IIS is a file and application server for the Internet and for intranets. As part of the FrontPage security triad, IIS mediates authentication communication between FrontPage Server Extensions and Windows NT Server. When an authenticated user requests access to a Web resource, IIS impersonates that user. IIS supports four kinds of authentication. When IIS receives an anonymous request, it impersonates the anonymous account.
Basic authentication is an authentication protocol supported by most Web servers and Web browsers.
Although Basic authentication transmits user names and passwords in easily decoded clear text, it has some advantages over more-secure authentication methods in that it works through a proxy server firewall and ensures that a Web site is accessible to almost any Web browser. You can, however, enable both this method and Basic authentication at the same time. Digest Access authentication is similar to Basic authentication, except that a user s name and password are transmitted in a more-secure format. This method requires Microsoft Internet Explorer 5 on the client computer. The central role of the ACLs access control lists that specify what actions each authenticated user and group are permitted to perform on a file or folder becomes clear when you view FrontPage Server Extensions, Windows NT Server, and IIS Web server as an integrated security system.