How to allow anonymous comments on one content type, but not all I would like anonymous visitors to be able to comment on my 'Blog' content type, but only registered users comment on my 'Forum' content type.

It seems that if anonymous users have permission to comment, this applies to all content types with commenting enabled. 

Am I missing a setting somewhere, or would I need to look at hiding/disabling the comment form if content type is 'Forum' and user is anonymous?
Check out the Allow anonymous comments per node type