How does this work? They have an android app. I guess that connects to your router to change your DNS. (which then resolves their IP for some ad hosts). But ho

How does this work? They have an android app. I guess that connects to your router to change your DNS. (which then resolves their IP for some ad hosts). But how does it set their DNS in your router? Is there a standard API for that? Or did they make a scraper-app for lots of routers?