INTERNET-DRAFT Andreas Gustafsson draft-ietf-dnsind-dhcp-rr-00.txt Internet Engines, Inc. October 1999 A DNS RR for encoding DHCP information 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. Abstract This document describes a DNS RR for use by DHCP servers that need to store state information in the DNS. Introduction A set of procedures to allow DHCP servers [RFC2131] to automatically update the DNS [RFC1034, RFC1035] is proposed in [DHCPDNS]. A situation can arise where multiple DHCP clients request the same DNS name from their (possibly distinct) DHCP servers. To resolve such conflicts, [DHCPDNS] proposes storing client identifiers in the DNS to unambiguously associate domain names with the DHCP clients "owning" them. Early versions of [DHCPDNS] proposed using TXT records for encoding this information; the current version specifies the use of KEY records. In the interest of clarity, it would be preferable for this DHCP Expires April 2000 [Page 1] draft-ietf-dnsind-dhcp-rr-00.txt October 1999 information to use a distinct RR type rather than the existing KEY type. A separate RR type can also improve efficiency by avoiding the unnecessary transmission of unrelated KEY records. This memo defines a distinct RR type for use by DHCP servers, the "DHCP" RR. The DHCP RR The DHCP RR is defined with mnemonic DHCP and type code . DHCP RDATA format The RDATA section of a DHCP RR in transmission contains RDLENGTH bytes of binary data. The format of this data and its interpretation by DHCP servers and clients, including the interpretation of multiple DHCP RRs at the same domain name, are TBD. [This part of the specification should be driven by the needs of, and written in cooperation with, the DHCP Working Group and the authors of [DHCPDNS]]. DNS software should consider the RDATA section to be opaque. In DNS master files, the RDATA is represented as a hexadecimal string with an optional "0x" or "0X" prefix. Periods (".") may be inserted anywhere after the "0x" for readability. This format is identical to that of the NSAP RR [RFC1706]. The number of hexadecimal digits MUST be even. Example A DHCP server allocating the IPv4 address 10.0.0.1 to a client "client.org.nil" might associate eight bytes of housekeeping information with the client as follows: client.org.nil. A 10.0.0.1 client.org.nil. DHCP 01.23.45.67.89.ab.cd.ef Security Considerations The DHCP record as such does not introduce any new security problems into the DNS. However, care should be taken not to store sensitive information in DHCP records, since they are published along with other DNS data. Note that even the hardware addresses of DHCP clients may be considered sensitive information. IANA Considerations The IANA is requested to allocate an RR type number for the DHCP Expires April 2000 [Page 2] draft-ietf-dnsind-dhcp-rr-00.txt October 1999 record type from the regular RR type number range. References [RFC1035] - Domain Names - Implementation and Specifications, P. Mockapetris, November 1987. [RFC1034] - Domain Names - Concepts and Facilities, P. Mockapetris, November 1987. [RFC1706] - DNS NSAP Resource Records, B. Manning, R. Colella, October 1994. [RFC2131] - Dynamic Host Configuration Protocol, R. Droms, March 1997. [DHCPDNS] - draft-ietf-dhc-dhcp-dns-*.txt Author's Address Andreas Gustafsson Internet Engines, Inc. 950 Charter Street Redwood City, CA 94063 USA Phone: +1 650 779 6004 Email: gson@iengines.net Full Copyright Statement Copyright (C) The Internet Society (1999). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implmentation may be prepared, copied, published and distributed, 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 Standards process must be followed, or as required to translate it into languages other than English. Expires April 2000 [Page 3] draft-ietf-dnsind-dhcp-rr-00.txt October 1999 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 FITNESS FOR A PARTICULAR PURPOSE." Expires April 2000 [Page 4]