How to know a server is anycasted or unicasted?

I see anycast is explained below. Would you please let me know how to
tell whether a server is anycasted or unicasted? Do you have an
example to demonstrate the testing procedure? Thanks.

https://www.cloudflare.com/learning/cdn/glossary/anycast-network

Type in the URL of the site you want to test:
https://www.uptrends.com/tools/cdn-performance-check

Look at the results page. You’ll see the IP address the test connected to. And if you expand that result, you’ll see the Ray ID with the Colocation (airport code) of the server that responded.

If the same IP address responds with multiple airport code locations, then it’s Anycast.

Here is the result page for gmail.com. (remove xxx from the beginning)

xxxhttps://www.uptrends.com/tools/cdn-performance-check?toolRequestGuid=e974edc6-085e-497f-bb3d-664d97dfc715

I don’t see Ray ID with the Colocation. Which response has it? Or I should try a different domain name.

Is gmail.com anycast or unicast? Thanks.

Sorry, my instructions only apply to Cloudflare Anycast.

This is the result for cloudflare.com. Could you show me the Ray ID with the Colocation?

https://www.uptrends.com/tools/cdn-performance-check?toolRequestGuid=6177cd58-85c5-4d3d-8e49-43a9f3488255

Is it anycast or unicast? Thanks.

What are “airport code locations”?

Is CF-Ray only specific to cloudflare websites? What is CF-Ray is for?

So in general there’s nothing unique about an anycast IP address… the question comes down to GRE routing. You’d need to use a tool like Looking Glass and or others to make a determination as to how an Ip range is advertised.

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