Where We Need Security in an Intranet

Other than controlling and administering access to the individual machines in an intranet (this is the function of a network operating system), we may want to restrict access to certain intranet-accessible information to only a selected group of users. For example, we may want everybody to be able to access the general Accounting Department web server, but we only want people in the Accounting Department to access a draft annual report which is linked to from the home page.