Board Thread:Support Requests - Getting Technical/@comment-5916303-20141010145016

I'm an administrator on couple of wikis and I would like to prevent anonymous users from editing pages, since they do more harm than good on purpose, such examples include inserting nonsense into various pages or removing content from them. I was told that there's a feature that can instantly prevent anonymous users from editing pages, is this true and if it is can anyone tell me how to perform it? Or do I have to make every page on the wiki inaccessible to anon users? 