htaccess is a system for handling access control to your pages. It works by placing an .htaccess file in a directory, which contains the access control lists for that directory. It is possible to get fine grained security and to configure exactly who can view which pages. The .htaccess support module must be enabled for htaccess to work.

It is possible to distinguish users either by the IP address or domain name of their computer or by letting them authenticate with a user name and password. The user name and password is by default compared via an authentication module. That usually means that users are authenticated by the operating systems authentication system.

If you want to have password protected pages usable by users that are not handled by the current Authentication module you can create your own database of users by creating .htpasswd and .htgroup files.

htaccess is a standard supported by many web servers. The access control you have built with htaccess should therefore be portable to other web servers.