RADIUS Filter Rule Attribute
RFC 4849

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Network Working Group                                         P. Congdon
Request for Comments: 4849                                    M. Sanchez
Category: Standards Track                      ProCurve Networking by HP
                                                                B. Aboba
                                                   Microsoft Corporation
                                                              April 2007

                      RADIUS Filter Rule Attribute

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 IETF Trust (2007).

Abstract

   While RFC 2865 defines the Filter-Id attribute, it requires that the
   Network Access Server (NAS) be pre-populated with the desired
   filters.  However, in situations where the server operator does not
   know which filters have been pre-populated, it is useful to specify
   filter rules explicitly.  This document defines the NAS-Filter-Rule
   attribute within the Remote Authentication Dial In User Service
   (RADIUS).  This attribute is based on the Diameter NAS-Filter-Rule
   Attribute Value Pair (AVP) described in RFC 4005, and the
   IPFilterRule syntax defined in RFC 3588.

Congdon, et al.             Standards Track                     [Page 1]
RFC 4849                 Filter Rule Attribute                April 2007

Table of Contents

   1. Introduction ....................................................2
      1.1. Terminology ................................................2
      1.2. Requirements Language ......................................3
      1.3. Attribute Interpretation ...................................3
   2. NAS-Filter-Rule Attribute .......................................3
   3. Table of Attributes .............................................5
   4. Diameter Considerations .........................................5
   5. IANA Considerations .............................................6
   6. Security Considerations .........................................6
   7. References ......................................................7
      7.1. Normative References .......................................7
      7.2. Informative References .....................................7
   8. Acknowledgments .................................................7

1.  Introduction

   This document defines the NAS-Filter-Rule attribute within the Remote
   Authentication Dial In User Service (RADIUS).  This attribute has the
   same functionality as the Diameter NAS-Filter-Rule AVP (400) defined
   in [RFC4005], Section 6.6, and the same syntax as an IPFilterRule
   defined in [RFC3588], Section 4.3.  This attribute may prove useful
   for provisioning of filter rules.

   While [RFC2865], Section 5.11, defines the Filter-Id attribute (11),
   it requires that the Network Access Server (NAS) be pre-populated
   with the desired filters.  However, in situations where the server
   operator does not know which filters have been pre-populated, it is
   useful to specify filter rules explicitly.

1.1.  Terminology

   This document uses the following terms:

   Network Access Server (NAS)
      A device that provides an access service for a user to a network.

   RADIUS server
      A RADIUS authentication server is an entity that provides an
      authentication service to a NAS.

   RADIUS proxy
      A RADIUS proxy acts as an authentication server to the NAS, and a
      RADIUS client to the RADIUS server.

Congdon, et al.             Standards Track                     [Page 2]
RFC 4849                 Filter Rule Attribute                April 2007

1.2.  Requirements Language

   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 [RFC2119].

1.3.  Attribute Interpretation

   If a NAS conforming to this specification receives an Access-Accept
   packet containing a NAS-Filter-Rule attribute that it cannot apply,
   it MUST act as though it had received an Access-Reject.  [RFC3576]
   requires that a NAS receiving a Change of Authorization Request
   (CoA-Request) reply with a CoA-NAK if the Request contains an
   unsupported attribute.  It is RECOMMENDED that an Error-Cause
   attribute with value set to "Unsupported Attribute" (401) be included
   in the CoA-NAK.  As noted in [RFC3576], authorization changes are
   atomic so that this situation does not result in session termination,
   and the pre-existing configuration remains unchanged.  As a result,
   no accounting packets should be generated because of the CoA-Request.