Disable viewing of posts for guests?

I know this has to be somewhere but I can't find it. I want to disable viewing of posts for guests but instead bring them to the login form. Would this work in the manual Registered-users-only forums. $regUsrForums=array(1,2); and put all the forum ids in there? It says These forums mean, that only registered (and logged correspondly) users can make new topics, new posts and edit their messages here. But nothing about viewing posts?