[jolmg]

> nor their server IPs are cloudflare

They are for me, apparently because I'm using cloudflare's DNS service, and cloudflare is returning its own IP when I query for archive.vn's.

  $ dig +short @8.8.8.8 archive.vn 
  5.196.68.232
  $ dig +short @1.1.1.1 archive.vn       
  1.0.0.1
  1.1.1.1

They don't return themselves for all hosts,

  $ dig +short @1.1.1.1 google.com
  172.217.9.14

I wonder by what criteria they intercept, and if this by archive.vn's or cloudflare's initiative.

[function_seven]

This link should answer your questions and give the backstory.

https://news.ycombinator.com/item?id=19828317