A CDN (Content Delivery Network) is a common acceleration technology used by modern websites. By caching website content on nodes located around the world, it allows users to access the content from the nearest location. When conducting website analysis, SEO optimization, or security assessments, determining whether a target website uses a CDN is a fundamental yet important skill. Below are several common methods for identifying this.
Method 1: Use an online CDN testing tool
The quickest way is to use a dedicated CDN testing website; simply enter the domain name to run a test with a single click.
- uutool.cn::https://uutool.cn/cdn-check/ — A domestic tool that lets you enter a domain name to check whether a CDN is being used and identify the specific CDN provider
- CDNPlanet::https://www.cdnplanet.com/tools/cdnfinder — An international tool that supports detection of more global CDN providers
in order to apsgo.pcoic.com Taking this domain as an example, a check using CDNPlanet reveals that it uses Alibaba Cloud’s CDN service. Tools like this display important information such as the CDN provider’s name and node distribution, making it very intuitive.
Method 2: Use Ping or Traceroute to Determine
Using in the command line ping maybe tracert(Windows)/ traceroute(Linux/Mac) Commands can also help determine this:
- Abnormally low ping value: If you're in the United States and visiting a Chinese website, but the ping time is only a few dozen milliseconds, it likely means the website is using a CDN, and you're accessing the node closest to you.
- Ping results vary across different locations: UseMulti-Location Ping in Webmaster ToolsCheck to see if IP addresses differ across regions; if so, it’s a good indication that a CDN is being used.
- Traceroute Results: If you see something like this in the trace:
cloudflare.com,akamai.com,alibabacloud.comDomain name nodes, etc., indicate that a CDN is involved in the process.
Method 3: Check the DNS resolution results
Usage nslookup maybe dig Command to view a domain's DNS records:
- CNAME Record: If the domain name resolves to something like
xxx.cloudfront.net,xxx.cdn.dnsv1.commaybexxx.cdn.cloudflare.netThe URL indicates that a CDN is being used - DNS resolution results vary by location: Use a global DNS lookup tool (such as whatsmydns.net). If the resolved IP addresses differ by region, it means Smart DNS or a CDN is configured.
Method 4: Check the HTTP response headers
Use the browser's developer tools (F12) or the command line curl -I Examine the HTTP response headers, paying attention to the following fields:
CF-Cache-Status,CF-Ray— Indicates that the Cloudflare CDN is being usedX-Cache— The value isHITmaybeMISSIndicates that it has been cached by the CDNServer— May display CDN provider information, such asCloudflare,AkamaiGHost等Via,X-CDNCustom headers, etc.
summarize
Each of the four methods above has its own advantages and disadvantages: online tools are the most convenient, ping tests are the most intuitive, DNS resolution is the most accurate, and response headers provide the most detailed information. By combining multiple methods, you can more accurately determine whether a website uses a CDN and identify its specific CDN provider.
English 
Chinese