draft-ietf-dnsext-5395bis-00.txt   draft-ietf-dnsext-5395bis-01.txt 
INTERNET-DRAFT Donald Eastlake 3rd INTERNET-DRAFT Donald Eastlake 3rd
Obsoletes: 5393 Stellar Switches Obsoletes: 5395 Stellar Switches
Updates: 1183, 3597 Updates: 1183, 3597
Intended status: Best Current Practice Intended status: Best Current Practice
Expires: May 9, 2011 November 10, 2010 Expires: May 10, 2011 November 11, 2010
Domain Name System (DNS) IANA Considerations Domain Name System (DNS) IANA Considerations
<draft-ietf-dnsext-5395bis-00.txt> <draft-ietf-dnsext-5395bis-01.txt>
Abstract Abstract
Internet Assigned Number Authority (IANA) parameter assignment Internet Assigned Number Authority (IANA) parameter assignment
considerations are specified for the allocation of Domain Name System considerations are specified for the allocation of Domain Name System
(DNS) resource record types, CLASSes, operation codes, error codes, (DNS) resource record types, CLASSes, operation codes, error codes,
DNS protocol message header bits, and AFSDB resource record subtypes. DNS protocol message header bits, and AFSDB resource record subtypes.
Status of This Memo Status of This Memo
skipping to change at page 2, line 8 skipping to change at page 2, line 8
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/1id-abstracts.html http://www.ietf.org/1id-abstracts.html
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html http://www.ietf.org/shadow.html
Table of Contents Table of Contents
1. Introduction............................................3 1. Introduction............................................3
1.1 Terminology............................................3 1.1. Terminology...........................................3
2. DNS Query/Response Headers..............................4 2. DNS Query/Response Headers..............................4
2.1 One Spare Bit?.........................................4 2.1. One Spare Bit?........................................4
2.2 Opcode Assignment......................................5 2.2. OpCode Assignment.....................................5
2.3 RCODE Assignment.......................................5 2.3. RCODE Assignment......................................5
3. DNS Resource Records....................................7 3. DNS Resource Records....................................7
3.1 RRTYPE IANA Considerations.............................8 3.1. RRTYPE IANA Considerations............................8
3.1.1 DNS RRTYPE Allocation Policy.........................9 3.1.1. DNS RRTYPE Allocation Policy........................9
3.1.2 DNS RRTYPE Expert Guidelines........................10 3.1.2. DNS RRTYPE Expert Guidelines.......................10
3.1.3 Special Note on the OPT RR..........................10 3.1.3. Special Note on the OPT RR.........................10
3.1.4 The AFSDB RR Subtype Field..........................10 3.1.4. The AFSDB RR Subtype Field.........................10
3.2 RR CLASS IANA Considerations..........................11 3.2. RR CLASS IANA Considerations.........................11
3.3 Label Considerations..................................13 3.3. Label Considerations.................................13
3.3.1 Label Types.........................................13 3.3.1. Label Types........................................13
3.3.2 Label Contents and Use..............................13 3.3.2. Label Contents and Use.............................13
4. Security Considerations................................14 4. Security Considerations................................14
5. IANA Considerations....................................14 5. IANA Considerations....................................14
Annex A: RRTYPE Allocation Template.......................15 Annex A: RRTYPE Allocation Template.......................15
Annex B: Changes From RFC 5395............................17 Annex B: Changes From RFC 5395............................17
Normative References......................................18 Normative References......................................18
Informative References....................................19 Informative References....................................19
1. Introduction 1. Introduction
The Domain Name System (DNS) provides replicated distributed secure The Domain Name System (DNS) provides replicated distributed secure
hierarchical databases which store "resource records" (RRs) under hierarchical databases that store "resource records" (RRs) under
domain names. DNS data is structured into CLASSes and zones which can domain names. DNS data is structured into CLASSes and zones that can
be independently maintained. See [RFC1034], [RFC1035], [RFC2136], be independently maintained. See [RFC1034], [RFC1035], [RFC2136],
[RFC2181], and [RFC4033] familiarity with which is assumed. [RFC2181], and [RFC4033], familiarity with which is assumed.
This document provides, either directly or by reference, the general This document provides, either directly or by reference, the general
IANA parameter assignment considerations applying across DNS query IANA parameter assignment considerations that apply across DNS query
and response headers and all RRs. There may be additional IANA and response headers and all RRs. There may be additional IANA
considerations that apply to only a particular RRTYPE or considerations that apply to only a particular RRTYPE or
query/response opcode. See the specific RFC defining that RRTYPE or query/response OpCode. See the specific RFC defining that RRTYPE or
query/response opcode for such considerations if they have been query/response OpCode for such considerations if they have been
defined, except for AFSDB RR considerations [RFC1183] which are defined, except for AFSDB RR considerations [RFC1183], which are
included herein. This RFC obsoletes [RFC5395]; however, the only included herein. This RFC obsoletes [RFC5395]; however, the only
significant change is the change is the mailing list xxx significant change is the change is the public review mailing list to
dnsext@ietf.org.
IANA currently maintains a web page of DNS parameters. See IANA currently maintains a web page of DNS parameters available from
<http://www.iana.org/numbers.htm>. http://www.iana.org.
1.1 Terminology 1.1. Terminology
"IETF Standards Action", "IETF Review", "Specification Required", and "IETF Standards Action", "IETF Review", "Specification Required", and
"Private Use" are as defined in [RFC5226]. "Private Use" are as defined in [RFC5226].
2. DNS Query/Response Headers 2. DNS Query/Response Headers
The header for DNS queries and responses contains field/bits in the The header for DNS queries and responses contains field/bits in the
following diagram taken from [RFC2136] and [RFC5395]: following diagram taken from [RFC2136] and [RFC5395]:
1 1 1 1 1 1 1 1 1 1 1 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ID | | ID |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|QR| Opcode |AA|TC|RD|RA| Z|AD|CD| RCODE | |QR| OpCode |AA|TC|RD|RA| Z|AD|CD| RCODE |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| QDCOUNT/ZOCOUNT | | QDCOUNT/ZOCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ANCOUNT/PRCOUNT | | ANCOUNT/PRCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| NSCOUNT/UPCOUNT | | NSCOUNT/UPCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ARCOUNT | | ARCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
The ID field identifies the query and is echoed in the response so The ID field identifies the query and is echoed in the response so
they can be matched. they can be matched.
The QR bit indicates whether the header is for a query or a response. The QR bit indicates whether the header is for a query or a response.
The AA, TC, RD, RA, AD, and CD bits are each theoretically meaningful The AA, TC, RD, RA, AD, and CD bits are each theoretically meaningful
only in queries or only in responses, depending on the bit. However, only in queries or only in responses, depending on the bit. However,
some DNS implementations copy the query header as the initial value some DNS implementations copy the query header as the initial value
of the response header without clearing bits. Thus any attempt to use of the response header without clearing bits. Thus, any attempt to
a "query" bit with a different meaning in a response or to define a use a "query" bit with a different meaning in a response or to define
query meaning for a "response" bit is dangerous given existing a query meaning for a "response" bit is dangerous, given existing
implementation. Such meanings may only be assigned by an IETF implementation. Such meanings may only be assigned by an IETF
Standards Action. Standards Action.
The unsigned integer fields query count (QDCOUNT), answer count The unsigned integer fields query count (QDCOUNT), answer count
(ANCOUNT), authority count (NSCOUNT), and additional information (ANCOUNT), authority count (NSCOUNT), and additional information
count (ARCOUNT) express the number of records in each section for all count (ARCOUNT) express the number of records in each section for all
opcodes except Update [RFC2136]. These fields have the same structure OpCodes except Update [RFC2136]. These fields have the same structure
and data type for Update but are instead the counts for the zone and data type for Update but are instead the counts for the zone
(ZOCOUNT), prerequisite (PRCOUNT), update (UPCOUNT), and additional (ZOCOUNT), prerequisite (PRCOUNT), update (UPCOUNT), and additional
information (ARCOUNT) sections. information (ARCOUNT) sections.
2.1 One Spare Bit? 2.1. One Spare Bit?
There have been ancient DNS implementations for which the Z bit being 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 on in a query meant that only a response from the primary server for
a zone is acceptable. It is believed that all current DNS a zone is acceptable. It is believed that current DNS implementations
implementations ignore this bit. ignore this bit.
Assigning a meaning to the Z bit requires an IETF Standards Action. Assigning a meaning to the Z bit requires an IETF Standards Action.
2.2 Opcode Assignment 2.2. OpCode Assignment
Currently DNS OpCodes are assigned as follows: Currently DNS OpCodes are assigned as follows:
OpCode Name Reference OpCode Name Reference
0 Query [RFC1035] 0 Query [RFC1035]
1 IQuery (Inverse Query, Obsolete) [RFC3425] 1 IQuery (Inverse Query, Obsolete) [RFC3425]
2 Status [RFC1035] 2 Status [RFC1035]
3 available for assignment 3 available for assignment
4 Notify [RFC1996] 4 Notify [RFC1996]
5 Update [RFC2136] 5 Update [RFC2136]
6-15 available for assignment 6-15 available for assignment
New OpCode assignments require an IETF Standards Action as modified New OpCode assignments require an IETF Standards Action as modified
by [RFC4020]. by [RFC4020].
2.3 RCODE Assignment 2.3. RCODE Assignment
It would appear from the DNS header above that only four bits of It would appear from the DNS header above that only four bits of
RCODE, or response/error code are available. However, RCODEs can RCODE, or response/error code, are available. However, RCODEs can
appear not only at the top level of a DNS response but also inside appear not only at the top level of a DNS response but also inside
OPT RRs [RFC2671], TSIG RRs [RFC2845], and TKEY RRs [RFC2930]. The OPT RRs [RFC2671], TSIG RRs [RFC2845], and TKEY RRs [RFC2930]. The
OPT RR provides an eight-bit extension resulting in a 12-bit RCODE OPT RR provides an 8-bit extension resulting in a 12-bit RCODE field,
field and the TSIG and TKEY RRs have a 16-bit RCODE field. and the TSIG and TKEY RRs have a 16-bit RCODE field.
Error codes appearing in the DNS header and in these three RR types Error codes appearing in the DNS header and in these three RR types
all refer to the same error code space with the single exception of all refer to the same error code space with the single exception of
error code 16 which has a different meaning in the OPT RR from its error code 16 which has a different meaning in the OPT RR from its
meaning in other contexts. See table below. meaning in other contexts. See table below.
RCODE Name Description Reference RCODE Name Description Reference
Decimal Decimal
Hexadecimal Hexadecimal
0 NoError No Error [RFC1035] 0 NoError No Error [RFC1035]
skipping to change at page 6, line 29 skipping to change at page 6, line 29
11 - 15 Available for assignment 11 - 15 Available for assignment
16 BADVERS Bad OPT Version [RFC2671] 16 BADVERS Bad OPT Version [RFC2671]
16 BADSIG TSIG Signature Failure [RFC2845] 16 BADSIG TSIG Signature Failure [RFC2845]
17 BADKEY Key not recognized [RFC2845] 17 BADKEY Key not recognized [RFC2845]
18 BADTIME Signature out of time window [RFC2845] 18 BADTIME Signature out of time window [RFC2845]
19 BADMODE Bad TKEY Mode [RFC2930] 19 BADMODE Bad TKEY Mode [RFC2930]
20 BADNAME Duplicate key name [RFC2930] 20 BADNAME Duplicate key name [RFC2930]
21 BADALG Algorithm not supported [RFC2930] 21 BADALG Algorithm not supported [RFC2930]
22 BADTRUC Bad Truncation [RFC4635] 22 BADTRUC Bad Truncation [RFC4635]
23 - 3,840 23 - 3,840
0x0017 - 0x0F00 Available for assignment 0x0017 - 0x0F00 Available for assignment
3,841 - 4,095 3,841 - 4,095
0x0F01 - 0x0FFF Private Use 0x0F01 - 0x0FFF Private Use
4,096 - 65,534 4,096 - 65,534
0x1000 - 0xFFFE Available for assignment 0x1000 - 0xFFFE Available for assignment
65,535 65,535
0xFFFF Reserved, can only be allocated by an IETF 0xFFFF Reserved, can only be allocated by an IETF
Standards Action. Standards Action.
Since it is important that RCODEs be understood for interoperability, Since it is important that RCODEs be understood for interoperability,
assignment of new RCODE listed above as "available for assignment" assignment of new RCODE listed above as "available for assignment"
requires an IETF Review. requires an IETF Review.
3. DNS Resource Records 3. DNS Resource Records
All RRs have the same top-level format shown in the figure below All RRs have the same top-level format, shown in the figure below
taken from [RFC1035]. taken from [RFC1035].
1 1 1 1 1 1 1 1 1 1 1 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| | | |
/ / / /
/ NAME / / NAME /
/ / / /
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
skipping to change at page 7, line 34 skipping to change at page 7, line 34
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| RDLENGTH | | RDLENGTH |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--| +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
/ RDATA / / RDATA /
/ / / /
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
NAME is an owner name, i.e., the name of the node to which this 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 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 in section 3.2. NAMEs consist of an ordered sequence of one or more
labels each of which has a label type [RFC1035], [RFC2671]. labels, each of which has a label type [RFC1035] [RFC2671].
TYPE is a two octet unsigned integer containing one of the RRTYPE TYPE is a 2-octet unsigned integer containing one of the RRTYPE
codes. See section 3.1. codes. See section 3.1.
CLASS is a two octet unsigned integer containing one of the RR CLASS CLASS is a 2-octet unsigned integer containing one of the RR CLASS
codes. See section 3.2. codes. See section 3.2.
TTL is a four octet (32 bit) unsigned integer that specifies, for TTL is a 4-octet (32-bit) unsigned integer that specifies, for data
data TYPEs, the number of seconds that the resource record may be TYPEs, the number of seconds that the resource record may be cached
cached before the source of the information should again be before the source of the information should again be consulted. Zero
consulted. Zero is interpreted to mean that the RR can only be used is interpreted to mean that the RR can only be used for the
for the transaction in progress. transaction in progress.
RDLENGTH is an unsigned 16-bit integer that specifies the length in RDLENGTH is an unsigned 16-bit integer that specifies the length in
octets of the RDATA field. octets of the RDATA field.
RDATA is a variable length string of octets that constitutes the RDATA is a variable length string of octets that constitutes the
resource. The format of this information varies according to the TYPE resource. The format of this information varies according to the TYPE
and in some cases the CLASS of the resource record. and, in some cases, the CLASS of the resource record.
3.1 RRTYPE IANA Considerations 3.1. RRTYPE IANA Considerations
There are three subcategories of RRTYPE numbers: data TYPEs, QTYPEs, There are three subcategories of RRTYPE numbers: data TYPEs, QTYPEs,
and Meta-TYPEs. and Meta-TYPEs.
Data TYPEs are the means of storing data. QTYPES can only be used in Data TYPEs are the means of storing data. QTYPES can only be used in
queries. Meta-TYPEs designate transient data associated with a queries. Meta-TYPEs designate transient data associated with a
particular DNS message and in some cases can also be used in queries. particular DNS message and, in some cases, can also be used in
Thus far, data TYPEs have been assigned from 1 upward plus the block queries. Thus far, data TYPEs have been assigned from 1 upward plus
from 100 through 103 and from 32,768 upward, while Q and Meta-TYPEs the block from 100 through 103 and from 32,768 upward, while Q and
have been assigned from 255 downwards except for the OPT Meta-RR Meta-TYPEs have been assigned from 255 downward except for the OPT
which is assigned TYPE 41. There have been DNS implementations which Meta-RR, which is assigned TYPE 41. There have been DNS
made caching decisions based on the top bit of the bottom byte of the implementations that made caching decisions based on the top bit of
RRTYPE. the bottom byte of the RRTYPE.
There are currently three Meta-TYPEs assigned: OPT [RFC2671], TSIG There are currently three Meta-TYPEs assigned: OPT [RFC2671], TSIG
[RFC2845], and TKEY [RFC2930]. There are currently five QTYPEs [RFC2845], and TKEY [RFC2930]. There are currently five QTYPEs
assigned: * (ALL), MAILA, MAILB, AXFR, and IXFR. assigned: * (ALL), MAILA, MAILB, AXFR, and IXFR.
RRTYPEs have mnemonics which must be completely disjoint from the RRTYPEs have mnemonics that must be completely disjoint from the
mnemonics used for CLASSes and which must match the following regular mnemonics used for CLASSes and that must match the following regular
expression: expression:
[A-Z][A-Z0-9-]* [A-Z][A-Z0-9-]*
Considerations for the allocation of new RRTYPEs are as follows: Considerations for the allocation of new RRTYPEs are as follows:
Decimal Decimal
Hexadecimal Hexadecimal
0 0
0x0000 - RRTYPE zero is used as a special indicator for the SIG RR 0x0000 - RRTYPE zero is used as a special indicator for the SIG (0)
[RFC2931], [RFC4034] and in other circumstances and must never RR [RFC2931], [RFC4034] and in other circumstances, and it
be allocated for ordinary use. must never be allocated for ordinary use.
1 - 127 1 - 127
0x0001 - 0x007F - remaining RRTYPEs in this range are assigned for 0x0001 - 0x007F - Remaining RRTYPEs in this range are assigned for
data TYPEs by the DNS RRTYPE Allocation Policy as specified in data TYPEs by the DNS RRTYPE Allocation Policy as specified
section 3.1.1. in Section 3.1.1.
128 - 255 128 - 255
0x0080 - 0x00FF - remaining RRTYPEs in this rage are assigned for Q 0x0080 - 0x00FF - Remaining RRTYPEs in this range are assigned for Q
and Meta TYPEs by the DNS RRTYPE Allocation Policy as and Meta TYPEs by the DNS RRTYPE Allocation Policy as
specified in section 3.1.1. specified in Section 3.1.1.
256 - 61,439 256 - 61,439
0x0100 - 0xEFFF - remaining RRTYPEs in this range are assigned for 0x0100 - 0xEFFF - Remaining RRTYPEs in this range are assigned for
data RRTYPEs by the DNS RRTYPE Allocation Policy as specified data RRTYPEs by the DNS RRTYPE Allocation Policy as
in section 3.1.1. (32,768 and 32,769 (0x8000 and 0x8001) have specified in Section 3.1.1. (32,768 and 32,769 (0x8000 and
been assigned.) 0x8001) have been assigned.)
61,440 - 65,279 61,440 - 65,279
0xF000 - 0xFEFF - reserved for future use. IETF Review required to 0xF000 - 0xFEFF - Reserved for future use. IETF Review required to
define use. define use.
65,280 - 65,534 65,280 - 65,534
0xFF00 - 0xFFFE - Private Use. 0xFF00 - 0xFFFE - Private Use.
65,535 65,535
0xFFFF - Reserved, can only be assigned by an IETF Standards Action. 0xFFFF - Reserved, can only be assigned by an IETF Standards Action.
3.1.1 DNS RRTYPE Allocation Policy 3.1.1. DNS RRTYPE Allocation Policy
Parameter values specified in Section 3.1 above as assigned based on Parameter values specified in Section 3.1 above, as assigned based on
DNS RRTYPE Allocation Policy are allocated by Expert Review if they DNS RRTYPE Allocation Policy, are allocated by Expert Review if they
meet the two requirements listed below. There will be a pool of a meet the two requirements listed below. There will be a pool of a
small number of Experts appointed by the IESG. Each application will small number of Experts appointed by the IESG. Each application will
be ruled on by an Expert selected by IANA. In any case where the be ruled on by an Expert selected by IANA. In any case where the
selected Expert is unavailable or states they have a conflict of selected Expert is unavailable or states they have a conflict of
interest, IANA may select another Expert from the pool. interest, IANA may select another Expert from the pool.
Some guidelines for the Experts are given in Section 3.1.2. RRTYPEs Some guidelines for the Experts are given in Section 3.1.2. RRTYPEs
that do not meet the requirements below, may nonetheless be allocated that do not meet the requirements below may nonetheless be allocated
by IETF Standards Action as modified by [RFC4020]. by IETF Standards Action as modified by [RFC4020].
1. A complete template as specified in Annex A has been posted for 1. A complete template as specified in Appendix A has been posted for
three weeks to the dnsext@ietf.org mailing list before the Expert three weeks to the dnsext@ietf.org mailing list before the Expert
Review decision. Review decision.
Note that partially completed or draft templates may be posted Note that partially completed or draft templates may be posted
directly by the applicant for comment and discussion but the directly by the applicant for comment and discussion, but the
formal posting to start the three week period is made by the formal posting to start the three week period is made by the
Expert. Expert.
2. The RR for which a RRTYPE code is being requested is either (a) a 2. The RR for which an RRTYPE code is being requested is either (a) a
data TYPE which can be handled as an Unknown RR as described in 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., [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 it is safe to simply discard RRs with that Meta-Type in queries or
responses. responses.
Note that such RRs may include additional section processing Note that such RRs may include additional section processing,
provided such processing is optional. provided such processing is optional.
No less than three weeks and no more than six weeks after a completed No less than three weeks and no more than six weeks after a completed
template has been formally posted to dnsext@ietf.org, the selected template has been formally posted to dnsext@ietf.org, the selected
Expert shall post a message, explicitly accepting or rejecting the Expert shall post a message, explicitly accepting or rejecting the
application, to IANA, dnsext@ietf.org, and the email address provided application, to IANA, dnsext@ietf.org, and the email address provided
by the applicant. If the Expert does not post such a message, the by the applicant. If the Expert does not post such a message, the
application shall be considered rejected but may be re-submitted to application shall be considered rejected but may be re-submitted to
IANA. IANA.
IANA shall maintain a public archive of approved templates. IANA shall maintain a public archive of approved templates.
3.1.2 DNS RRTYPE Expert Guidelines 3.1.2. DNS RRTYPE Expert Guidelines
The selected DNS RRTYPE Expert is required to monitor discussion of The selected DNS RRTYPE Expert is required to monitor discussion of
the proposed RRTYPE which may occur on the dnsext@ietf.org mailing the proposed RRTYPE, which may occur on the dnsext@ietf.org mailing
list and may consult with other technical experts as necessary. The list, and may consult with other technical experts as necessary. The
Expert should normally reject any RRTYPE allocation request which Expert should normally reject any RRTYPE allocation request that
meets one or more of the following criterion: meets one or more of the following criterion:
1. Was documented in a manner that was not sufficiently clear to 1. Was documented in a manner that was not sufficiently clear to
evaluate or implement. evaluate or implement.
2. Proposed RRTYPE or RRTYPEs affect DNS processing and do not meet 2. The proposed RRTYPE or RRTYPEs affect DNS processing and do not
the criteria in point 2 in Section 3.1.1 above. meet the criteria in point 2 of Section 3.1.1 above.
3. The documentation of the proposed RRTYPE or RRTYPEs is incomplete. 3. The documentation of the proposed RRTYPE or RRTYPEs is incomplete.
(Additional documentation can be provided during the public (Additional documentation can be provided during the public
comment period or by the Expert.) comment period or by the Expert.)
4. Application use as documented makes incorrect assumptions about 4. Application use as documented makes incorrect assumptions about
DNS protocol behavior, such as wild cards, CNAME, DNAME etc. DNS protocol behavior, such as wild cards, CNAME, DNAME, etc.
5. An excessive number of RRTYPE values is being requested when the 5. An excessive number of RRTYPE values is being requested when the
purpose could be met with a smaller number or with Private Use purpose could be met with a smaller number or with Private Use
values. values.
3.1.3 Special Note on the OPT RR 3.1.3. Special Note on the OPT RR
The OPT (OPTion) RR, RRTYPE 41, and its IANA Considerations are The OPT (OPTion) RR (RRTYPE 41) and its IANA Considerations are
specified in [RFC2671]. Its primary purpose is to extend the specified in [RFC2671]. Its primary purpose is to extend the
effective field size of various DNS fields including RCODE, label effective field size of various DNS fields including RCODE, label
type, OpCode, flag bits, and RDATA size. In particular, for resolvers type, OpCode, flag bits, and RDATA size. In particular, for resolvers
and servers that recognize it, it extends the RCODE field from 4 to and servers that recognize it, it extends the RCODE field from 4 to
12 bits. 12 bits.
3.1.4 The AFSDB RR Subtype Field 3.1.4. The AFSDB RR Subtype Field
The AFSDB RR [RFC1183] is a CLASS insensitive RR that has the same The AFSDB RR [RFC1183] is a CLASS-insensitive RR that has the same
RDATA field structure as the MX RR but the 16 bit unsigned integer RDATA field structure as the MX RR, but the 16-bit unsigned integer
field at the beginning of the RDATA is interpreted as a subtype as field at the beginning of the RDATA is interpreted as a subtype as
follows: follows:
Decimal Decimal
Hexadecimal Hexadecimal
0 0
0x0000 - Reserved, allocation requires IETF Standards Action. 0x0000 - Reserved; allocation requires IETF Standards Action.
1 1
0x0001 - Andrews File Service v3.0 Location Service [RFC1183]. 0x0001 - Andrews File Service v3.0 Location Service [RFC1183].
2 2
0x0002 - DCE/NCA root cell directory node [RFC1183]. 0x0002 - DCE/NCA root cell directory node [RFC1183].
3 - 65,279 3 - 65,279
0x0003 - 0xFEFF - Allocation by IETF Review. 0x0003 - 0xFEFF - Allocation by IETF Review.
65,280 - 65,534 65,280 - 65,534
0xFF00 - 0xFFFE - Private Use. 0xFF00 - 0xFFFE - Private Use.
65,535 65,535
0xFFFF - Reserved, allocation requires IETF Standards Action. 0xFFFF - Reserved; allocation requires IETF Standards Action.
3.2 RR CLASS IANA Considerations 3.2. RR CLASS IANA Considerations
There are currently two subcategories of DNS CLASSes: normal, data There are currently two subcategories of DNS CLASSes: normal, data-
containing classes and QCLASSes that are only meaningful in queries containing classes and QCLASSes that are only meaningful in queries
or updates. or updates.
DNS CLASSes have been little used but constitute another dimension of DNS CLASSes have been little used but constitute another dimension of
the DNS distributed database. In particular, there is no necessary the DNS distributed database. In particular, there is no necessary
relationship between the name space or root servers for one data relationship between the name space or root servers for one data
CLASS and those for another data CLASS. The same DNS NAME can have CLASS and those for another data CLASS. The same DNS NAME can have
completely different meanings in different CLASSes. The label types completely different meanings in different CLASSes. The label types
are the same and the null label is usable only as root in every 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 CLASS. As global networking and DNS have evolved, the IN, or
Internet, CLASS has dominated DNS use. Internet, CLASS has dominated DNS use.
As yet there has not be a requirement for "meta-CLASSes". That would As yet there has not be a requirement for "meta-CLASSes". That would
be a CLASS to designate transient data associated with a particular be a CLASS to designate transient data associated with a particular
DNS message and which might be usable in queries. However, it is DNS message, which might be usable in queries. However, it is
possible that there might be a future requirement for one or more possible that there might be a future requirement for one or more
"meta-CLASSes". "meta-CLASSes".
CLASSes have mnemonics which must be completely disjoint from the CLASSes have mnemonics that must be completely disjoint from the
mnemonics used for RRTYPEs and which must match the following regular mnemonics used for RRTYPEs and that must match the following regular
expression: expression:
[A-Z][A-Z0-9-]* [A-Z][A-Z0-9-]*
The current CLASS assignments and considerations for future The current CLASS assignments and considerations for future
assignments are as follows: assignments are as follows:
Decimal Decimal
Hexadecimal Hexadecimal
0 0
0x0000 - Reserved, assignment requires an IETF Standards Action. 0x0000 - Reserved; assignment requires an IETF Standards Action.
1 1
0x0001 - Internet (IN). 0x0001 - Internet (IN).
2 2
0x0002 - Available for assignment by IETF Review as a data CLASS. 0x0002 - Available for assignment by IETF Review as a data CLASS.
3 3
0x0003 - Chaos (CH) [Moon1981]. 0x0003 - Chaos (CH) [Moon1981].
4 4
0x0004 - Hesiod (HS) [Dyer1987]. 0x0004 - Hesiod (HS) [Dyer1987].
5 - 127 5 - 127
0x0005 - 0x007F - available for assignment by IETF Review for data 0x0005 - 0x007F - Available for assignment by IETF Review for data
CLASSes only. CLASSes only.
128 - 253 128 - 253
0x0080 - 0x00FD - available for assignment by IETF Review for 0x0080 - 0x00FD - Available for assignment by IETF Review for
QCLASSes and meta-CLASSes only. QCLASSes and meta-CLASSes only.
254 254
0x00FE - QCLASS NONE [RFC2136]. 0x00FE - QCLASS NONE [RFC2136].
255 255
0x00FF - QCLASS * (ANY) [RFC1035]. 0x00FF - QCLASS * (ANY) [RFC1035].
256 - 32,767 256 - 32,767
0x0100 - 0x7FFF - Assigned by IETF Review. 0x0100 - 0x7FFF - Assigned by IETF Review.
32,768 - 57,343 32,768 - 57,343
0x8000 - 0xDFFF - Assigned for data CLASSes only based on 0x8000 - 0xDFFF - Assigned for data CLASSes only, based on
Specification Required as defined in [RFC5226]. Specification Required as defined in [RFC5226].
57,344 - 65,279 57,344 - 65,279
0xE000 - 0xFEFF - Assigned for QCLASSes and meta-CLASSes only based 0xE000 - 0xFEFF - Assigned for QCLASSes and meta-CLASSes only, based
on Specification Required as defined in [RFC5226]. on Specification Required as defined in [RFC5226].
65,280 - 65,534 65,280 - 65,534
0xFF00 - 0xFFFE - Private Use. 0xFF00 - 0xFFFE - Private Use.
65,535 65,535
0xFFFF - Reserved, can only be assigned by an IETF Standards Action. 0xFFFF - Reserved; can only be assigned by an IETF Standards Action.
3.3 Label Considerations 3.3. Label Considerations
DNS NAMEs are sequences of labels [RFC1035]. DNS NAMEs are sequences of labels [RFC1035].
3.3.1 Label Types 3.3.1. Label Types
At the present time, there are two categories of label types, data At the present time, there are two categories of label types: data
labels and compression labels. Compression labels are pointers to labels and compression labels. Compression labels are pointers to
data labels elsewhere within an RR or DNS message and are intended to data labels elsewhere within an RR or DNS message and are intended to
shorten the wire encoding of NAMEs. shorten the wire encoding of NAMEs.
The two existing data label types are sometimes referred to as Text The two existing data label types are sometimes referred to as Text
and Binary. Text labels can, in fact, include any octet value and Binary. Text labels can, in fact, include any octet value
including zero value octets but many current uses involve only [US- including zero-value octets, but many current uses involve only [US-
ASCII]. For retrieval, Text labels are defined to treat ASCII upper ASCII]. For retrieval, Text labels are defined to treat ASCII upper
and lower case letter codes as matching [RFC4343]. Binary labels are and lower case letter codes as matching [RFC4343]. Binary labels are
bit sequences [RFC2673]. The Binary label type is Experimental bit sequences [RFC2673]. The Binary label type is Experimental
[RFC3363]. [RFC3363].
IANA considerations for label types are given in [RFC2671]. IANA considerations for label types are given in [RFC2671].
3.3.2 Label Contents and Use 3.3.2. Label Contents and Use
The last label in each NAME is "ROOT" which is the zero length label. The last label in each NAME is "ROOT", which is the zero-length
By definition, the null or ROOT label cannot be used for any other label. By definition, the null or ROOT label cannot be used for any
NAME purpose. other NAME purpose.
NAMEs are local to a CLASS. The Hesiod [Dyer1987] and Chaos NAMEs are local to a CLASS. The Hesiod [Dyer1987] and Chaos
[Moon1981] CLASSes are for essentially local use. The IN or Internet [Moon1981] CLASSes are for essentially local use. The IN, or
CLASS is thus the only DNS CLASS in global use on the Internet at Internet, CLASS is thus the only DNS CLASS in global use on the
this time. Internet at this time.
A somewhat out-of-date description of name allocation in the IN Class A somewhat out-of-date description of name allocation in the IN Class
is given in [RFC1591]. Some information on reserved top level domain is given in [RFC1591]. Some information on reserved top-level domain
names is in BCP 32 [RFC2606]. names is in BCP 32 [RFC2606].
4. Security Considerations 4. Security Considerations
This document addresses IANA considerations in the allocation of This document addresses IANA considerations in the allocation of
general DNS parameters, not security. See [RFC4033], [RFC4034], and general DNS parameters, not security. See [RFC4033], [RFC4034], and
[RFC4035] for secure DNS considerations. [RFC4035] for secure DNS considerations.
5. IANA Considerations 5. IANA Considerations
skipping to change at page 15, line 24 skipping to change at page 15, line 24
B. Submission Type: B. Submission Type:
[ ] New RRTYPE [ ] New RRTYPE
[ ] Modification to existing RRTYPE [ ] Modification to existing RRTYPE
C. Contact Information for submitter: C. Contact Information for submitter:
Name: Name:
Email Address: Email Address:
International telephone number: International telephone number:
Other contact handles: Other contact handles:
(Note: This information will be publicly posted)
(Note: This information will be publicly posted.)
D. Motivation for the new RRTYPE application? D. Motivation for the new RRTYPE application?
Please keep this part at a high level to inform the Expert and Please keep this part at a high level to inform the Expert and
reviewers about uses of the RRTYPE. Remember most reviewers reviewers about uses of the RRTYPE. Remember most reviewers
will be DNS experts that may have limited knowledge of your will be DNS experts that may have limited knowledge of your
application space. application space.
E. Description of the proposed RR type. E. Description of the proposed RR type.
This description can be provided in-line in the template, as an This description can be provided in-line in the template, as an
attachment or with a publicly available URL: attachment or with a publicly available URL:
F. What existing RRTYPE or RRTYPEs come closest to filling that F. What existing RRTYPE or RRTYPEs come closest to filling that
need and why are they unsatisfactory? need and why are they unsatisfactory?
G. What mnemonic is requested for the new RRTYPE (optional)? G. What mnemonic is requested for the new RRTYPE (optional)?
Note: this can be left blank and the mnemonic decided after the Note: this can be left blank and the mnemonic decided after the
template is accepted. template is accepted.
H. Does the requested RRTYPE make use of any existing IANA H. Does the requested RRTYPE make use of any existing IANA
Registry or require the creation of a new IANA Sub-registry and Registry or require the creation of a new IANA sub-registry in
in DNS Parameters? DNS Parameters?
If so, please indicate which registry is to be used or created. If so, please indicate which registry is to be used or created.
If a new sub-registry is needed, specify the allocation policy If a new sub-registry is needed, specify the allocation policy
for it and initial contents. Also include what the modification for it and its initial contents. Also include what the
procedures will be. modification procedures will be.
I. Does the proposal require/expect any changes in DNS I. Does the proposal require/expect any changes in DNS
servers/resolvers that prevent the new type from being servers/resolvers that prevent the new type from being
processed as an unknown RRTYPE (see [RFC3597])? processed as an unknown RRTYPE (see [RFC3597])?
J. Comments: J. Comments:
Annex B: Changes From RFC 5395 Annex B: Changes From RFC 5395
Replace "namedroppers@ops.ietf.org" with "dnsext@ietf.org". Replace "namedroppers@ops.ietf.org" with "dnsext@ietf.org".
Drop description of changes from RFC 2929 to RFC 5395 since those Drop description of changes from RFC 2929 to RFC 5395 since those
changes have already happened and we don't need to do them again. changes have already happened and we don't need to do them again.
Updates to boilerplate text. Updates to boilerplate text.
Normative References Normative References
[RFC1034] - Mockapetris, P., "Domain Names - Concepts and [RFC1034] - Mockapetris, P., "Domain names - concepts and
Facilities", STD 13, RFC 1034, November 1987. facilities", STD 13, RFC 1034, November 1987.
[RFC1035] - Mockapetris, P., "Domain Names - Implementation and [RFC1035] - Mockapetris, P., "Domain names - implementation and
Specifications", STD 13, RFC 1035, November 1987. specification", STD 13, RFC 1035, November 1987.
[RFC1996] - Vixie, P., "A Mechanism for Prompt Notification of Zone [RFC1996] - Vixie, P., "A Mechanism for Prompt Notification of Zone
Changes (DNS NOTIFY)", RFC 1996, August 1996. Changes (DNS NOTIFY)", RFC 1996, August 1996.
[RFC2136] - Vixie, P., Thomson, S., Rekhter, Y. and J. Bound, [RFC2136] - Vixie, P., Ed., Thomson, S., Rekhter, Y., and J. Bound,
"Dynamic Updates in the Domain Name System (DNS UPDATE)", RFC 2136, "Dynamic Updates in the Domain Name System (DNS UPDATE)", RFC 2136,
April 1997. April 1997.
[RFC2181] - Elz, R. and R. Bush, "Clarifications to the DNS [RFC2181] - Elz, R. and R. Bush, "Clarifications to the DNS
Specification", RFC 2181, July 1997. Specification", RFC 2181, July 1997.
[RFC2671] - Vixie, P., "Extension mechanisms for DNS (EDNS0)", RFC [RFC2671] - Vixie, P., "Extension Mechanisms for DNS (EDNS0)", RFC
2671, August 1999. 2671, August 1999.
[RFC2845] - Vixie, P., Gudmundsson, O., Eastlake, D. and B. [RFC2845] - Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B.
Wellington, "Secret Key Transaction Authentication for DNS (TSIG)", Wellington, "Secret Key Transaction Authentication for DNS (TSIG)",
RFC 2845, May 2000. RFC 2845, May 2000.
[RFC2930] - Eastlake, D., "Secret Key Establishment for DNS (TKEY [RFC2930] - Eastlake 3rd, D., "Secret Key Establishment for DNS (TKEY
RR)", September 2000. RR)", RFC 2930, September 2000.
[RFC3425] - Lawrence, D., "Obsoleting IQUERY", RFC 3425, November [RFC3425] - Lawrence, D., "Obsoleting IQUERY", RFC 3425, November
2002. 2002.
[RFC3597] - Gustafsson, A., "Handling of Unknown DNS Resource Record [RFC3597] - Gustafsson, A., "Handling of Unknown DNS Resource Record
(RR) Types", RFC 3597, September 2003. (RR) Types", RFC 3597, September 2003.
[RFC4020] - Kompella, K. and A. Zinin, "Early IANA Allocation of [RFC4020] - Kompella, K. and A. Zinin, "Early IANA Allocation of
Standards Track Code Points", BCP 100, RFC 4020, February 2005. Standards Track Code Points", BCP 100, RFC 4020, February 2005.
skipping to change at page 18, line 54 skipping to change at page 18, line 54
2005. 2005.
[RFC4034] - Arends, R., Austein, R., Larson, M., Massey, D., and S. [RFC4034] - Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Resource Records for the DNS Security Extensions", RFC 4034, Rose, "Resource Records for the DNS Security Extensions", RFC 4034,
March 2005. March 2005.
[RFC4035] - Arends, R., Austein, R., Larson, M., Massey, D., and S. [RFC4035] - Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Protocol Modifications for the DNS Security Extensions", RFC Rose, "Protocol Modifications for the DNS Security Extensions", RFC
4035, March 2005. 4035, March 2005.
[RFC4635] - D. Eastlake 3rd, "HMAC SHA (Hashed Message Authentication [RFC4635] - Eastlake 3rd, D., "HMAC SHA (Hashed Message
Code, Secure Hash Algorithm) TSIG Algorithm Identifiers". Authentication Code, Secure Hash Algorithm) TSIG Algorithm
Identifiers", RFC 4635, August 2006.
[RFC5226] - Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC5226] - Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008.
[US-ASCII] - ANSI, "USA Standard Code for Information Interchange", [US-ASCII] - ANSI, "USA Standard Code for Information Interchange",
X3.4, American National Standards Institute: New York, 1968. X3.4, American National Standards Institute: New York, 1968.
Informative References Informative References
[Dyer1987] - Dyer, S., and F. Hsu, "Hesiod", Project Athena Technical [Dyer1987] - Dyer, S., and F. Hsu, "Hesiod", Project Athena Technical
Plan - Name Service, April 1987, Plan - Name Service, April 1987.
[Moon1981] - D. Moon, "Chaosnet", A.I. Memo 628, Massachusetts [Moon1981] - Moon, D., "Chaosnet", A.I. Memo 628, Massachusetts
Institute of Technology Artificial Intelligence Laboratory, June Institute of Technology Artificial Intelligence Laboratory, June
1981. 1981.
[RFC1183] - Everhart, C., Mamakos, L., Ullmann, R., and P. [RFC1183] - Everhart, C., Mamakos, L., Ullmann, R., and P.
Mockapetris, "New DNS RR Definitions", RFC 1183, October 1990. Mockapetris, "New DNS RR Definitions", RFC 1183, October 1990.
[RFC1591] - Postel, J., "Domain Name System Structure and [RFC1591] - Postel, J., "Domain Name System Structure and
Delegation", RFC 1591, March 1994. Delegation", RFC 1591, March 1994.
[RFC2606] - Eastlake, D. and A. Panitz, "Reserved Top Level DNS [RFC2606] - Eastlake 3rd, D. and A. Panitz, "Reserved Top Level DNS
Names", RFC 2606, June 1999. Names", BCP 32, RFC 2606, June 1999.
[RFC2673] - Crawford, M., "Binary Labels in the Domain Name System", [RFC2673] - Crawford, M., "Binary Labels in the Domain Name System",
RFC 2673, August 1999. RFC 2673, August 1999.
[RFC2931] - Eastlake, E., "DNS Request and Transaction Signatures ( [RFC2931] - Eastlake 3rd, E., "DNS Request and Transaction Signatures
SIG(0)s )", RFC 2931, September 2000. ( SIG(0)s )", RFC 2931, September 2000.
[RFC3363] - Bush, R., Durand, A., Fink, B., Gudmundsson, O., and T. [RFC3363] - Bush, R., Durand, A., Fink, B., Gudmundsson, O., and T.
Hain, "Representing Internet Protocol version 6 (IPv6) Addresses in Hain, "Representing Internet Protocol version 6 (IPv6) Addresses in
the Domain Name System (DNS)", RFC 3363, August 2002. the Domain Name System (DNS)", RFC 3363, August 2002.
[RFC4343] - Eastlake, D., "Domain Name System (DNS) Case [RFC4343] - Eastlake, D., "Domain Name System (DNS) Case
Insensitivity Clarification", RFC 4343, December 2005. Insensitivity Clarification", RFC 4343, December 2005.
[RFC5395] - Eastlake 3rd, D., "Domain Name System (DNS) IANA [RFC5395] - Eastlake 3rd, D., "Domain Name System (DNS) IANA
Considerations", BCP 42, RFC 5395, November 2008. Considerations", BCP 42, RFC 5395, November 2008.
 End of changes. 104 change blocks. 
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