This module provides core authentication capabilities to
    allow or deny access to portions of the web site.
    
Extended authentication providers can be created
    within the configuration file and assigned an alias name.  The alias
    providers can then be referenced through the directives
    
This example checks for passwords in two different text files.
The example below creates two different ldap authentication provider aliases based on the ldap provider. This allows a single authenticated location to be serviced by multiple ldap hosts:
This directive sets the name of the authorization realm for a
    directory. This realm is given to the client so that the user
    knows which username and password to send.
    
For example:
The string provided for the AuthName is what will
    appear in the password dialog provided by most browsers.
From 2.5.0, expression syntax can be used inside the directive to produce the name dynamically.
For example:
This directive selects the type of user authentication for a
    directory. The authentication types available are None,
    Basic (implemented by
    Digest
    (implemented by Form (implemented by 
To implement authentication, you must also use the 
The authentication type None disables authentication.
    When authentication is enabled, it is normally inherited by each
    subsequent configuration section,
    unless a different authentication type is specified.  If no
    authentication is desired for a subsection of an authenticated
    section, the authentication type None may be used;
    in the following example, clients may access the
    /www/docs/public directory without authenticating:
From 2.5.0, expression syntax can be used inside the directive to specify the type dynamically.
<AuthnProviderAlias> and
    </AuthnProviderAlias> are used to enclose a group of
    authentication directives that can be referenced by the alias name
    using one of the directives