lol yeah such a simple answer that you couldn't even come up with it! and you don't need to block other domain names , putting just http will block ANYTHING with http in it putting .com will block anything with that in it, no need to write out the entire domain. Yeah you're trying to save face .....and yes I do know, far far far more than you. I've actually made tutorials on how to do it, it works, every time. Before you say that I don't know what im talking about ...how about proving that I don't, because if you stopped being so lazy trying to find a ONE BUTTON solution that doesn't exist and actually tried what i said you would have already found the solution .
To do what you want there are only 3 ways
1. either blacklisting words/phrases (or sites themselves which is more time consuming and can change anyway) in the router for the switch
2. disconnecting your router from the internet
3. Set up a different network/hotspot that has no access to the internet
that's it period, there is no other way...but continue to waste YOUR time looking for one....continue to think you know more, continue to insult the people who are smarter than you and continue to think that what YOU think is true...when it isn't, it just makes you come off looking like a dingle-berry noob cherry. Good luck... although there is no cure for stupid, so I'm afraid you're stuck always being the guy looking for solutions and not the one giving them. Im done with you, insect beneath me , not worth anymore time than what i've given.