I have a script that resolves the hostname to an IP address, then it checks to see if the IP is tied to a Cloudflare ASN range. But there are many other ways to check:
there is a Firefox plugin called “Cloud Firewall” which can be configured to block Cloudflare sites
without any tools, you can hit F12 in FF or Chromium when visiting a website, and look at the headers. If there is a “CF-Ray” header, then it’s a Cloudflare site.
if you install Tor, then try to visit the website of the CU. If you are blocked or forced through a CAPTCHA, then you are likely on a Cloudflare website if you see “one more step”. It’s best to test with a browser other than tor browser configured to go over tor because those browsers get the worst treatment.
I have a script that resolves the hostname to an IP address, then it checks to see if the IP is tied to a Cloudflare ASN range. But there are many other ways to check: