There are no differences between an anonymous intranet site and an anonymous Internet site. But even when you use anonymous access, all activity on a system running IIS determines permissions by user name. Associating a user name with every action is fundamental to NT security. The account is added to the local directory services database on stand-alone systems or to the domain directory services database on primary or backup domain controllers. You modify this account by using User Manager.
Annonymous access is enabled by default.
You set anonymous access by using the Service property sheet for each service. If you provide anonymous access only, no one can use a Windows NT account maliciously. For example, anonymous-only settings prevent anyone from getting access by using the Administrator account or any other account with sufficient permissions to alter your computer. You can use NT user accounts to control access to your entire server or to control access to certain files or directories. When the Anonymous check box on the Service property sheet is cleared, every initial request from a client causes an authentication dialog box to appear.