Client Identifier Option in DHCP Server Replies
RFC 6842
Document | Type |
RFC - Proposed Standard
(January 2013; No errata)
Updates RFC 2131
|
|
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Authors | Narasimha Swamy , Gaurav Halwasia , Unit Sez | ||
Last updated | 2015-10-14 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Reviews | |||
Stream | WG state | WG Document | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 6842 (Proposed Standard) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Ralph Droms | ||
IESG note | Ted Lemon (Ted.Lemon@nominum.com) is the Document Shepherd. | ||
Send notices to | (None) |
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] RFC 6842 Client Identifier Option January 2013 identifier' option field (to a value as permitted in [RFC2131]), and both the client and server use this field to uniquely identify the client with in a subnet. Note that due to aforementioned recommendations in [RFC2131], valid downstream DHCP packets (DHCPOFFER, DHCPACK, and DHCPNAK) from theShow full document text