Anonymous access, the most common public web site access control method, allows anyone to visit public areas of a web site. The user is not challenged for user name or password, but may be tracked by means of cookies and session state.
Anonymous authentication in Windows Server's Internet Information Server maps the request's security context to the Windows user account called IUSR_computername, where computername is the machine name of the server on which IIS is running.
Critical administrative features and private information must be locked down for security reasons and exposed only to users authenticated by Windows or Claims authentication and authorized by security group membership or direct permission assignment. Different authentication providers and schemes may be used in different Zones of a Web Application's Alternate Access Mapping settings.