's response headers are read for CDN markers. You get a verdict with the evidence behind it, plus a note on geo-DNS when the resolvers see different addresses. Global CDNs like Cloudflare, Akamai, Fastly and CloudFront are covered, and so are Chinese ones: Alibaba Cloud, Tencent Cloud, Baidu Cloud, Wangsu, ChinaCache, Qiniu, Upyun, Huawei Cloud, Volcengine and Kingsoft Cloud. For all of a domain's records, use DNS Lookup.

How to use CDN Checker

  1. 1
    Enter the domain

    Use the host visitors type, such as www.example.com, since a CDN is often set up only on www.

  2. 2
    Click Check

    We ask three public resolvers, look up the networks and read the headers.

  3. 3
    Read the verdict

    The CDN's name comes with the CNAME, network or header that points to it.

  4. 4
    Compare the resolvers

    Addresses by resolver shows whether different DNS servers get different IPs.

Why use Cubfile for this

  • Three resolvers

    Answers from Cloudflare, AliDNS and Google DNS side by side.

  • 40+ CDN patterns

    CNAME targets matched against known CDN host names.

  • Network and header evidence

    IP networks (ASN) and CDN response headers back up the verdict.

  • Chinese CDNs included

    Alibaba Cloud, Tencent Cloud, Baidu Cloud, Wangsu, Qiniu, Upyun, Huawei Cloud and more.

FAQ

CDN Checker: questions and answers

How does the CDN checker know which CDN a site uses?
From three kinds of evidence, a CNAME that points to a CDN's host name, IP addresses in a CDN's network, and headers such as CF-Ray or EagleId. The provider named most often wins, and the Evidence table lists every clue. To read those headers in full, use the HTTP Header Checker.
Why do the resolvers return different IP addresses?
That's typical of a CDN that sends visitors to a nearby server, known as geo-DNS. Different resolvers can be given different nodes, so the checker points it out rather than treating it as an error.
I use a CDN. Why does it say none was found?
Check the host you entered. A CDN is often set up only for www or a static subdomain, while the bare domain points straight at the server. Some CDNs also leave no CNAME or header trace.
Can it find the real server IP behind a CDN?
No. It shows only the addresses public DNS returns, which belong to the CDN, and it doesn't try to uncover the origin server.
Is this CDN checker free to use?
Yes, with no sign-up and no daily tasks used. The result isn't stored.
Share CDN Checker with a friendIt runs in any browser, and they can try it without signing up.

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