Here is the list of IP addresses used by Cloudflare:
However, we are seeing some strange behavior from IPv6 addresses starting 2601:. One of our remote offices was accessing our server and instead of the fixed IPv4 address that the office has, we saw 4 IPv6 addresses in our Plesk log. Cloudflare’s list does not include that range.
I can’t think of any other way that our IPv4 address is getting converted to an IPv6 address during its journey to our server…thoughts?