How to find out the vk.com subnet?

Question

Domain Name System

I want to block the Facebook social network on the router, how to find out the entire subnet that is allocated to it.
nslookup facebookcom выдает


Correctly I understand that it is enough to block only the address 66.220.156.68.

And what about the case with vk.com where the answer is

Answer 1

Through any whois service. You type in an IP address there from the list returned by nslookup and it returns you to whom this address belongs, as well as information about which subnet is issued (including this address) to this friend. You block this subnet. True, large offices (such as vk.com) have whole packs of subnets, in addition, many use clouds.
Here you need to go the other way - you put a proxy and block the domain name on it.

Answer 2

https://vk.com/help.php?page=peering

Answer 3

Sites on the Internet do not have "subnets", they have IP addresses issued to them, which may or may not be in the same CIDR addressing range.

Answer 4

Or maybe turn *.facebook.com on the local DNS server to a page with the inscription "not allowed" and not bother?