Network Working Group M. Andrews Internet-Draft Internet Systems Consortium Expires: December 25, 2005 S. Weiler SPARTA, Inc. June 23, 2005 The DNSSEC Lookaside Validation (DLV) DNS Resource Record draft-andrews-dlv-dns-rr-00 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. 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. This Internet-Draft will expire on December 25, 2005. Copyright Notice Copyright (C) The Internet Society (2005). Abstract This document defines a new DNS Resource Record, called the DNSSEC Lookaside Validation (DLV) RR, for publishing DNSSEC trust anchors outside of the DNS delegation chain. These records allow resolvers to validate DNSSEC-signed data from zones whose ancestors either aren't signed or refuse to publish DS records for their children. Andrews & Weiler Expires December 25, 2005 [Page 1] Internet-Draft DLV Resource Record June 2005 1. Introduction DNSSEC [1] [2] [3] authenticates DNS data by building public-key signature chains along the DNS delegation chain from a trust anchor, ideally a trust anchor for the DNS root. Due to a myriad of technical and political concerns, it appears unlikely that many delegation-heavy zones, including the root and most generic top level domains (gTLDs), will sign their zones in the near future, which leaves DNS resolvers with no means to validate data from the children of those zones without maintaining a large number of preconfigured keys. This document defines a new resource record for publishing trust anchors outside of the DNS's normal delegation chain. Use of these records by validators is outside the scope of this document. 2. DLV Resource Record The DLV resource record has exactly the same wire and presentation formats as the DS resource record, defined in RFC4034 Section 5. It uses the same IANA-assigned values in the algorithm and digest type fields as the DS record. (Those IANA registries are known as the "DNS Security Algorithm Numbers" and "DS RR Type Algorithm Numbers" registries.) Unlike the DS record, the DLV record may not appear on the parent's side of a zone cut. Consequently, DLV records do not require the special processing described in section 3.1.4.1 of RFC4035. DLV records may appear at the apex of a zone. 3. Security Considerations Publishing DLV records introduces no security problems -- they're just DNS data. Users of DLV records will almost certainly want to impose constraints on their use, but those constraints are best left to be described by the users of the records. At a minimum, it would be wise to not use the records without some sort of cryptographic authentication. RFC4034 Section 8 describes security considerations specific to the DS resource record. Those considerations are equally applicable to DLV records. Of particular note, the key tag field is used to help select DNSKEY resource records efficiently, but it does not uniquely identify a single DNSKEY resource record. It is possible for two distinct DNSKEY RRs to have the same owner name, the same algorithm type, and the same key tag. An implementation that uses only the key tag to select a DNSKEY RR might select the wrong public key in some Andrews & Weiler Expires December 25, 2005 [Page 2] Internet-Draft DLV Resource Record June 2005 circumstances. For discussion of the security implications of DNSSEC see RFC4033, RFC4034, and RFC4035. 4. IANA Considerations IANA has assigned DNS type code X to the DLV resource record from the Specification Required portion of the DNS Resource Record Type registry, as defined in [4]. The DLV resource record reuses the same algorithm and digest type registries already used for the DS resource record, currently known as the "DNS Security Algorithm Numbers" and "DS RR Type Algorithm Numbers" registries. 5. Normative References [1] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "DNS Security Introduction and Requirements", RFC 4033, March 2005. [2] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "Resource Records for the DNS Security Extensions", RFC 4034, March 2005. [3] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "Protocol Modifications for the DNS Security Extensions", RFC 4035, March 2005. [4] Eastlake, D., Brunner-Williams, E., and B. Manning, "Domain Name System (DNS) IANA Considerations", BCP 42, RFC 2929, September 2000. Authors' Addresses Mark Andrews Internet Systems Consortium 950 Charter St. Redwood City, CA 94063 US Email: Mark_Andrews@isc.org Andrews & Weiler Expires December 25, 2005 [Page 3] Internet-Draft DLV Resource Record June 2005 Samuel Weiler SPARTA, Inc. 7075 Samuel Morse Drive Columbia, Maryland 21046 US Email: weiler@tislabs.com Andrews & Weiler Expires December 25, 2005 [Page 4] Internet-Draft DLV Resource Record June 2005 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights 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; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. 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Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM 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. Copyright Statement Copyright (C) The Internet Society (2005). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Andrews & Weiler Expires December 25, 2005 [Page 5]