This module allows the use of HTTP Basic Authentication to
    restrict access by looking up users in the given providers.
    HTTP Digest Authentication is provided by
    
The On will choose the default provider
    (file). Since the file provider is implemented
    by the 
See 
The value Off clears the provider list and sets it back
    to the default.
Setting the Off allows for both
    authentication and authorization to be passed on to lower level
    modules (as defined in the modules.c files) if there is
    no userID or rule matching the
    supplied userID. If there is a userID and/or rule specified, the usual
    password and access checks will be applied and a failure will give
    an "Authentication Required" reply.
So if a userID appears in the database of more than one module;
    or if a valid 
By default control is not passed on and an unknown userID or rule will result in an "Authentication Required" reply. Not setting it thus keeps the system secure and forces an NCSA compliant behaviour.