Maybe, but there are plenty of easy ways around such filters. This is a war you will never win, and will constantly be fighting an uphill battle on.
So rather than fight it, you should consider embracing it so you can exert some influence. Think about it. When you were his age, if your father came in with a stack of Playboys and wanted to go through them with you, wouldn't you be a LITTLE creeped out?
Hello, I have 2 PC's and my son uses a laptop he connects using a Ethernet Cable, even though he could wirelessly. I have them all go through a Linksys/ Cisco Wired and Wireless Router then into my cable modem, is there a way to block access to a website I don't want him to use ?...Without installing any software or at least on his laptop. I'm hoping to do it through the router or something.