tools / cdn-check
CDN Checker/
Enter a URL to find which CDN the site uses. The verdict comes with its evidence: the DNS CNAME, the site’s response headers and the IP’s network.
You can paste a full URL. This site’s server looks up DNS, then visits the site’s homepage once to read the response headers.
Verdict
CNAME
No CNAME: the domain resolves straight to an IP.
IP address
| IP | Network |
|---|
Website response
FAQ
How can I tell which CDN a website uses?
Two kinds of signs matter. One is where the domain’s CNAME points, for example xxx.cloudfront.net. The other is whether the site’s response carries a header specific to a CDN, such as Cloudflare’s cf-ray. The IP’s network counts as evidence only when the whole network belongs to a CDN company (for example Cloudflare’s AS13335). Networks of cloud providers such as Amazon, Google and Microsoft also host ordinary servers, so they are listed for reference only. Under each CDN you can see which rule matched.
Why are two CDNs shown at once?
Some sites stack two layers, for example Cloudflare in front and CloudFront behind it as the origin. The site may also have just switched CDN, so DNS and the response headers don’t match yet. The evidence for each one is listed separately, so you can tell which is in front: the response headers come from the layer closest to you.
If no CDN is found, does the site not use one?
Not necessarily. The tool currently recognizes 21 providers, including Cloudflare, CloudFront, Akamai, Fastly, Alibaba Cloud, Tencent Cloud EdgeOne and Huawei Cloud, and some CDNs leave no trace in the response. Many sites only put static files such as images and scripts on a CDN, under a separate domain like static.example.com or img.example.com. Try checking that domain too.
Why does it say the website was not visited?
This site’s server only visits websites that resolve to a public IPv4 address. If a domain resolves to a private, local or reserved address, it is not visited, for safety. If it has only IPv6 addresses, the server has no IPv6 and can’t reach it. In both cases the result is based on DNS alone, and the same applies when the site times out or refuses the connection.
Why does the CDN or node differ from what I see on my machine?
A CDN assigns nodes by the visitor’s region, and DNS answers can differ by region too. Here DNS is queried through Google Public DNS and the site is visited from this site’s server in Singapore, so the result shows what is seen from there. Some sites use different CDNs in different countries, for example Alibaba Cloud in mainland China and Cloudflare elsewhere.
What if the homepage redirects to another domain?
Redirects are not followed; only the headers of the first response are read. If the homepage redirects to another domain, for example from example.com to www.example.com, the result shows the redirect target. Click “Check this domain” to check it.
Can it find a website’s real origin IP?
No. For a site behind a CDN, DNS returns the IP of a CDN node and the origin stays hidden behind it. This tool doesn’t try to find the origin either.
Are my lookups logged?
No. The domain goes through this site’s server to Google Public DNS, then the server visits the site’s homepage once as xmmtools, reading only the response headers and not the page content. This site doesn’t log the domains you check, and your browser keeps no history of them.