Network Working Group M. Andrews Request for Comments: 4431 Internet Systems Consortium Category: Informational S. Weiler SPARTA, Inc. February 2006 The DNSSEC Lookaside Validation (DLV) DNS Resource Record Status of This Memo This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2006).
AbstractThis 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. 1]   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. This document defines a new resource record for publishing such trust anchors outside of the DNS's normal delegation chain. Use of these records by DNSSEC validators is outside the scope of this document, but it is expected that these records will help resolvers validate DNSSEC-signed data from zones whose ancestors either aren't signed or refuse to publish delegation signer (DS) records for their children. RFC 4034, 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.)
The DLV record is a normal DNS record type without any special processing requirements. In particular, the DLV record does not inherit any of the special processing or handling requirements of the DS record type (described in Section 22.214.171.124 of RFC 4035). Unlike the DS record, the DLV record may not appear on the parent's side of a zone cut. A DLV record may, however, appear at the apex of a zone. RFC 4034, Section 8, describes security considerations specific to the DS RR. Those considerations are equally applicable to DLV RRs. Of particular note, the key tag field is used to help select DNSKEY RRs efficiently, but it does not uniquely identify a single DNSKEY RR. 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 circumstances. For further discussion of the security implications of DNSSEC, see RFC 4033, RFC 4034, and RFC 4035. 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.
 Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "DNS Security Introduction and Requirements", RFC 4033, March 2005.  Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "Resource Records for the DNS Security Extensions", RFC 4034, March 2005.  Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "Protocol Modifications for the DNS Security Extensions", RFC 4035, March 2005.  Eastlake, D., Brunner-Williams, E., and B. Manning, "Domain Name System (DNS) IANA Considerations", BCP 42, RFC 2929, September 2000.
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