draft-ietf-dnsext-nsec-rdata-03.txt   draft-ietf-dnsext-nsec-rdata-04.txt 
DNS Extensions Working Group J. Schlyter, Ed. DNS Extensions Working Group J. Schlyter, Ed.
Updates: RFC 2535, RFC TCR (if approved) Updates: RFC 2535, RFC TCR
Expires: June 18, 2004 Expires: September 1, 2004
DNSSEC NSEC RDATA Format DNSSEC NSEC RDATA Format
draft-ietf-dnsext-nsec-rdata-03.txt draft-ietf-dnsext-nsec-rdata-04.txt
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. all provisions of Section 10 of RFC2026.
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Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved. Copyright (C) The Internet Society (2004). All Rights Reserved.
Abstract Abstract
This document defines updates the NSEC resource record RDATA format This document redefines the wire format of the "Type Bit Map" field
to cover all type codes. in the NSEC resource record RDATA format to cover the full RR type
space.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. The NSEC Resource Record . . . . . . . . . . . . . . . . . . 3 2. The NSEC Resource Record . . . . . . . . . . . . . . . . . . 3
2.1 NSEC RDATA Wire Format . . . . . . . . . . . . . . . . . . . 4 2.1 NSEC RDATA Wire Format . . . . . . . . . . . . . . . . . . . 4
2.1.1 The Next Domain Name Field . . . . . . . . . . . . . . . . . 4 2.1.1 The Next Domain Name Field . . . . . . . . . . . . . . . . . 4
2.1.2 The List of Type Bit Map(s) Field . . . . . . . . . . . . . 4 2.1.2 The List of Type Bit Map(s) Field . . . . . . . . . . . . . 4
2.1.3 Inclusion of Wildcard Names in NSEC RDATA . . . . . . . . . 5 2.1.3 Inclusion of Wildcard Names in NSEC RDATA . . . . . . . . . 5
2.2 The NSEC RR Presentation Format . . . . . . . . . . . . . . 5 2.2 The NSEC RR Presentation Format . . . . . . . . . . . . . . 5
2.3 NSEC RR Example . . . . . . . . . . . . . . . . . . . . . . 5 2.3 NSEC RR Example . . . . . . . . . . . . . . . . . . . . . . 6
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . 6 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . 6 4. Security Considerations . . . . . . . . . . . . . . . . . . 6
Normative References . . . . . . . . . . . . . . . . . . . . 6 Normative References . . . . . . . . . . . . . . . . . . . . 6
Informational References . . . . . . . . . . . . . . . . . . 7 Informational References . . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . 7 Author's Address . . . . . . . . . . . . . . . . . . . . . . 7
A. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 A. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
Intellectual Property and Copyright Statements . . . . . . . 8 Intellectual Property and Copyright Statements . . . . . . . 8
1. Introduction 1. Introduction
The NSEC [5] Resource Record (RR) is used for authenticated proof of The NSEC [5] Resource Record (RR) is used for authenticated proof of
the non-existence of DNS owner names and types. The RDATA format for the non-existence of DNS owner names and types. The NSEC RR is based
the NSEC RR, as described in RFC 2535 [2], had a limitation in that, on the NXT RR as described in RFC 2535 [2], and is similar except for
without using a yet undefined extension mechanism, the the RDATA the name and typecode. The RDATA format for the NXT RR had a
could only carry information about the existence of the first 127 limitation in that, without using a yet undefined extension
types. mechanism, the the RDATA could only carry information about the
existence of the first 127 types.
To prevent the introduction of an extension mechanism into a deployed To prevent the introduction of an extension mechanism into a deployed
base of DNSSEC aware servers and resolvers, once the first 127 type base of DNSSEC aware servers and resolvers, once the first 127 type
codes are allocated, this document redefines the wire format of the codes are allocated, this document redefines the wire format of the
"Type Bit Map" field in the NSEC RDATA to cover the full RR type "Type Bit Map" field in the NSEC RDATA to cover the full RR type
space. space.
This document introduces a new format for the type bit map. The This document introduces a new format for the type bit map. The
properties of the type bit map format are that it can cover the full properties of the type bit map format are that it can cover the full
possible range of typecodes; that it is relatively economic in the possible range of typecodes, that it is relatively economic in the
amount of space it uses for the common case of a few types with an amount of space it uses for the common case of a few types with an
owner name; that it can represent owner names with all possible type owner name, that it can represent owner names with all possible types
present in packets of approximately 8.5 kilobytes; that the present in packets of approximately 8.5 kilobytes and that the
representation is simple to implement. Efficient searching of the representation is simple to implement. Efficient searching of the
type bitmap for the presence of certain types is not a requirement. type bitmap for the presence of certain types is not a requirement.
For convenience and completeness this document presents the syntax For convenience and completeness this document presents the syntax
and semantics for the NSEC RR based on the specification in RFC 2535 and semantics for the NSEC RR based on the specification in RFC 2535
[2] and as updated by RFC TCR [5], thereby not introducing changes [2] and as updated by RFC TCR [5], thereby not introducing changes
except for the syntax of the type bit map. except for the syntax of the type bit map.
[Editors note: this is the text that is to be copied into
draft-ietf-dnssec-dnssec-records]
This document updates RFC 2535 [2] and RFC TCR [5]. This document updates RFC 2535 [2] and RFC TCR [5].
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [1]. document are to be interpreted as described in RFC 2119 [1].
2. The NSEC Resource Record 2. The NSEC Resource Record
The NSEC resource record lists two separate things: the owner name of The NSEC resource record lists two separate things: the owner name of
the next authoritative RRset in the canonical ordering of the zone, the next RRset in the canonical ordering of the zone, and the set of
and the set of RR types present at the NSEC RR's owner name. The RR types present at the NSEC RR's owner name. The complete set of
complete set of NSEC RRs in a zone both indicate which authoritative NSEC RRs in a zone both indicate which RRsets exist in a zone and
RRsets exist in a zone and also form a chain of authoritative owner also form a chain of owner names in the zone. This information is
names in the zone. This information is used to provide authenticated used to provide authenticated denial of existence for DNS data, as
denial of existence for DNS data, as described in RFC 2535 [2]. described in RFC 2535 [2].
The type value for the NSEC RR is 47. The type value for the NSEC RR is 47.
The NSEC RR RDATA format is class independent and defined for all The NSEC RR RDATA format is class independent and defined for all
classes. classes.
The NSEC RR has no special TTL requirements. The NSEC RR has no special TTL requirements.
2.1 NSEC RDATA Wire Format 2.1 NSEC RDATA Wire Format
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1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Next Domain Name / / Next Domain Name /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ List of Type Bit Map(s) / / List of Type Bit Map(s) /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2.1.1 The Next Domain Name Field 2.1.1 The Next Domain Name Field
The Next Domain Name field contains the owner name of the next The Next Domain Name field contains the owner name of the next RR in
authoritative RRset in the canonical ordering of the zone. The value the canonical ordering of the zone. The value of the Next Domain
of the Next Domain Name field in the last NSEC record in the zone is Name field in the last NSEC record in the zone is the name of the
the name of the zone apex (the owner name of the zone's SOA RR). zone apex (the owner name of the zone's SOA RR).
A sender MUST NOT use DNS name compression on the Next Domain Name
field when transmitting an NSEC RR. A receiver which receives an
NSEC RR containing a compressed Next Domain Name field SHOULD
decompress the field value.
Owner names of RRsets not authoritative for the given zone (such as
glue records) MUST NOT be listed in the Next Domain Name unless at
least one authoritative RRset exists at the same owner name.
2.1.2 The List of Type Bit Map(s) Field 2.1.2 The List of Type Bit Map(s) Field
The RR type space is split into 256 window blocks, each representing The RR type space is split into 256 window blocks, each representing
the low-order 8 bits of the 16-bit RR type space. Each block that has the low-order 8 bits of the 16-bit RR type space. Each block that has
at least one active RR type is encoded using a single octet window at least one active RR type is encoded using a single octet window
number (from 0 to 255), a single octet bitmap length (from 1 to 32) number (from 0 to 255), a single octet bitmap length (from 1 to 32)
indicating the number of octets used for the window block's bitmap, indicating the number of octets used for the window block's bitmap,
and up to 32 octets (256 bits) of bitmap. and up to 32 octets (256 bits) of bitmap.
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2.3 NSEC RR Example 2.3 NSEC RR Example
The following NSEC RR identifies the RRsets associated with The following NSEC RR identifies the RRsets associated with
alfa.example.com. and identifies the next authoritative name after alfa.example.com. and identifies the next authoritative name after
alfa.example.com. alfa.example.com.
alfa.example.com. 86400 IN NSEC host.example.com. A MX RRSIG NSEC TYPE1234 alfa.example.com. 86400 IN NSEC host.example.com. A MX RRSIG NSEC TYPE1234
The first four text fields specify the name, TTL, Class, and RR type The first four text fields specify the name, TTL, Class, and RR type
(NSEC). The entry host.example.com. is the next authoritative name (NSEC). The entry host.example.com. is the next authoritative name
after alfa.example.com. in canonical order. The A, MX, RRSIG and NSEC after alfa.example.com. in canonical order. The A, MX, RRSIG, NSEC
mnemonics indicate there are A, MX, RRSIG, NSEC and TYPE1234 RRsets and TYPE1234 mnemonics indicate there are A, MX, RRSIG, NSEC and
associated with the name alfa.example.com. TYPE1234 RRsets associated with the name alfa.example.com.
The RDATA section of the NSEC RR above would be encoded as: The RDATA section of the NSEC RR above would be encoded as:
0x04 'h' 'o' 's' 't' 0x04 'h' 'o' 's' 't'
0x07 'e' 'x' 'a' 'm' 'p' 'l' 'e' 0x07 'e' 'x' 'a' 'm' 'p' 'l' 'e'
0x03 'c' 'o' 'm' 0x00 0x03 'c' 'o' 'm' 0x00
0x00 0x06 0x40 0x01 0x00 0x00 0x00 0x03 0x00 0x06 0x40 0x01 0x00 0x00 0x00 0x03
0x04 0x1b 0x00 0x00 0x00 0x00 0x00 0x00 0x04 0x1b 0x00 0x00 0x00 0x00 0x00 0x00
0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
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RFC 2535 [2]. RFC 2535 [2].
3. IANA Considerations 3. IANA Considerations
This document introduces no new IANA considerations, because all of This document introduces no new IANA considerations, because all of
the protocol parameters used in this document have already been the protocol parameters used in this document have already been
assigned by RFC TCR [5]. assigned by RFC TCR [5].
4. Security Considerations 4. Security Considerations
The change introducted here does not affect security, since it only The update of the RDATA format and encoding does not affect the
updates the RDATA format and encoding. security of the use of NSEC RRs.
Normative References Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997. Levels", BCP 14, RFC 2119, March 1997.
[2] Eastlake, D., "Domain Name System Security Extensions", RFC [2] Eastlake, D., "Domain Name System Security Extensions", RFC
2535, March 1999. 2535, March 1999.
[3] Eastlake, D., Brunner-Williams, E. and B. Manning, "Domain Name [3] Eastlake, D., Brunner-Williams, E. and B. Manning, "Domain Name
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be obtained from the IETF Secretariat. be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive this standard. Please address the information to the IETF Executive
Director. Director.
Full Copyright Statement Full Copyright Statement
Copyright (C) The Internet Society (2003). All Rights Reserved. Copyright (C) The Internet Society (2004). All Rights Reserved.
This document and translations of it may be copied and furnished to This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of Internet organizations, except as needed for the purpose of
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