draft-ietf-dnsext-unknown-rrs-05.txt

bind-3.2.

   As a result, when a new RR type contains one or more embedded domain
   names, it is possible to have multiple RRs owned by the same name
   that differ only in the character case of the embedded domain
   name(s).  This is similar to the existing possibility of multiple TXT
   records differing only in character case, and not expected to cause
   any problems in practice.

7. DNSSEC Canonical Form and Ordering

   DNSSEC defines a canonical form and ordering for RRs [RFC2535,
   section 8.1].  In that canonical form, domain names embedded in the
   RDATA are converted to lower case.

   The downcasing is necessary to ensure the correctness of DNSSEC
   signatures when case distinctions in domain names are lost due to
   compression, but since it requires knowledge of the presence and
   position of embedded domain names, it cannot be applied to unknown
   types.

   To ensure continued consistency of the canonical form of RR types
   where compression is allowed, and for continued interoperability with
   existing implementations that already implement the RFC2535 canonical
   form and apply it to their known RR types, the canonical form remains
   unchanged for all RR types whose whose initial publication as an RFC
   was prior to the initial publication of this specification as an RFC
   (RFC TBD).

   As a courtesy to implementors, it is hereby noted that the complete
   set of such previously published RR types that contain embedded
   domain names, and whose DNSSEC canonical form therefore involves
   downcasing according to the DNS rules for character comparisons,
   consists of the RR types NS, MD, MF, CNAME, SOA, MB, MG, MR, PTR,
   HINFO, MINFO, MX, HINFO, RP, AFSDB, RT, SIG, PX, NXT, NAPTR, KX, SRV,
   DNAME, and A6.

   This document specifies that for all other RR types (whether treated
   as unknown types or treated as known types according to an RR type
   definition RFC more recent than than RFC TBD), the canonical form is
   such that no downcasing of embedded domain names takes place, and
   otherwise identical to the canonical form specified in RFC2535
   section 8.1.

   Note that the owner name is always set to lower case according to the
   DNS rules for character comparisons, regardless of the RR type.

   The DNSSEC canonical RR ordering is as specified in RFC2535 section
   8.3, where the octet sequence is the canonical form as revised by
   this specification.



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8. Additional Section Processing

   Unknown RR types cause no additional section processing.  Future RR
   type specifications MAY specify type-specific additional section
   processing rules, but any such processing MUST be optional as it can
   only be performed by servers for which the RR type in case is known.

9. IANA Considerations

   The IANA is hereby requested to verify that specifications for new RR
   types requesting an RR type number comply with this specification.
   In particular, the IANA MUST NOT assign numbers to new RR types whose
   specification allows embedded domain names to be compressed.

10. Security Considerations

   This specification is not believed to cause any new security
   problems, nor to solve any existing ones.

Normative References

   [RFC1034] - Domain Names - Concepts and Facilities, P. Mockapetris,
   November 1987.

   [RFC1035] - Domain Names - Implementation and Specifications, P.
   Mockapetris, November 1987.

   [RFC1123] - Requirements for Internet Hosts -- Application and
   Support, R. Braden, Editor, October 1989.

   [RFC2119] - Key words for use in RFCs to Indicate Requirement Levels,
   S. Bradner, BCP 14, March 1997.

   [RFC2535] - Domain Name System Security Extensions. D. Eastlake,
   March 1999.

   [RFC2613] - Using the Internet DNS to Distribute MIXER Conformant
   Global Address Mapping (MCGAM), C. Allocchio, January 1998.

   [RFC2929] - Domain Name System (DNS) IANA Considerations, D.
   Eastlake, E. Brunner-Williams, B. Manning, September 2000.

Non-normative References

   [RFC1876] - A Means for Expressing Location Information in the Domain
   Name System, C. Davis, P. Vixie, T. Goodwin, I. Dickinson, January
   1996.




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   [RFC2052] - A DNS RR for specifying the location of services (DNS
   SRV), A. Gulbrandsen, P. Vixie, October 1996.  Obsoleted by RFC2782.

   [RFC2136] - Dynamic Updates in the Domain Name System (DNS UPDATE),
   P. Vixie, Ed., S. Thomson, Y. Rekhter, J. Bound, April 1997.

   [RFC2782] - A DNS RR for specifying the location of services (DNS
   SRV),  A. Gulbrandsen, P. Vixie, L. Esibov, February 2000.

Author's Address

   Andreas Gustafsson
   Nominum Inc.
   2385 Bay Rd
   Redwood City, CA 94063
   USA

   Phone: [phone]

   Email: [e-mail]


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   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE."

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