First of all, I'm new in SalesForce developing.
I've created a developer account and created a VisualForce page that looks up for a contact matching a giving query parameter value. Everything works fine when accessing that VisualForce page.
When opening that page inside a iFrame, the Clickjack protection is triggered.
So, I've created a Site (Develop -> Sites). In that site I could open my VisualForce page. The problem is that no login is requested and, therefore, no contact can be found.
I've tried to configure "Login Settings" but no option to change from "Not Allowed" appears.
Can anyone tell me what I am missing?