draft-ietf-dnsop-attrleaf-05.txt   draft-ietf-dnsop-attrleaf-06.txt 
dnsop D. Crocker dnsop D. Crocker
Internet-Draft Brandenburg InternetWorking Internet-Draft Brandenburg InternetWorking
Intended status: Best Current Practice March 25, 2018 Intended status: Best Current Practice March 28, 2018
Expires: September 26, 2018 Expires: September 29, 2018
DNS Scoped Data Through '_Underscore' Naming of Attribute Leaves DNS Scoped Data Through '_Underscore' Naming of Attribute Leaves
draft-ietf-dnsop-attrleaf-05 draft-ietf-dnsop-attrleaf-06
Abstract Abstract
Formally, any DNS resource record may occur for any domain name. Formally, any DNS resource record may occur for any domain name.
However some services have defined an operational convention, which However some services have defined an operational convention, which
applies to DNS leaf nodes that are under a DNS branch having one or applies to DNS leaf nodes that are under a DNS branch having one or
more reserved node names, each beginning with an underscore. The more reserved node names, each beginning with an underscore. The
underscore naming construct defines a semantic scope for DNS records underscore naming construct defines a semantic scope for DNS records
that are associated with the parent domain, above the underscored that are associated with the parent domain, above the underscored
branch. This specification explores the nature of this DNS usage and branch. This specification explores the nature of this DNS usage and
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 26, 2018. This Internet-Draft will expire on September 29, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. _Underscore Scoping . . . . . . . . . . . . . . . . . . . 2 1.1. _Underscore Scoping . . . . . . . . . . . . . . . . . . . 2
1.2. Scaling Benefits for TXT, SRV, and URI Resource Records . 3 1.2. Scaling Benefits for TXT, SRV, and URI Resource Records . 3
2. DNS Underscore Scoped Entry Registries Function . . . . . . . 4 2. DNS Underscore Scoped Entry Registries Function . . . . . . . 4
2.1. DNS Underscore Global Scoped Entry Registry Definition . 5 2.1. DNS Underscore Global Scoped Entry Registry Definition . 5
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
3.1. DNS Underscore Global ScopedEntry Registry . . . . . . . 6 3.1. DNS Underscore Global Scoped Entry Registry . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . 6 3.2. Guidance for Expert Review . . . . . . . . . . . . . . . 7
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 4. Security Considerations . . . . . . . . . . . . . . . . . . . 8
5.1. Normative References . . . . . . . . . . . . . . . . . . 6 5. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.2. References -- Informative . . . . . . . . . . . . . . . . 7 5.1. Normative References . . . . . . . . . . . . . . . . . . 8
5.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 7 5.2. References -- Informative . . . . . . . . . . . . . . . . 9
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 7 5.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 8 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 9
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction 1. Introduction
The core Domain Name System (DNS) technical specifications assign no The core Domain Name System (DNS) technical specifications assign no
semantics to domain names or their parts, and no constraints upon semantics to domain names or their parts, and no constraints upon
which resource records (RRs) are permitted to be associated with which resource records (RRs) are permitted to be associated with
particular names.[RFC1035] Over time, some leaf node names, such as particular names.[RFC1035] Over time, some leaf node names, such as
"www" and "ftp" have come to imply support for particular services, "www" and "ftp" have come to imply support for particular services,
but this is a matter of operational convention, rather than defined but this is a matter of operational convention, rather than defined
protocol semantics. This freedom in the basic technology has protocol semantics. This freedom in the basic technology has
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A given name defines a specific, constrained context for one or A given name defines a specific, constrained context for one or
more RR records, in which use of such records MUST conform to the more RR records, in which use of such records MUST conform to the
defined constraints. Within this scope, other resource records defined constraints. Within this scope, other resource records
that are not specified MAY be used. that are not specified MAY be used.
The purpose of the Underscore Global Registry is to avoid collisions The purpose of the Underscore Global Registry is to avoid collisions
resulting from the use of the same _underscore-based name, for resulting from the use of the same _underscore-based name, for
different applications. different applications.
The DNS Global Underscore Registry MUST have entries that are
unique with respect to the combination of the listed resource
record and the listed, global underscore node name (RR, _Node
Name).
Structurally, the registry is defined as a single, flat table of Structurally, the registry is defined as a single, flat table of
names that begin with _underscore. In some cases, such as for use of names that begin with _underscore. In some cases, such as for use of
an "SRV" record, the full scoping name might be multi-part, as a an "SRV" record, the full scoping name might be multi-part, as a
sequence of underscore names. Semantically, that sequence represents sequence of underscore names. Semantically, that sequence represents
a hierarchical model and it is theoretically reasonable to allow re- a hierarchical model and it is theoretically reasonable to allow re-
use of a subordinate underscore name in different underscore context; use of a subordinate underscore name in different underscore context;
that is, a subordinate name is meaningful only within the scope of that is, a subordinate name is meaningful only within the scope of
the first (top-level) underscore name. Therefore they are ignored by the first (top-level) underscore name. Therefore they are ignored by
this DNS Underscore Global Scoped Entry Registry. This registry is this DNS Underscore Global Scoped Entry Registry. This registry is
for the definition of highest-level -- ie, global -- underscore node for the definition of highest-level -- ie, global -- underscore node
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one or more subordinate levels of underscore node naming, the one or more subordinate levels of underscore node naming, the
namespaces from which names for those lower levels is chosen is namespaces from which names for those lower levels is chosen is
controlled by the parent underscore node name. Each globally- controlled by the parent underscore node name. Each globally-
registered underscore name owns a distinct, subordinate name registered underscore name owns a distinct, subordinate name
space. space.
2.1. DNS Underscore Global Scoped Entry Registry Definition 2.1. DNS Underscore Global Scoped Entry Registry Definition
A registry entry contains: A registry entry contains:
RR: Lists the RR that are defined for use within this scope.
_Node Name: Specifies a single _underscore name that defines a _Node Name: Specifies a single _underscore name that defines a
reserved name; this name is the "global" entry name for the reserved name; this name is the "global" entry name for the
scoped resource records that are associated with that name. scoped resource records that are associated with that name
RR(s): Lists the RRs that are defined for use within this scope.
References Lists specification that define the records and their use References Lists specification that define the records and their use
under this Name. The organization producing the under this Name. The organization producing the
specification retains control over the registry entry for specification retains control over the registry entry for
the _Node Name. the _Node Name.
Each RR that is to be used MUST have a separate registry entry.
3. IANA Considerations 3. IANA Considerations
Per [RFC8126], IANA is requested to establish the: Per [RFC8126], IANA is requested to establish the:
DNS Underscore Global Scoped Entry Registry DNS Underscore Global Scoped Entry Registry
This section describes actions requested of IANA. The guidance in This section describes actions requested of IANA. The guidance in
[IANA] is used. [IANA] is used.
3.1. DNS Underscore Global ScopedEntry Registry 3.1. DNS Underscore Global Scoped Entry Registry
The DNS Global Underscore Scoped Entry Registry is for DNS node names The DNS Global Underscore Scoped Entry Registry is for DNS node names
that begin with the underscore character (_) and are the first that begin with the underscore character (_) and are the first
occurrence of any names in a domain name sequence having that form; occurrence of any names in a domain name sequence having that form;
that is they are the "top" of a DNS branch and are shown as the that is they are the "top" of a DNS branch and are shown as the
right-most _underscore name -- under a "parent" domain name. right-most _underscore name -- under a "parent" domain name.
o This registry is to operate under the IANA rules for "First Come o This registry is to operate under the IANA rules for "Expert
First Served" registration. Review" registration; see Section 3.2.
o The contents of each entry in the Global registry are defined in o The contents of each entry in the Global registry are defined in
Section 2.1. Section 2.1.
o The table is to be maintained with entries sorted by the first
column (RR) and within that the second column (_Node Name).
o The required Reference for an entry MUST have a stable resolution o The required Reference for an entry MUST have a stable resolution
to the organization controlling that registry entry to the organization controlling that registry entry
Initial entries in the registry are: Initial entries in the registry are:
+-------------+-----+------------+ +------------+-----------------+------------+
| _NODE NAME | RR | REFERENCE | | RR | _NODE NAME | REFERENCE |
+-------------+-----+------------+ +------------+-----------------+------------+
| _tcp | SRV | [RFC2782] | | OPENPGPKEY | _openpgpkey | [RFC7929] |
| _udp | SRV | [RFC2782] | | SMIMEA | _smimecert | [RFC8162] |
| _sctp | SRV | [RFC2782] | | SRV | _dccp | [RFC2782] |
| _dccp | SRV | [RFC2782] | | SRV | _sctp | [RFC2782] |
| _domainkey | TXT | [RFC6376] | | SRV | _tcp | [RFC2782] |
| _spf | TXT | [RFC7208] | | SRV | _udp | [RFC2782] |
| _dmarc | TXT | [RFC7489] | | TLSA | _sctp | [RFC6698] |
| _vouch | TXT | [RFC5518] | | TLSA | _tcp | [RFC6698] |
+-------------+-----+------------+ | TLSA | _udp | [RFC6698] |
| TXT | _acme-challenge | [ACME] |
| TXT | _domainkey | [RFC6376] |
| TXT | _dmarc | [RFC7489] |
| TXT | _spf | [RFC7208] |
| TXT | _vouch | [RFC5518] |
| URI | _??? | |
+------------+-----------------+------------+
Table 1: Underscore Global Registry (initial entries) Table 1: Underscore Global Registry (initial entries)
3.2. Guidance for Expert Review
This section provides guidance for expert review of registration
requests in the of DNS Underscore Global Scoped Entry Registry.
This review is solely to determine adequacy of a requested entry
in this Registry, and does not include review of other aspects of
the document specifying that entry. For example such a document
might also contain a definition of the resource record that is
referenced by the requested entry. Any required review of that
definition is separate from the expert review required here.
The review is for the purposes of ensuring that:
o The details for creating the registry entry are sufficiently
clear, precise and complete
o The combination of the _underscore name, under which the listed
resource record is used, and the resource record, is unique in the
table
For the purposes of this Expert Review, other matters of the
specification's technical quality, adequacy or the like are outside
of scope.
4. Security Considerations 4. Security Considerations
This memo raises no security issues. This memo raises no security issues.
5. References 5. References
5.1. Normative References 5.1. Normative References
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for [ACME] Barnes, R., Hoffman-Andrews, J., McCarney, D., and J.
Writing an IANA Considerations Section in RFCs", RFC 8126, Kasten, "Automatic Certificate Management Environment
June 2017. (ACME)", I-D draft-ietf-acme-acme-11, March 2018.
5.2. References -- Informative
[IANA] M. Cotton, B. Leiba, and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", I-D
draft-leiba-cotton-iana-5226bis-11, 2017.
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.
[RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for [RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for
specifying the location of services (DNS SRV)", RFC 2782, specifying the location of services (DNS SRV)", RFC 2782,
February 2000. February 2000.
[RFC5518] Hoffman, P., Levine, J., and A. Hathcock, "Vouch By [RFC5518] Hoffman, P., Levine, J., and A. Hathcock, "Vouch By
Reference", RFC 5518, April 2009. Reference", RFC 5518, April 2009.
[RFC6335] Cotton, M., Eggert, L., Tpuch, J., Westerlund, M., and S.
Cheshire, "nternet Assigned Numbers Authority (IANA)
Procedures for the Management of the Service Name and
Transport Protocol Port Number Registry", RFC 6335, Aug
2011.
[RFC6376] Crocker, D., Hansen, T., and M. Kucherawy, "DomainKeys [RFC6376] Crocker, D., Hansen, T., and M. Kucherawy, "DomainKeys
Identified Mail (DKIM) Signatures", RFC 6376, Sept 2011. Identified Mail (DKIM) Signatures", RFC 6376, Sept 2011.
[RFC6698] Hoffman, J. and J. Schlyter, "The DNS-Based Authentication
of Named Entities (DANE) Transport Layer Security (TLS)
Protocol: TLSA", RFC 6698, August .
[RFC7208] Kitterman, S., "Sender Policy Framework (SPF) for [RFC7208] Kitterman, S., "Sender Policy Framework (SPF) for
Authorizing Use of Domains in E-Mail, Version 1", Authorizing Use of Domains in E-Mail, Version 1",
RFC 7208, April 2014. RFC 7208, April 2014.
[RFC7489] Kucherawy, M., Ed. and E. Zwicky, Ed., "Domain-based [RFC7489] Kucherawy, M., Ed. and E. Zwicky, Ed., "Domain-based
Message Authentication, Reporting, and Conformance Message Authentication, Reporting, and Conformance
(DMARC)", RFC 7489, March 2015. (DMARC)", RFC 7489, March 2015.
[RFC7929] Wouters, P., , RFC 7929, August 2016.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", RFC 8126,
June 2017.
[RFC8162] Hoffman, P. and J. Schlyter, "Using Secure DNS to
Associate Certificates with Domain Names for S/MIME",
RFC 8162, May 2017.
5.2. References -- Informative
[IANA] M. Cotton, B. Leiba, and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", RFC 8126,
June 2017.
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.
[RFC6335] Cotton, M., Eggert, L., Tpuch, J., Westerlund, M., and S.
Cheshire, "nternet Assigned Numbers Authority (IANA)
Procedures for the Management of the Service Name and
Transport Protocol Port Number Registry", RFC 6335, Aug
2011.
[RFC7553] Falstrom, P. and O. Kolkman, "The Uniform Resource [RFC7553] Falstrom, P. and O. Kolkman, "The Uniform Resource
Identifier (URI) DNS Resource Record", RFC 7553, Identifier (URI) DNS Resource Record", RFC 7553,
ISSN 2070-1721, June 2015. ISSN 2070-1721, June 2015.
5.3. URIs 5.3. URIs
[1] mailto:dnsop@ietf.org [1] mailto:dnsop@ietf.org
Appendix A. Acknowledgements Appendix A. Acknowledgements
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