What are security access levels?

Each virtual directory is set to one of three authentication levels, depending on how restrictive it should be in allowing users to access it. The authentication levels are:

Public - Available to all users. No authentication check is required. This authentication level is used for virtual directories that can be shared with the broadest audience.
User - User name/password authentication required. Users attempting to access this resource must submit a valid user name and password as authentication. This authentication level is used for virtual directories that contain sensitive information or contain server-side scripts.
Administrator - Administrators only. Users attempting to access this resource must submit a valid user name and password, and be listed in the Admin Users group for the Web site. This authentication level provides access to all virtual directories and management tools on the device.