Windows 2000 Professional supports user authentication, which authenticates a users identity. A users authentication is the basis for granting access to network resources. Within this authentication model, the security system provides two types of authentication:
Interactive logon, by which users confirm their identification to their local computer or network account. When using Windows 2000 Professional in a Windows 2000 Server environment, the network account is an Active Directory account.
Network authentication, by which Windows 2000 confirms the users identification to any network service that the user is attempting to access. To provide this type of authentication, the Windows 2000 security system includes three different authentication mechanisms: Kerberos v5, smart cards, and NTLM for compatibility with other versions of Windows.