This article is incomplete and was first written in June 2006 for the BeezNest technical website (http://glasnost.beeznest.org/articles/337).
To require authentication of parts of a webserver using PAM and Apache. That way, you can require a user or users of a group to enter a valid username and password to access some parts of your website using PAM, the default authentication infrastructure on most Unices.
To do this, you need first to install the appropriate PAM authentication module for Apache. For Apache 2.x on Debian (starting from Sarge), this is located in the package libapache2-mod-auth-pam.
You need then to add something similar to the definition of you virtual host and reload your Apache daemon:
<Directory /var/www/myrestrictedarea> AuthType Basic AuthName "Restricted area for My Server" AuthPAM_Enabled On Require group mygroup </Directory>