allowed email addresses

edit

I want to restrict access to content only to the users I trust.

In "Access control settings" I set "Allow only reistered users to access the forum". This works as expected, posts are not visible for unregistered users. But I want only the users I trust to be able to access the content, so I set "Require valid email for" to "acces to content". Then I add some "Allowed email addresses" below.

But still, anyone can register and access the content no matter what email address they register with.

Is this a normal behaviour? What is then the purpose of the "Require valid email for" and "Allowed email addresses" options?

Thank you and kind regards,

Roetem