... authenticating server) and all VPN client computers. • PPTP can be used by computers running Windows XP, Windows 2000, Windows NT version 4.0, Windows Millennium Edition (ME), Windows 98, and Windows ... Operating System Virtual Private Networking in Windows 2000: An Overview White Paper Abstract This white paper provides an overview of virtual private network (VPN) support in Windows 2000 and ... of an L2TP packet containing user data. Microsoft VPN Overview White Paper 11 Figure 7. Structure of an L2TP packet containing user data In Windows 2000, IPSec Encapsulating Security Payload (ESP)...