How to make a page visible only to users with permission to use the administration theme? I have created a basic page which I only want to be viewable by people who have access to the administration theme. 

I have given the page a path of admin/shipping-help but to my surprise the page is visible to anonymous visitors, nor does the page display in the admin theme.

What am I doing wrong?
There are some modules that can help with this: like Content Acess, or Node Access

Node Access
Content Access