Scoped Interpretation of DNS Resource Records through "Underscored" Naming of Attribute Leaves
RFC 8552
| Document | Type |
RFC - Best Current Practice
(March 2019; Errata)
Also known as BCP 222
|
|
|---|---|---|---|
| Last updated | 2019-03-22 | ||
| Replaces | draft-crocker-dns-attrleaf | ||
| Stream | IETF | ||
| Formats | plain text pdf html bibtex | ||
| Reviews | |||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Benno Overeinder | ||
| Shepherd write-up | Show (last changed 2018-07-21) | ||
| IESG | IESG state | RFC 8552 (Best Current Practice) | |
| Consensus Boilerplate | Yes | ||
| Telechat date | |||
| Responsible AD | Warren Kumari | ||
| Send notices to | "Tim Wicinski" <tjw.ietf@gmail.com>, Benno Overeinder <benno@NLnetLabs.nl> | ||
| IANA | IANA review state | IANA OK - Actions Needed | |
| IANA action state | RFC-Ed-Ack | ||
Internet Engineering Task Force (IETF) D. Crocker
Request for Comments: 8552 Brandenburg InternetWorking
BCP: 222 March 2019
Category: Best Current Practice
ISSN: 2070-1721
Scoped Interpretation of DNS Resource Records through
"Underscored" Naming of Attribute Leaves
Abstract
Formally, any DNS Resource Record (RR) may occur under any domain
name. However, some services use an operational convention for
defining specific interpretations of an RRset by locating the records
in a DNS branch under the parent domain to which the RRset actually
applies. The top of this subordinate branch is defined by a naming
convention that uses a reserved node name, which begins with the
underscore character (e.g., "_name"). The underscored naming
construct defines a semantic scope for DNS record types that are
associated with the parent domain above the underscored branch. This
specification explores the nature of this DNS usage and defines the
"Underscored and Globally Scoped DNS Node Names" registry with IANA.
The purpose of this registry is to avoid collisions resulting from
the use of the same underscored name for different services.
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 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8552.
Crocker Best Current Practice [Page 1]
RFC 8552 DNS AttrLeaf March 2019
Copyright Notice
Copyright (c) 2019 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
(https://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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Underscore-Based Scoping . . . . . . . . . . . . . . . . 3
1.2. Scaling Benefits . . . . . . . . . . . . . . . . . . . . 4
1.3. Global Underscored Node Names . . . . . . . . . . . . . . 4
1.4. Interaction with DNS Wildcards . . . . . . . . . . . . . 5
1.5. History . . . . . . . . . . . . . . . . . . . . . . . . . 5
2. "Underscored and Globally Scoped DNS Node Names" Registry . . 6
3. Guidance for Registering RRset Use . . . . . . . . . . . . . 7
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
4.1. "Underscored and Globally Scoped DNS Node Names" Registry 8
4.2. Enumservices Registrations Registry . . . . . . . . . . . 11
5. Security Considerations . . . . . . . . . . . . . . . . . . . 11
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
6.1. Normative References . . . . . . . . . . . . . . . . . . 12
6.2. Informative References . . . . . . . . . . . . . . . . . 15
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 15
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction
The core Domain Name System (DNS) technical specifications ([RFC1035]
and [RFC2181]) assign no semantics to domain names or their parts,
and no constraints upon which resource record (RR) types are
permitted to be stored under particular names [RFC1035] [RFC2181].
Over time, some leaf node names, such as "www" and "ftp", have come
to imply support for particular services, but this is a matter of
operational convention rather than defined protocol semantics. This
freedom in the basic technology has permitted a wide range of
administrative and semantic policies to be used -- in parallel. DNS
data semantics have been limited to the specification of particular
resource record types on the expectation that new resource record
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RFC 8552 DNS AttrLeaf March 2019
types would be added as needed. Unfortunately, the addition of new
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