Comment by air3y

Probably the ISPs would be required to block a given list of domains, and they will do it at DNS requests. Porn sites and torrent sharing sites used to be blocked this way. Some ISPs wont even do it properly. A decade or more ago, when these were banned, I could circumvent it by simply moving to using encrypted dns protocol by running dnscrypt. It is rarely implemented with a zeal, unlike chinese GFW reportedly does.