tech

Malaysia started mandating ISPs to redirect DNS queries to local servers

> Would not ISPs be required to block even IPs? 

That would be a way to censor that actually works (but is still circumventable).

> What if there is simply no requests coming back when using the IP you want? Or if you get re-routed to another IP address?

You're right for censorship via ip blocking, that's what it would look like. But they're not doing that, they're only rerouting dns. 

> As far as I know its mere convention and standard software setup that is keeping countries from doing things like that?

You're right the default dns in all modern operating systems makes this sensorship possible. But all modern operating systems you can just configure where to ask for dns instead. It's possible in windows, mac, iphone, android... everywhere. And affords very little tech skills to do.