Protect mutliple pages in a template folder I made a member area with multiple pages in a member-area template folder.
I d like to protecte all pages in this folder.  

I know the isLoggedIn function to protect a page in a twig template.
http://buildwithcraft.com/docs/templating/craft.session  

{% if craft.session.isLoggedIn %}
    &lt;a href="{{ logoutUrl }}"&gt;Logout&lt;/a&gt;
{% endif %}


But what would be the best way to protect multiple pages ?  

Put the control on _layouts/base or _layouts/site templates?
Note: And above that problem I got an ajax login form (I can make a dedicated login page if it is more simple and no choice)
You pretty much nailed it.  

If you have multiple pages that require an authenticated session, then have all of those pages extend a template that uses something like {% requireLogin %}.