Now that we have established the business case for virtual private networks (VPNs) in the company’s communications solutions, it’s time to get into the nuts and bolts of how VPNs work and the various communications solutions VPNs can provide. This chapter will cover the following topics:
An overview of virtual private networking and the VPN technologies supported by Microsoft Windows Server 2003 and Microsoft Windows XP Professional
Basic definitions for VPN technology
A high level overview of tunneling and VPN administration
An overview of Point-to-Point Tunneling Protocol (PPTP) and Layer Two Tunneling Protocol with Internet Protocol Security (L2TP/IPSec), which are the two industry-standard methods for VPN connections
When Microsoft Windows XP is mentioned in this book, we are referring to Windows XP Professional Edition. Windows XP Home Edition does not have the Active Directory directory service and domain authentication features to support VPN.
Likewise, all references to Microsoft Windows NT 4.0 assume the Routing And Remote Access Service (RRAS) feature has been added. This feature was a part of the separately available Networking Add-on Pack.