Can we detect if a site is on CDN?

Question

Is there a way to detect if a site is on a Content Delivery Network and if yes, can we tell which service are they using?

Answer 1

A method that is achievable from the command line is using the 'host' command, with the -a flag set to see the DNS record e.g.

host -a www.visitbritain.com

Returns:

www.visitbritain.com.   0   IN  CNAME   d18sjq5nyxcof4.cloudfront.net.

Here you can see that the CNAME entry tells us that the site is using cloudfront as the CDN.

Answer 2

Just take a look at the urls of the images (and other media) of the site. Reverse lookup IP's of the hostnames you see there and you will see who own them.