--- 1/draft-ietf-dnsext-rfc6195bis-04.txt 2012-10-14 02:14:01.693424872 +0200 +++ 2/draft-ietf-dnsext-rfc6195bis-05.txt 2012-10-14 02:14:01.729425651 +0200 @@ -1,19 +1,19 @@ INTERNET-DRAFT Donald Eastlake Obsoletes: 6195 Huawei Updates: 1183, 2845, 2930, 3597 Intended status: Best Current Practice -Expires: January 14, 2013 July 15, 2012 +Expires: April 12, 2013 October 13, 2012 Domain Name System (DNS) IANA Considerations - + Abstract This document specifies Internet Assigned Number Authority (IANA) parameter assignment considerations for the allocation of Domain Name System (DNS) resource record types, CLASSes, operation codes, error codes, DNS protocol message header bits, and AFSDB resource record subtypes. It obsoletes RFC 6195 and updates RFCs 1183, 2845, 2930, and 3597. @@ -40,37 +40,37 @@ http://www.ietf.org/1id-abstracts.html. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. INTERNET-DRAFT DNS IANA Considerations Table of Contents 1. Introduction............................................3 1.1 Terminology............................................3 - 1.2 Acknowledgement........................................3 + 1.2 Acknowledgements.......................................3 2. DNS Query/Response Headers..............................4 2.1 One Spare Bit?.........................................5 2.2 OpCode Assignment......................................5 2.3 RCODE Assignment.......................................5 3. DNS Resource Records....................................8 3.1 RRTYPE IANA Considerations.............................9 3.1.1 DNS RRTYPE Allocation Policy........................10 3.1.2 DNS RRTYPE Expert Guidelines........................11 - 3.1.3 Special Note on the OPT RR..........................11 + 3.1.3 Special Note on the OPT RR..........................12 3.1.4 The AFSDB RR Subtype Field..........................12 3.2 RR CLASS IANA Considerations..........................12 3.3. Label Considerations.................................14 3.3.1 Label Types.........................................14 - 3.3.2 Label Contents and Use..............................14 + 3.3.2 Label Contents and Use..............................15 4. Security Considerations................................16 5. IANA Considerations....................................16 Appendix A: RRTYPE Allocation Template....................17 Appendix B: Changes From RFC 6195.........................18 Normative References......................................19 Informative References....................................20 @@ -95,36 +95,33 @@ significant changes are those to the RRTYPE IANA allocation process, aimed at streamlining it and clarifying the expected behavior of the parties involved, and the closing of the AFSDB sub-type registry. IANA currently maintains a web page of DNS parameters available from http://www.iana.org. 1.1 Terminology "Standards Action", "IETF Review", "Specification Required", and - "Private Use" are as defined in [RFC5226]. 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 [RFC2119]. + "Private Use" are as defined in [RFC5226]. -1.2 Acknowledgement +1.2 Acknowledgements - Alfred Hoenes contributions are gratefully acknowledged as are those + Alfred Hoenes' contributions are gratefully acknowledged as are those by Mark Andrews, Dick Franks, and Michael Sheldon. INTERNET-DRAFT DNS IANA Considerations 2. DNS Query/Response Headers The header for DNS queries and responses contains field/bits in the - following diagram taken from [RFC2136] and [RFC6195]: + following diagram taken from [RFC2136]: 1 1 1 1 1 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| OpCode |AA|TC|RD|RA| Z|AD|CD| RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT/ZOCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ @@ -180,21 +177,21 @@ 0 Query [RFC1035] 1 IQuery (Inverse Query, Obsolete) [RFC3425] 2 Status [RFC1035] 3 available for assignment 4 Notify [RFC1996] 5 Update [RFC2136] 6-15 available for assignment Although the Status OpCode is reserved in [RFC1035], its behavior has not been specified. New OpCode assignments require a Standards Action - as modified by [RFC4020]. + with early allocation permitted as specified in [RFC4020]. 2.3 RCODE Assignment It would appear from the DNS header above that only four bits of RCODE, or response/error code, are available. However, RCODEs can appear not only at the top level of a DNS response but also inside TSIG RRs [RFC2845], TKEY RRs [RFC2930], and extended by OPT RRs [RFC2671bis]. The OPT RR provides an 8-bit extension to the 4 header bits resulting in a 12-bit RCODE field, and the TSIG and TKEY RRs have a 16-bit field designated in their RFCs as the "Error" field. @@ -204,38 +201,39 @@ code 16, which has a different meaning in the OPT RR than in the TSIG RR, and error code 9 whose variations are described after the table below. The duplicate assignment of 16 was accidental. To the extent that any prior RFCs imply any sort of different error number space for the OPT, TSIG, or TKEY RRs, they are superseded by this unified DNS error number space. (This paragraph is the reason this document updates [RFC2845] and [RFC2930].) With the existing exceptions of INTERNET-DRAFT DNS IANA Considerations - error numbers 9 and 16, the same error number MUST NOT be assigned + error numbers 9 and 16, the same error number must not be assigned for different errors even if they would only occur in different RR types. See table below. RCODE Name Description Reference Decimal Hexadecimal 0 NoError No Error [RFC1035] 1 FormErr Format Error [RFC1035] 2 ServFail Server Failure [RFC1035] 3 NXDomain Non-Existent Domain [RFC1035] 4 NotImp Not Implemented [RFC1035] 5 Refused Query Refused [RFC1035] 6 YXDomain Name Exists when it should not [RFC2136] 7 YXRRSet RR Set Exists when it should not [RFC2136] 8 NXRRSet RR Set that should exist does not [RFC2136] - 9 NotAuth See note below after table + 9 NotAuth Server Not Authoritative for zone [RFC2136] + 9 NotAuth Not Authorized [RFC2845] 10 NotZone Name not contained in zone [RFC2136] 11 - 15 0xB - 0xF Available for assignment 16 BADVERS Bad OPT Version [RFC2671bis] 16 BADSIG TSIG Signature Failure [RFC2845] 17 BADKEY Key not recognized [RFC2845] 18 BADTIME Signature out of time window [RFC2845] 19 BADMODE Bad TKEY Mode [RFC2930] @@ -249,28 +247,28 @@ 3,841 - 4,095 0x0F01 - 0x0FFF Private Use 4,096 - 65,534 0x1000 - 0xFFFE Available for assignment 65,535 0xFFFF Reserved, can only be allocated by a Standards Action. - Note on error number 9 (NOTAUTH): This error number means either "Not + Note on error number 9 (NotAuth): This error number means either "Not Authoritative" [RFC2136] or "Not Authorized" [RFC2845]. If 9 appears as the RCODE in the header of a DNS response without a TSIG RR or with a TSIG RR having a zero error field, then it means - "Not Authoritative". If 9 appears as the RCODE in the header of a INTERNET-DRAFT DNS IANA Considerations + "Not Authoritative". If 9 appears as the RCODE in the header of a DNS response that includes a TSIG RR with a non-zero error field, then it means "Not Authorized". Since it is important that RCODEs be understood for interoperability, assignment of a new RCODE in the ranges listed above as "Available for assignment" requires an IETF Review. INTERNET-DRAFT DNS IANA Considerations 3. DNS Resource Records @@ -399,91 +397,96 @@ Parameter values specified in Section 3.1 above as assigned based on DNS RRTYPE Allocation Policy, are allocated by Expert Review if they meet the two requirements listed below. There will be a pool of a small number of Experts appointed by the IESG. Each application will be judged by an Expert selected by IANA. In any case where the selected Expert is unavailable or states they have a conflict of interest, IANA may select another Expert from the pool. Some guidelines for the Experts are given in Section 3.1.2. RRTYPEs that do not meet the requirements below may nonetheless be - allocated by a Standards Action as modified by [RFC4020]. + allocated by a Standards Action with early allocation permitted as + specified in [RFC4020]. 1. A complete template as specified in Appendix A has been posted to the dns-rrtype-applications@ietf.org mailing list and received by the Expert. Note that the posting of partially completed, draft, or formally submitted templates to dnsext@ietf.org by the applicant or Expert for comment and discussion is highly encouraged. Formal submission of an RRTYPE template without consideration of some community review can be expected to increase the probability of initial rejection leading to a need to re-submit after modification. 2. The RR for which an RRTYPE code is being requested is either (a) a data TYPE that can be handled as an Unknown RR as described in [RFC3597] or (b) a Meta-TYPE whose processing is optional, i.e., it is safe to simply discard RRs with that Meta-TYPE in queries or responses. - Note that such RRs may include additional section processing, INTERNET-DRAFT DNS IANA Considerations + Note that such RRs may include additional section processing, provided such processing is optional. After the applicant submits their formal application to IANA by sending the completed template specified in Appendix A to the dns- rrtype-applications@ietf.org mailing list, IANA appoints an Expert and sends the completed template to the Expert copying the applicant. No more than two weeks after receiving the application the Expert shall explicitly approve or reject the application, informing IANA, - the applicant, and the dnsext@ietf.org mailing list. The Expert - should consult with other technical experts and the dnsext@ietf.org - mailing list as necessary. If the Expert does not approve the - application within this period, it is considered rejected. IANA - should report non-responsive Experts to the IESG. + the applicant, and the dnsext@ietf.org mailing list. A rejection + should include the reason for rejection and may include suggestions + for improvement. The Expert should consult with other technical + experts and the dnsext@ietf.org mailing list as necessary. If the + Expert does not approve the application within this period, it is + considered rejected. IANA should report non-responsive Experts to the + IESG. IANA shall maintain a public archive of approved templates. In addition, if the required description of the RRTYPE applied for is referenced by URL, a copy of the document so referenced should be included in the archive. 3.1.2 DNS RRTYPE Expert Guidelines - The Expert should normally reject any RRTYPE allocation request that - meets one or more of the following criteria: + The Designated Expert should normally be lenient, preferring to + approve most requests. However, the Expert should usually reject any + RRTYPE allocation request that meets one or more of the following + criteria: 1. Was documented in a manner that was not sufficiently clear or complete to evaluate or implement. (Additional documentation can be provided during the Expert review period.) 2. The proposed RRTYPE or RRTYPEs affect DNS processing and do not meet the criteria in point 2 of Section 3.1.1 above. 3. Application use as documented makes incorrect assumptions about DNS protocol behavior, such as wild cards, CNAME, DNAME, etc. 4. An excessive number of RRTYPE values is being requested when the purpose could be met with a smaller number or with Private Use values. +INTERNET-DRAFT DNS IANA Considerations + 3.1.3 Special Note on the OPT RR The OPT (OPTion) RR (RRTYPE 41) and its IANA considerations are specified in [RFC2671bis]. Its primary purpose is to extend the effective field size of various DNS fields including RCODE, label type, OpCode, flag bits, and RDATA size. In particular, for resolvers and servers that recognize it, it extends the RCODE field from 4 to 12 bits. -INTERNET-DRAFT DNS IANA Considerations - 3.1.4 The AFSDB RR Subtype Field The AFSDB RR [RFC1183] is a CLASS-insensitive RR that has the same RDATA field structure as the MX RR [RFC1035], but the 16-bit unsigned integer field at the beginning of the RDATA is interpreted as a subtype as shown below. Use of the AFSDB RR to locate AFS cell database servers was deprecated by [RFC5864]. This subtype registry is hereby closed and allocation of new subtypes is no longer permitted. @@ -507,34 +510,33 @@ 65,535 0xFFFF Reserved, registry closed 3.2 RR CLASS IANA Considerations There are currently two subcategories of DNS CLASSes: normal, data- containing classes and QCLASSes that are only meaningful in queries or updates. +INTERNET-DRAFT DNS IANA Considerations + DNS CLASSes have been little used but constitute another dimension of the DNS distributed database. In particular, there is no necessary relationship between the name space or root servers for one data CLASS and those for another data CLASS. The same DNS NAME can have completely different meanings in different CLASSes. The label types are the same, and the null label is usable only as root in every CLASS. As global networking and DNS have evolved, the IN, or Internet, CLASS has dominated DNS use. As yet, there has not been a requirement for "meta-CLASSes". That would be a CLASS to designate transient data associated with a - -INTERNET-DRAFT DNS IANA Considerations - particular DNS message, which might be usable in queries. However, it is possible that there might be a future requirement for one or more "meta-CLASSes". Assigned CLASSes have mnemonics that must be completely disjoint from the mnemonics used for RRTYPEs and that must match the regular expression below. In addition, the generic CLASS and RRTYPE names specified in Section 5 of [RFC3597] cannot be assigned as new CLASS mnemonics. @@ -561,32 +563,32 @@ 3 0x0003 Chaos (CH) [Moon1981] 4 0x0004 Hesiod (HS) [Dyer1987] 5 - 127 0x0005 - 0x007F Available for assignment by IETF Review for data CLASSes only +INTERNET-DRAFT DNS IANA Considerations + 128 - 253 0x0080 - 0x00FD Available for assignment by IETF Review for QCLASSes and meta-CLASSes only 254 0x00FE QCLASS NONE [RFC2136] 255 0x00FF QCLASS * (ANY) [RFC1035] -INTERNET-DRAFT DNS IANA Considerations - 256 - 32,767 0x0100 - 0x7FFF Available for assignment by IETF Review 32,768 - 57,343 0x8000 - 0xDFFF Available for assignment to data CLASSes only; Specification Required 57,344 - 65,279 0xE000 - 0xFEFF Available for assignment to QCLASSes and meta- CLASSes only; Specification Required @@ -610,30 +612,29 @@ shorten the wire encoding of NAMEs. The two existing data label types are sometimes referred to as Text and Binary. Text labels can, in fact, include any octet value including zero-value octets, but many current uses involve only printing ASCII characters [US-ASCII]. For retrieval, Text labels are defined to treat ASCII upper and lower case letter codes as matching [RFC4343]. Binary labels are bit sequences [RFC2673]. The Binary label type is Historic [RFC2671bis]. +INTERNET-DRAFT DNS IANA Considerations + 3.3.2 Label Contents and Use The last label in each NAME is "ROOT", which is the zero-length label. By definition, the null or ROOT label cannot be used for any other NAME purpose. NAMEs are local to a CLASS. The Hesiod [Dyer1987] and Chaos - -INTERNET-DRAFT DNS IANA Considerations - [Moon1981] CLASSes are for essentially local use. The IN, or Internet, CLASS is thus the only DNS CLASS in global use on the Internet at this time. A somewhat out-of-date description of name allocation in the IN Class is given in [RFC1591]. Some information on reserved top-level domain names is in BCP 32 [RFC2606]. INTERNET-DRAFT DNS IANA Considerations @@ -685,22 +686,23 @@ experts that may have limited knowledge of your application space. E. Description of the proposed RR type. This description can be provided in-line in the template, as an attachment, or with a publicly available URL. F. What existing RRTYPE or RRTYPEs come closest to filling that need and why are they unsatisfactory? G. What mnemonic is requested for the new RRTYPE (optional)? - Note: this can be left blank and the mnemonic decided after the - template is accepted. + Note: If a mnemonic is not supplied, not allowed, or duplicates an + existing RRTYPE or CLASS mnemonic, the Expert will assign a + mnemonic. H. Does the requested RRTYPE make use of any existing IANA registry or require the creation of a new IANA sub-registry in DNS Parameters? If so, please indicate which registry is to be used or created. If a new sub-registry is needed, specify the allocation policy for it and its initial contents. Also include what the modification procedures will be. I. Does the proposal require/expect any changes in DNS servers/resolvers that prevent the new type from being processed @@ -733,44 +735,41 @@ Addition of text and an exclusory regular expression to Sections 3.1 and 3.2 to prohibit the use of a slight generalization of the generic CLASS and RRTYPE names specified in [RFC3597] as the mnemonics for new CLASSes and RRTYPEes. Parenthetically list "ANY" and well as "ALL" as a meaning for the "*" RRTYPE. Clarify that there is one DNS error number space for headers, OPT - extended headers, TSIG RRs, and TKEY RRs. Note that this can be + extended headers, TSIG RRs, and TKEY RRs. Note that this is considered to update [RFC2845] and [RFC2930]. Note the overloading of error number 9 as well as 16. Update references for revised versions. A number of editorial changes and typo fixes. INTERNET-DRAFT DNS IANA Considerations Normative References [RFC1034] - Mockapetris, P., "Domain names - concepts and facilities", STD 13, RFC 1034, November 1987. [RFC1035] - Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, November 1987. [RFC1996] - Vixie, P., "A Mechanism for Prompt Notification of Zone Changes (DNS NOTIFY)", RFC 1996, August 1996. - [RFC2119] - Bradner, S., "Key words for use in RFCs to Indicate - Requirement Levels", BCP 14, RFC 2119, March 1997 - [RFC2136] - Vixie, P., Ed., Thomson, S., Rekhter, Y., and J. Bound, "Dynamic Updates in the Domain Name System (DNS UPDATE)", RFC 2136, April 1997. [RFC2181] - Elz, R. and R. Bush, "Clarifications to the DNS Specification", RFC 2181, July 1997. [RFC2845] - Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B. Wellington, "Secret Key Transaction Authentication for DNS (TSIG)", RFC 2845, May 2000. @@ -793,26 +792,26 @@ 4033, March 2005. [RFC4034] - Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "Resource Records for the DNS Security Extensions", RFC 4034, March 2005. [RFC4035] - Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "Protocol Modifications for the DNS Security Extensions", RFC 4035, March 2005. -INTERNET-DRAFT DNS IANA Considerations - [RFC4635] - Eastlake 3rd, D., "HMAC SHA (Hashed Message Authentication Code, Secure Hash Algorithm) TSIG Algorithm Identifiers", RFC 4635, August 2006. +INTERNET-DRAFT DNS IANA Considerations + [RFC5226] - Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. [RFC2671bis] - Damas, J., Graff, M., and Vixie, P., "Extension Mechanisms for DNS (EDNS0)", draft-ietf-dnsext- rfc2671bis-edns0, work in progress. [RFCdnssecbisup] - Weiler, A. and D. Blacka, "Clarifications and Implementation Notes for DNSSECbis", draft-ietf-dnsext- @@ -843,25 +842,25 @@ [RFC2606] - Eastlake 3rd, D. and A. Panitz, "Reserved Top Level DNS Names", BCP 32, RFC 2606, June 1999. [RFC2673] - Crawford, M., "Binary Labels in the Domain Name System", RFC 2673, August 1999. [RFC2931] - Eastlake 3rd, D., "DNS Request and Transaction Signatures ( SIG(0)s )", RFC 2931, September 2000. -INTERNET-DRAFT DNS IANA Considerations - [RFC4343] - Eastlake 3rd, D., "Domain Name System (DNS) Case Insensitivity Clarification", RFC 4343, January 2006. +INTERNET-DRAFT DNS IANA Considerations + [RFC5864] - Allbery, R., "DNS SRV Resource Records for AFS", RFC 5864, April 2010. [RFC6195] - Eastlake 3rd, D., "Domain Name System (DNS) IANA Considerations", RFC 6195, March 2011. INTERNET-DRAFT DNS IANA Considerations Author's Address