PPP Extensible Authentication Protocol (EAP)
RFC 2284

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Network Working Group                                          L. Blunk
Request for Comments: 2284                                J. Vollbrecht
Category: Standards Track                           Merit Network, Inc.
                                                             March 1998

              PPP Extensible Authentication Protocol (EAP)

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (1998).  All Rights Reserved.

Abstract

   The Point-to-Point Protocol (PPP) [1] provides a standard method for
   transporting multi-protocol datagrams over point-to-point links.

   PPP also defines an extensible Link Control Protocol, which allows
   negotiation of an Authentication Protocol for authenticating its peer
   before allowing Network Layer protocols to transmit over the link.

   This document defines the PPP Extensible Authentication Protocol.

Table of Contents

   1.     Introduction ..........................................    2
      1.1       Specification of Requirements ...................    2
      1.2       Terminology .....................................    2
   2.     PPP Extensible Authentication Protocol (EAP) ..........    3
      2.1       Configuration Option Format .....................    4
      2.2       Packet Format ...................................    6
         2.2.1  Request and Response ............................    6
         2.2.2  Success and Failure .............................    7
   3.     Initial EAP Request/Response Types ....................    8
      3.1       Identity ........................................    9
      3.2       Notification ....................................   10
      3.3       Nak .............................................   10

Blunk & Vollbrecht          Standards Track                     [Page 1]
RFC 2284                          EAP                         March 1998

      3.4       MD5-Challenge ...................................   11
      3.5       One-Time Password (OTP) .........................   11
      3.6       Generic Token Card ..............................   12
   REFERENCES ...................................................   13
   ACKNOWLEDGEMENTS .............................................   14
   CHAIR'S ADDRESS ..............................................   14
   AUTHORS' ADDRESSES ...........................................   14
   Full Copyright Statement .....................................   15

1.  Introduction

   In order to establish communications over a point-to-point link, each
   end of the PPP link must first send LCP packets to configure the data
   link during Link Establishment phase.  After the link has been
   established, PPP provides for an optional Authentication phase before
   proceeding to the Network-Layer Protocol phase.

   By default, authentication is not mandatory.  If authentication of
   the link is desired, an implementation MUST specify the
   Authentication-Protocol Configuration Option during Link
   Establishment phase.

   These authentication protocols are intended for use primarily by
   hosts and routers that connect to a PPP network server via switched
   circuits or dial-up lines, but might be applied to dedicated links as
   well.  The server can use the identification of the connecting host
   or router in the selection of options for network layer negotiations.

   This document defines the PPP Extensible Authentication Protocol
   (EAP).  The Link Establishment and Authentication phases, and the
   Authentication-Protocol Configuration Option, are defined in The
   Point-to-Point Protocol (PPP) [1].

1.1.  Specification of Requirements

   In this document, several words are used to signify the requirements
   of the specification.  These words are often capitalized.  The key
   words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD",
   "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in this document
   are to be interpreted as described in RFC 2119 [6].

1.2.  Terminology

   This document frequently uses the following terms:

Blunk & Vollbrecht          Standards Track                     [Page 2]
RFC 2284                          EAP                         March 1998

   authenticator
             The end of the link requiring the authentication.  The
             authenticator specifies the authentication protocol to be
             used in the Configure-Request during Link Establishment
             phase.

   peer
             The other end of the point-to-point link; the end which is
             being authenticated by the authenticator.