DHC Working Group Narasimha Swamy INTERNET DRAFT Nokia Networks Updates: RFC 2131 January 2004 Expires July 2004 Client Identifier option in server replies <draft-ietf-dhc-client-id-00.txt> Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract This document clarifies the use of 'client identifier' option by the clients and servers as mentioned in [RFC2131]. The clarification addresses the issue arising out of the point specified by [RFC2131] that the server 'MUST NOT' return client identifier' option to the client. Swamy Expires July 2004 [Page 1]
Internet Draft Client Identifier January 2004 1. Introduction In some cases, client may not be having valid hardware address value to be filled in 'chaddr' field of the packet (one such example is when DHCP is used to assign IP addresses to Mobile phones). In this case, client sets 'client identifier' option, and both client and server use this field to uniquely identify the client with in a subnet. But [RFC2131] specifies that server "MUST NOT" return 'client identifier' in DHCPOFFER and DHCPACK messages. In this case, when a client receives response from server, it can't guarantee that response is intended for it. Note that even though 'xid' field is present to map responses with requests, this field alone can't guar- antee that a particular response is for a particular client, as 'xid' values generated by multiple clients within a subnet need not be unique. This draft proposes modification to server behavior to addr- ess this problem. 2. Terminology 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 [RFC 2119]. This document uses the following terms: o "DHCP client" A DHCP client is an Internet host using DHCP to obtain confi- guration parameters such as a network address. o "DHCP server" A DHCP server is an Internet host that returns configuration parameters to DHCP clients. 3. Proposed modification to [RFC2131] If the 'client identifier' option is set in the message received from client, the server MUST return 'client identifier' value in its response message. Following table is extracted from section 4.3.1 of [RFC2131] and relevant fields are modified accordingly. Option DHCPOFFER DHCPACK DHCPNAK ------ --------- ------- ------- Client identifier MAY MAY MAY Table 1: Options used by DHCP servers Swamy Expires July 2004 [Page 2]
Internet Draft Client Identifier January 2004 4. Security Considerations No known security considerations. 5. Acknowledgments I would like to thank Umesh Kulkarni, Harish Raghuveer and Hari Mallath for their support and feedback. 6. References [RFC 951] Croft, B., Gilmore, J., "Bootstrap Protocol (BOOTP)", RFC 951, September 1985. [RFC 1542] Wimer, W., "Clarifications and Extensions for the Bootstrap Protocol", RFC 1542, October 1993. [RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997. [RFC 2131] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, March 1997. [RFC 2132] Alexander, S., Droms, R., "DHCP Options and BOOTP Vendor Extensions", RFC 2132, March 1997. 7. Author's information Narasimha Swamy Nokia India Pvt Ltd #88, Gandhi Bazaar Main Road Basavanagudi Bangalore - 560 004 Phone: +91 80 51189628 Email: narasimha.nelakuditi@nokia.com 8. Intellectual Property Statement The IETF takes no position regarding the validity or scope of any intel- lectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. Information on the IETF's procedures with Swamy Expires July 2004 [Page 3]
Internet Draft Client Identifier January 2004 respect to rights in standards-track and standards-related documentation can be found in BCP-11. Copies of claims of rights made available for publication and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementors or users of this specification can be obtained from the IETF Secretariat. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights which may cover technology that may be required to practice this stan- dard. Please address the information to the IETF Executive Director. 9. Full Copyright Statement Copyright (C) The Internet Society (2003). All Rights Reserved. This document and translations of it may be copied and furnished to oth- ers, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and dis- tributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Stan- dards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FIT- NESS FOR A PARTICULAR PURPOSE. Swamy Expires July 2004 [Page 4]
