Microsoft® Windows® XP Networking and Security Inside Out: Also Covers Windows 2000

Ensuring the Security of Files

Among the most powerful security features of Windows XP and Windows 2000 are those that enable you to restrict access to files and folders, both on the local computer and across network shares. In this section, we look at the sometimes confusing mechanisms you need to master to take advantage of these features.

Using NTFS Permissions

For every object stored on a volume formatted with the NTFS file system, Windows maintains an access control list (ACL). As its name implies, this list defines which users are allowed access to that object—typically a file or folder—and which users are denied access. Individual items in the ACL are called access control entries (ACEs) and are made up of the following information:

• The SID ...