Requesting list of IP addresses so we can whitelist them

[AltusMike]

Hello,

Can you please share the list of IP Addresses you use for https://validator.w3.org/unicorn/ ?

The one I could get from the free web tool is - 128.30.52.39.

Please let me know if this one is correct and also send me the list if you use any other IP addresses.

We are building a new website and are using a few security protocols so we need to whitelist the IP addresses you are using.

Your quick response would be appreciated.