Client Identifier Option in DHCP Server Replies
RFC 6842

Document Type RFC - Proposed Standard (January 2013; No errata)
Updates RFC 2131
Last updated 2013-02-12
Stream IETF
Formats plain text pdf html
Stream WG state WG Document
Consensus Unknown
Document shepherd No shepherd assigned
IESG IESG state RFC 6842 (Proposed Standard)
Telechat date
Responsible AD Ralph Droms
IESG note Ted Lemon (Ted.Lemon@nominum.com) is the Document Shepherd.
Send notices to dhc-chairs@ietf.org, draft-ietf-dhc-client-id@ietf.org
Internet Engineering Task Force (IETF)                          N. Swamy
Request for Comments: 6842                                 Samsung India
Updates: 2131                                                G. Halwasia
Category: Standards Track                                    P. Jhingran
ISSN: 2070-1721                                            Cisco Systems
                                                            January 2013

            Client Identifier Option in DHCP Server Replies

Abstract

   This document updates RFC 2131 "Dynamic Host Configuration Protocol"
   by addressing the issues arising from that document's specification
   that the server MUST NOT return the 'client identifier' option to the
   client.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6842.

Copyright Notice

   Copyright (c) 2013 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Swamy, et al.                Standards Track                    [Page 1]
RFC 6842                Client Identifier Option            January 2013

Table of Contents

   1. Introduction ....................................................2
      1.1. Requirements Language ......................................2
   2. Problem Statement ...............................................2
   3. Modification to RFC 2131 ........................................3
   4. Security Considerations .........................................4
   5. Acknowledgments .................................................4
   6. Normative References ............................................4

1.  Introduction

   The Dynamic Host Configuration Protocol (DHCP) defined in [RFC2131]
   provides configuration parameters to hosts on an IP-based network.
   DHCP is built on a client-server model, where designated DHCP servers
   allocate network addresses and deliver configuration parameters to
   dynamically configured hosts.

   The changes to [RFC2131] defined in this document clarify the use of
   the 'client identifier' option by the DHCP servers.  The
   clarification addresses the issues (as mentioned in Problem
   Statement) arising out of the point specified by [RFC2131] that the
   server MUST NOT return the 'client identifier' option to the client.

1.1.  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].

2.  Problem Statement

   [RFC2131] specifies that a combination of 'client identifier' or
   'chaddr' and assigned network address constitute a unique identifier
   for the client's lease and are used by both the client and server to
   identify a lease referred in any DHCP messages.  [RFC2131] also
   specifies that the server MUST NOT return the 'client identifier'
   option in DHCPOFFER and DHCPACK messages.  Furthermore, DHCP relay
   agents and servers implementing [RFC2131] MAY drop the DHCP packets
   in the absence of both the 'client identifier' and 'chaddr' option.

   In some cases, a client may not have a valid hardware address to
   populate the 'chaddr' field and may set the field to all zeroes.  One
   such example is when DHCP is used to assign an IP address to a mobile
   phone or a tablet and where the 'chaddr' field is set to zero in DHCP
   request packets.  In such cases, the client usually sets the 'client

Swamy, et al.                Standards Track                    [Page 2]
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