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Internet Engineering Task Force (IETF) D. Eastlake 3rd Request for Comments: 6895 Huawei BCP: 42 April 2013 Obsoletes: 6195 Updates: 1183, 2845, 2930, 3597 Category: Best Current Practice ISSN: 2070-1721

            Domain Name System (DNS) IANA Considerations

Abstract

 This document specifies Internet Assigned Numbers 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.

Status of This Memo

 This memo documents an Internet Best Current Practice.
 This document is a product of the Internet Engineering Task Force
 (IETF).  It represents the consensus of the IETF community.  It has
 received public review and has been approved for publication by the
 Internet Engineering Steering Group (IESG).  Further information on
 BCPs is available in Section 2 of RFC 5741.
 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 http://www.rfc-editor.org/info/rfc6895.

Copyright Notice

 Copyright (c) 2013 IETF Trust and the persons identified as the
 document authors.  All rights reserved.
 This document is subject to BCP 78 and the IETF Trust's Legal
 Provisions Relating to IETF Documents
 (http://trustee.ietf.org/license-info) in effect on the date of
 publication of this document.  Please review these documents
 carefully, as they describe your rights and restrictions with respect
 to this document.  Code Components extracted from this document must
 include Simplified BSD License text as described in Section 4.e of
 the Trust Legal Provisions and are provided without warranty as
 described in the Simplified BSD License.

Eastlake Best Current Practice [Page 1] RFC 6895 DNS IANA Considerations April 2013

Table of Contents

 1. Introduction ....................................................2
    1.1. Terminology ................................................3
 2. DNS Query/Response Headers ......................................3
    2.1. One Spare Bit? .............................................4
    2.2. OpCode Assignment ..........................................4
    2.3. RCODE Assignment ...........................................4
 3. DNS Resource Records ............................................6
    3.1. RRTYPE IANA Considerations .................................7
         3.1.1. DNS RRTYPE Allocation Policy ........................8
         3.1.2. DNS RRTYPE Expert Guidelines .......................10
         3.1.3. Special Note on the OPT RR .........................10
         3.1.4. The AFSDB RR Subtype Field .........................10
    3.2. RR CLASS IANA Considerations ..............................11
    3.3. Label Considerations ......................................13
         3.3.1. Label Types ........................................13
         3.3.2. Label Contents and Use .............................13
 4. Security Considerations ........................................14
 5. IANA Considerations ............................................14
 Appendix A. RRTYPE Allocation Template ............................15
 Appendix B. Changes from RFC 6195 .................................16
 Normative References ..............................................17
 Informative References ............................................18
 Acknowledgements ..................................................19

1. Introduction

 The Domain Name System (DNS) provides replicated distributed secure
 hierarchical databases that store "resource records" (RRs) under
 domain names.  DNS data is structured into CLASSes and zones that can
 be independently maintained.  Familiarity with [RFC1034], [RFC1035],
 [RFC2136], [RFC2181], and [RFC4033] is assumed.
 This document provides, either directly or by reference, the general
 IANA parameter assignment considerations that apply across DNS query
 and response headers and all RRs.  There may be additional IANA
 considerations that apply to only a particular RRTYPE or
 query/response OpCode.  See the specific RFC defining that RRTYPE or
 query/response OpCode for such considerations if they have been
 defined, except for AFSDB RR considerations [RFC1183], which are
 included herein.  This RFC obsoletes [RFC6195]; however, the only
 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 subtype registry.
 IANA currently maintains a web page of DNS parameters available from
 <http://www.iana.org>.

Eastlake Best Current Practice [Page 2] RFC 6895 DNS IANA Considerations April 2013

1.1. Terminology

 "Standards Action", "IETF Review", "Specification Required", and
 "Private Use" are as defined in [RFC5226].

2. DNS Query/Response Headers

 The header for DNS queries and responses contains field/bits in the
 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                |
           +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
           |                ANCOUNT/PRCOUNT                |
           +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
           |                NSCOUNT/UPCOUNT                |
           +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
           |                    ARCOUNT                    |
           +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
 The ID field identifies the query and is echoed in the response so
 they can be matched.
 The QR bit indicates whether the header is for a query or a response.
 The AA, TC, RD, RA, and CD bits are each theoretically meaningful
 only in queries or only in responses, depending on the bit.  The AD
 bit was only meaningful in responses but is expected to have a
 separate but related meaning in queries (see Section 5.7 of
 [RFC6840]).  Only the RD and CD bits are expected to be copied from
 the query to the response; however, some DNS implementations copy all
 the query header as the initial value of the response header.  Thus,
 any attempt to use a "query" bit with a different meaning in a
 response or to define a query meaning for a "response" bit may be
 dangerous, given the existing implementation.  Meanings for these
 bits may only be assigned by a Standards Action.
 The unsigned integer fields query count (QDCOUNT), answer count
 (ANCOUNT), authority count (NSCOUNT), and additional information
 count (ARCOUNT) express the number of records in each section for all
 OpCodes except Update [RFC2136].  These fields have the same

Eastlake Best Current Practice [Page 3] RFC 6895 DNS IANA Considerations April 2013

 structure and data type for Update but are instead the counts for the
 zone (ZOCOUNT), prerequisite (PRCOUNT), update (UPCOUNT), and
 additional information (ARCOUNT) sections.

2.1. One Spare Bit?

 There have been ancient DNS implementations for which the Z bit being
 on in a query meant that only a response from the primary server for
 a zone is acceptable.  It is believed that current DNS
 implementations ignore this bit.
 Assigning a meaning to the Z bit requires a Standards Action.

2.2. OpCode Assignment

 Currently, DNS OpCodes are assigned as follows:
      OpCode Name                                Reference
       0     Query                               [RFC1035]
       1     IQuery (Inverse Query, OBSOLETE)    [RFC3425]
       2     Status                              [RFC1035]
       3     Unassigned
       4     Notify                              [RFC1996]
       5     Update                              [RFC2136]
      6-15   Unassigned
 Although the Status OpCode is reserved in [RFC1035], its behavior has
 not been specified.  New OpCode assignments require a Standards
 Action 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
 [RFC6891].  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.
 Error codes appearing in the DNS header and in these other RR types
 all refer to the same error code space with the exception of error
 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

Eastlake Best Current Practice [Page 4] RFC 6895 DNS IANA Considerations April 2013

 DNS error number space.  (This paragraph is the reason this document
 updates [RFC2845] and [RFC2930].)  With the existing exceptions of
 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   Server Not Authoritative for zone  [RFC2136]
         9    NotAuth   Not Authorized                     [RFC2845]
        10    NotZone   Name not contained in zone         [RFC2136]
        11 - 15
       0xB - 0xF        Unassigned
        16    BADVERS   Bad OPT Version                    [RFC6891]
        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]
        20    BADNAME   Duplicate key name                 [RFC2930]
        21    BADALG    Algorithm not supported            [RFC2930]
        22    BADTRUNC  Bad Truncation                     [RFC4635]
        23 - 3,840
    0x0017 - 0x0F00     Unassigned
     3,841 - 4,095
    0x0F01 - 0x0FFF     Reserved for Private Use
     4,096 - 65,534
    0x1000 - 0xFFFE     Unassigned
    65,535
    0xFFFF              Reserved; can only be allocated by Standards
                        Action.

Eastlake Best Current Practice [Page 5] RFC 6895 DNS IANA Considerations April 2013

    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
    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 "Unassigned"
 requires an IETF Review.

3. DNS Resource Records

 All RRs have the same top-level format, shown in the figure below
 taken from [RFC1035].
                                        1  1  1  1  1  1
          0  1  2  3  4  5  6  7  8  9  0  1  2  3  4  5
        +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
        |                                               |
        /                                               /
        /                     NAME                      /
        /                                               /
        +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
        |                     TYPE                      |
        +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
        |                     CLASS                     |
        +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
        |                     TTL                       |
        |                                               |
        +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
        |                   RDLENGTH                    |
        +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
        /                    RDATA                      /
        /                                               /
        +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
 NAME is an owner name, i.e., the name of the node to which this
 resource record pertains.  NAMEs are specific to a CLASS as described
 in Section 3.2.  NAMEs consist of an ordered sequence of one or more
 labels, each of which has a label type [RFC1035] [RFC6891].
 TYPE is a 2-octet unsigned integer containing one of the RRTYPE
 codes.  See Section 3.1.
 CLASS is a 2-octet unsigned integer containing one of the RR CLASS
 codes.  See Section 3.2.

Eastlake Best Current Practice [Page 6] RFC 6895 DNS IANA Considerations April 2013

 TTL is a 4-octet (32-bit) unsigned integer that specifies, for data
 TYPEs, the number of seconds that the resource record may be cached
 before the source of the information should again be consulted.  Zero
 is interpreted to mean that the RR can only be used for the
 transaction in progress.
 RDLENGTH is an unsigned 16-bit integer that specifies the length in
 octets of the RDATA field.
 RDATA is a variable-length string of octets that constitutes the
 resource.  The format of this information varies according to the
 TYPE and, in some cases, the CLASS of the resource record.

3.1. RRTYPE IANA Considerations

 There are three subcategories of RRTYPE numbers: data TYPEs, QTYPEs,
 and Meta-TYPEs.
 Data TYPEs are the means of storing data.  QTYPES can only be used in
 queries.  Meta-TYPEs designate transient data associated with a
 particular DNS message and, in some cases, can also be used in
 queries.  Thus far, data TYPEs have been assigned from 1 upward, plus
 the block from 100 through 103, and from 32,768 upward, while Q and
 Meta-TYPEs have been assigned from 255 downward except for the OPT
 Meta-RR, which is assigned TYPE 41.  There have been DNS
 implementations that made caching decisions based on the top bit of
 the bottom byte of the RRTYPE.
 There are currently three Meta-TYPEs assigned: OPT [RFC6891], TSIG
 [RFC2845], and TKEY [RFC2930].  There are currently five QTYPEs
 assigned: * (ALL/ANY), MAILA, MAILB, AXFR, and IXFR.
 Allocated RRTYPEs have mnemonics that must be completely disjoint
 from the mnemonics used for CLASSes 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 RRTYPE
 mnemonics.
                       [A-Z][A-Z0-9\-]*[A-Z0-9]
                                but not
                          (TYPE|CLASS)[0-9]*

Eastlake Best Current Practice [Page 7] RFC 6895 DNS IANA Considerations April 2013

 Considerations for the allocation of new RRTYPEs are as follows:
    Decimal
  Hexadecimal       Assignment Policy
       0
  0x0000            RRTYPE zero is used as a special indicator for the
                    SIG(0) RR [RFC2931] [RFC4034] and in other
                    circumstances and must never be allocated for
                    ordinary use.
       1 - 127
  0x0001 - 0x007F   Remaining RRTYPEs in this range are assigned for
                    data TYPEs by the DNS RRTYPE Allocation Policy as
                    specified in Section 3.1.1.
       128 - 255
  0x0080 - 0x00FF   Remaining RRTYPEs in this range are assigned for Q
                    and Meta-TYPEs by the DNS RRTYPE Allocation Policy
                    as specified in Section 3.1.1.
     256 - 61,439
  0x0100 - 0xEFFF   Remaining RRTYPEs in this range are assigned for
                    data RRTYPEs by the DNS RRTYPE Allocation Policy
                    as specified in Section 3.1.1.  (32,768 and 32,769
                    (0x8000 and 0x8001) have been assigned.)
  61,440 - 65,279
  0xF000 - 0xFEFF   Reserved for future use.  IETF Review required to
                    define use.
  65,280 - 65,534
  0xFF00 - 0xFFFE   Reserved for Private Use.
  65,535
  0xFFFF            Reserved (Standards Action)

3.1.1. DNS RRTYPE Allocation Policy

 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.

Eastlake Best Current Practice [Page 8] RFC 6895 DNS IANA Considerations April 2013

 RRTYPEs that do not meet the requirements below may nonetheless be
 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.  Before formal
    submission of an RRTYPE template, we recommend submitting it for
    community review and considering the responses in order to reduce
    the probability of initial rejection and the need for modification
    and resubmission.
 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,
    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.
 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.

Eastlake Best Current Practice [Page 9] RFC 6895 DNS IANA Considerations April 2013

3.1.2. DNS RRTYPE Expert Guidelines

 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. The request 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 wildcards, CNAME, DNAME, etc.
 4. An excessive number of RRTYPE values is being requested when the
    purpose could be met with a smaller number of values or with
    Private Use values.

3.1.3. Special Note on the OPT RR

 The OPT (OPTion) RR (RRTYPE 41) and its IANA considerations are
 specified in [RFC6891].  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.

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.

Eastlake Best Current Practice [Page 10] RFC 6895 DNS IANA Considerations April 2013

    Decimal
  Hexadecimal       Assignment Policy
       0
  0x0000            Reserved; registry closed
       1
  0x0001            AFS v3.0 Location Service [RFC1183]
       2
  0x0002            DCE/NCA root cell directory node [RFC1183]
       3 - 65,279
  0x0003 - 0xFEFF   Not allocated; registry closed
  65,280 - 65,534
  0xFF00 - 0xFFFE   Private Use
  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.
 DNS CLASSes have been little used but constitute another dimension of
 the DNS distributed database.  In particular, there is no necessary
 relationship between the namespace 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
 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.

Eastlake Best Current Practice [Page 11] RFC 6895 DNS IANA Considerations April 2013

                       [A-Z][A-Z0-9\-]*[A-Z0-9]
                                but not
                         (CLASS|TYPE)[0-9]*
 The current CLASS assignments and considerations for future
 assignments are as follows:
    Decimal
  Hexadecimal       Assignment / Policy, Reference
       0
  0x0000            Reserved; assignment requires a Standards Action.
       1
  0x0001            Internet (IN) [RFC1035]
       2
  0x0002            Available for assignment by IETF Review as a data
                    CLASS.
       3
  0x0003            Chaos (CH) [Moon1981]
       4
  0x0004            Hesiod (HS) [Dyer1987]
       5 - 127
  0x0005 - 0x007F   Available for assignment by IETF Review for data
                    CLASSes only.
     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]
     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.

Eastlake Best Current Practice [Page 12] RFC 6895 DNS IANA Considerations April 2013

  57,344 - 65,279
  0xE000 - 0xFEFF   Available for assignment to QCLASSes and
                    Meta-CLASSes only; Specification Required.
  65,280 - 65,534
  0xFF00 - 0xFFFE   Private Use
  65,535
  0xFFFF            Reserved; can only be assigned by a Standards
                    Action.

3.3. Label Considerations

 DNS NAMEs are sequences of labels [RFC1035].

3.3.1. Label Types

 At the present time, there are two categories of label types: data
 labels and compression labels.  Compression labels are pointers to
 data labels elsewhere within an RR or DNS message and are intended to
 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 uppercase and lowercase letter codes as
 matching [RFC4343].  Binary labels are bit sequences [RFC2673].  The
 Binary Label type is Historic [RFC6891].

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
 [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].

Eastlake Best Current Practice [Page 13] RFC 6895 DNS IANA Considerations April 2013

4. Security Considerations

 This document addresses IANA considerations in the allocation of
 general DNS parameters, not security.  See [RFC4033], [RFC4034], and
 [RFC4035] for secure DNS considerations.

5. IANA Considerations

 This document consists entirely of DNS IANA considerations.
 IANA has established a process for accepting Appendix A templates and
 selecting an Expert from those appointed to review such template form
 applications.  IANA forwards the template to the Expert, copying the
 applicant.  IANA archives and makes available all approved RRTYPE
 allocation templates and referred documentation (unless it is readily
 available at a stable URI).  It is the duty of the applicant to post
 the formal application template to the
 dns-rrtype-applications@ietf.org mailing list, which IANA will
 monitor.  The dnsext@ietf.org mailing list is for community
 discussion and comment.  See Section 3.1 and Appendix A for more
 details.

Eastlake Best Current Practice [Page 14] RFC 6895 DNS IANA Considerations April 2013

Appendix A. RRTYPE Allocation Template

               DNS RRTYPE PARAMETER ALLOCATION TEMPLATE
 When ready for formal consideration, this template is to be submitted
 to IANA for processing by emailing the template to dns-rrtype-
 applications@ietf.org.
 A. Submission Date:
 B.1 Submission Type:  [ ] New RRTYPE  [ ] Modification to RRTYPE
 B.2 Kind of RR:  [ ] Data RR  [ ] Meta-RR
 C. Contact Information for submitter (will be publicly posted):
    Name:                            Email Address:
    International telephone number:
    Other contact handles:
 D. Motivation for the new RRTYPE application.
    Please keep this part at a high level to inform the Expert and
    reviewers about uses of the RRTYPE.  Most reviewers will be DNS
    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: 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 subregistry in DNS
    Parameters?  If so, please indicate which registry is to be used
    or created.  If a new subregistry 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
    as an unknown RRTYPE (see [RFC3597])?
 J. Comments:

Eastlake Best Current Practice [Page 15] RFC 6895 DNS IANA Considerations April 2013

Appendix B. Changes from RFC 6195

 Dropped description of changes from RFC 5395 to [RFC6195], since
 those changes have already happened and we don't need to do them
 again.  Added description of changes from [RFC6195] to this document.
 Cut back RRTYPE Expert Review period to two weeks and eliminated the
 mandatory dnsext@ietf.org comment period.  Changed workflow
 description for RRTYPE review and allocation to correspond more
 closely to actual practice.
 Closed the AFSDB subtype registry and added an informative reference
 to [RFC5864] where the use of the AFSDB RR to locate AFS cell
 database servers is deprecated.
 Clarified IANA archiving of referenced documentation as well as
 approved RRTYPE application template.
 In the RRTYPE application template, changed the label of question "B"
 to "B.1" and added "B.2" to ask about the kind of RR.
 Added 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 RRTYPEs.
 Parenthetically listed "ANY" as well as "ALL" as a meaning for the
 "*" RRTYPE.
 Clarified that there is one DNS error number space for headers, OPT
 extended headers, TSIG RRs, and TKEY RRs.  Noted that this is
 considered to update [RFC2845] and [RFC2930].  Noted the overloading
 of error number 9 as well as 16.
 Updated references for revised versions.
 Incorporated a number of editorial changes and typo fixes.

Eastlake Best Current Practice [Page 16] RFC 6895 DNS IANA Considerations April 2013

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.
 [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.
 [RFC2930]   Eastlake 3rd, D., "Secret Key Establishment for DNS (TKEY
             RR)", RFC 2930, September 2000.
 [RFC3425]   Lawrence, D., "Obsoleting IQUERY", RFC 3425,
             November 2002.
 [RFC3597]   Gustafsson, A., "Handling of Unknown DNS Resource Record
             (RR) Types", RFC 3597, September 2003.
 [RFC4020]   Kompella, K. and A. Zinin, "Early IANA Allocation of
             Standards Track Code Points", BCP 100, RFC 4020,
             February 2005.
 [RFC4033]   Arends, R., Austein, R., Larson, M., Massey, D., and S.
             Rose, "DNS Security Introduction and Requirements",
             RFC 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.

Eastlake Best Current Practice [Page 17] RFC 6895 DNS IANA Considerations April 2013

 [RFC4635]   Eastlake 3rd, D., "HMAC SHA (Hashed Message
             Authentication Code, Secure Hash Algorithm) TSIG
             Algorithm Identifiers", RFC 4635, August 2006.
 [RFC5226]   Narten, T. and H. Alvestrand, "Guidelines for Writing an
             IANA Considerations Section in RFCs", BCP 26, RFC 5226,
             May 2008.
 [RFC6840]   Weiler, S., Ed., and D. Blacka, Ed., "Clarifications and
             Implementation Notes for DNS Security (DNSSEC)",
             RFC 6840, February 2013.
 [RFC6891]   Damas, J., Graff, M., and Vixie, P., "Extension
             Mechanisms for DNS (EDNS(0))", STD 75, RFC 6891, April
             2013.
 [US-ASCII]  American National Standards Institute (formerly United
             States of America Standards Institute), "USA Code for
             Information Interchange", ANSI X3.4-1968, 1968.
             ANSI X3.4-1968 has been replaced by newer versions with
             slight modifications, but the 1968 version remains
             definitive for the Internet.

Informative References

 [Dyer1987]  Dyer, S., and F. Hsu, "Hesiod", Project Athena Technical
             Plan - Name Service, April 1987.
 [Moon1981]  Moon, D., "Chaosnet", A.I. Memo 628, Massachusetts
             Institute of Technology Artificial Intelligence
             Laboratory, June 1981.
 [RFC1183]   Everhart, C., Mamakos, L., Ullmann, R., and P.
             Mockapetris, "New DNS RR Definitions", RFC 1183,
             October 1990.
 [RFC1591]   Postel, J., "Domain Name System Structure and
             Delegation", RFC 1591, March 1994.
 [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.

Eastlake Best Current Practice [Page 18] RFC 6895 DNS IANA Considerations April 2013

 [RFC4343]   Eastlake 3rd, D., "Domain Name System (DNS) Case
             Insensitivity Clarification", RFC 4343, January 2006.
 [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.

Acknowledgements

 Alfred Hoenes' contributions are gratefully acknowledged as are those
 by Mark Andrews, Dick Franks, and Michael Sheldon.

Author's Address

 Donald E. Eastlake 3rd
 Huawei Technologies
 155 Beaver Street
 Milford, MA  01757
 USA
 Phone: +1-508-333-2270
 EMail: d3e3e3@gmail.com

Eastlake Best Current Practice [Page 19]

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