1 Introduction

The Point-to-Point Tunneling Protocol (PPTP) is an Internet Engineering Task Force (IETF) standard protocol that allows the Point-to-Point Protocol (PPP) [RFC1661] to be tunneled through an IP network. PPTP does not specify any changes to the PPP protocol, but instead describes a new vehicle for carrying PPP. PPTP uses an enhanced GRE (Generic Routing Encapsulation) [RFC1701] and [RFC1702] mechanism to provide a flow-and-congestion-controlled encapsulated datagram service for carrying PPP packets. For an introduction to PPTP, see [RFC2637] section 1.

The Point-to-Point Tunneling Protocol (PPTP) Profile [MS-PTPT] specifies the profile of PPTP [RFC2637]. In this document, the terms PPTP Access Concentrator (PAC) and server, and the terms PPTP Network Server (PNS) and client are used interchangeably. This document specifies the use of voluntary tunneling where the PPTP tunnel endpoints and the PPP endpoints reside on PAC (as the server) and PNS (as the remote client).

Sections 1.8, 2, and 3 of this specification are normative and can contain the terms MAY, SHOULD, MUST, MUST NOT, and SHOULD NOT as defined in RFC 2119. Sections 1.5 and 1.9 are also normative but cannot contain those terms. All other sections and examples in this specification are informative.