Virtual Private Networking with the Point-to-Point Tunneling Protocol

Microsoft Corporation

July 16, 1996

Microsoft® Virtual Private Network (VPN) technology, based on the Point-to-Point Tunneling Protocol (PPTP), was created to address secure, low-cost remote access to corporate local area networks (LANs) via the Internet. Point-to-Point-Tunneling Protocol is a new networking technology that supports multiprotocol VPNs. Using PPTP, remote users can employ Microsoft Windows 95® and Windows NT® Workstation or other point-to-point protocol (PPP)-enabled client systems to dial into a local Internet service provider, to connect securely to their corporate network via the Internet. Remote users just dial into the local number of an Internet service provider and securely tunnel into their corporate network.

PPTP can also be used with dense and integrated communications solutions to support V.34 and integrated service digital network (ISDN) dial-up. Corporations can also use a PPTP-enabled VPN over Internet protocol (IP) backbones to outsource dial-up access to their corporate networks in a manner that is cost-effective, hassle-free, protocol-independent, secure, and that requires no changes to their existing network addressing.

Microsoft is a member of the PPTP Forum, a group of leading remote access vendor companies that support PPTP as an open industry standard. The PPTP Forum includes Ascend Communications, 3Com/Primary Access, Telematics, and U.S. Robotics. PPTP is also attracting extensive third-party support.

The companies announced PPTP in March 1996 and published an initial specification. Work on creating implementations was well under way at that time. Since then, good progress has been made, as there are now working implementations of PPTP-enabled products from Microsoft and others. Microsoft included PPTP in Windows NT 4.0 Beta 2 and will include PPTP in the final release of Windows NT Server 4.0 and Windows NT Workstation 4.0. Microsoft also plans to offer PPTP support for Windows 95 clients by year-end 1996.

Work has also moved forward to establish PPTP as an open industry standard. The PPTP specification has been updated and is now available as an Internet Engineering Task Force (IETF) Internet Draft. Sample source code is also now available via the Web in order to make it easier for anyone to begin implementing a PPTP solution on their operating system or hardware platform of choice. In the June IETF meeting in Montreal, the PPTP Forum companies presented PPTP to the IETF’s PPP Extensions working group as an Internet Draft standard. Response was positive—the working group agreed to the proposal made, which will see PPTP and Cisco’s Layer 2 Forwarding approach to tunneling converge in the months ahead.

This is good news for the industry, because there has been no standard in the past—just a variety of proprietary tunneling methods. Movement toward this standard signals an opportunity for remote access system vendors, Internet service providers, and firewall vendors, and it provides great benefit for customers. These groups can also begin to deploy PPTP-enabled systems now with the confidence that Microsoft intends to ensure compatibility with this PPTP standard as it evolves through the IETF in the future.

See the following sources for additional information about PPTP:

PPTP Internet Draft standard:
http://www.microsoft.com/communications/pptpdraft.htm

Original PPTP specification (published 3/96):
ftp://ftp.microsoft.com/developr/drg/PPTP/

PPTP sample source code:
ftp://ftp.microsoft.com/developr/drg/PPTP/src/

PPTP press release:
http://www.microsoft.com/corpinfo/press/1996/mar96/pptppr.htm