A Top-level Domain for Private Use
draft-davies-internal-tld-01
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| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Kim Davies , Andrew McConachie | ||
| Last updated | 2024-10-18 | ||
| RFC stream | (None) | ||
| Intended RFC status | (None) | ||
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draft-davies-internal-tld-01
Network Working Group K. Davies
Internet-Draft IANA
Intended status: Informational A. McConachie
Expires: 21 April 2025 ICANN
18 October 2024
A Top-level Domain for Private Use
draft-davies-internal-tld-01
Abstract
This document describes the "internal" top-level domain for use in
private applications.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on 21 April 2025.
Copyright Notice
Copyright (c) 2024 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.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Using the ".internal" Namespace . . . . . . . . . . . . . . . 2
4. Comparisons to Similar Namespaces . . . . . . . . . . . . . . 3
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
6. Security Considerations . . . . . . . . . . . . . . . . . . . 3
7. Additional Information . . . . . . . . . . . . . . . . . . . 4
8. Informative References . . . . . . . . . . . . . . . . . . . 4
Notes (for removal before publication) . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
There are certain circumstances where private network operators may
wish to use their own domain naming scheme that is not intended to be
used or accessible by the global domain name system (DNS), such as
within closed corporate or home networks.
The "internal" top-level domain provides this purpose in the DNS.
Such domains will not resolve in the global DNS, but can be
configured within closed networks as the network operator sees fit.
It fulfils a similar purpose as private-use IP address ranges that
are set aside (e.g. [RFC1918]).
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
[BCP14] when, and only when, they appear in all capitals, as shown
here.
This document assumes familiarity with DNS terms; please see
[BCP219].
3. Using the ".internal" Namespace
Network operators have been using different names for private-use DNS
for many years. This usage has been uncoordinated and can result in
incompatibilities or harm to Internet users. For example, an
organization might choose to use a name for this purpose that has not
been assigned to them, that would later appear in the global DNS
thereby causing name collisions and undefined behavior for users.
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If an organization determines that they require a private-use DNS
namespace, they should either use sub-domains of a global DNS name
that is under their organizational and operational control, or use
the "internal" top-level domain. This document does not offer
guidance on when a network operators should choose the "internal"
top-level domain instead of a sub-domain of a global DNS name. This
decision will depend on multiple factors such as network design or
organizational needs, and is outside the scope of this publication.
4. Comparisons to Similar Namespaces
Other namespaces are reserved for similar purposes, which
superficially may seem to serve the same purpose as the "internal"
domain, but are intended for different use cases.
* The "local" namespace [RFC6762] is reserved for use with the
multicast DNS protocol. This protocol allows for resolution
between devices on a local network. This namespace does not use
typical DNS zones for name allocation, and instead uses the
multicast DNS protocol to negotiate names and resolve conflicts.
It is expected "internal" will be used for applications where
names are specified in locally-configured zones.
* The "alt" namespace [RFC9476] is reserved for contexts where
identifiers are used that may look like domain names, but do not
use the DNS protocol for resolution. This is in contrast to the
"internal" domain which is to be used with the DNS protocol, but
in limited private-use network scope.
* The "home.arpa" namespace [RFC8375] is reserved for use within
residential networks, including the Home Networking Control
Protocol [RFC7788].
5. IANA Considerations
The document requires no IANA actions. For the reasons stated above,
as the "internal" top-level domain is reserved from being used in the
global DNS it MUST NOT appear in the DNS root zone.
6. Security Considerations
While the namespace is designated for private use, there is no
guarantee that the names utilized in this namespace will not leak
into the broader Internet. Since usage may appear in log files,
email headers, and the like; users should not rely on the
confidentiality of the "internal" namespace.
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Users should also not assume the appearance of such names is
indicative of the true source of transmissions. When diagnosing
network issues, the appearance of such addresses must be interpreted
with the associated context to ascertain the private network with
which the name is being used. A private-use name can never be used
by itself to identify the origin of a communication. It is entirely
likely that many of the same names will be used for entirely
different purposes on different networks connected to the Internet.
7. Additional Information
This reservation is the result of a community deliberation on this
topic over many years, most notably [SAC113]. The SAC113 advisory
recommended the establishment of a single top-level domain for
private-use applications. This top-level domain would not be
delegated in the DNS root zone to ensure it is not resolvable in
contexts outside of a private network.
A selection process [IANA-Assessment] determined "internal" was the
best suited string given the requirement that a single string be
selected for this purpose, and subsequently reserved for this purpose
in July 2024. [ICANN-Board-Resolution]
8. Informative References
[BCP14] Best Current Practice 14,
<https://www.rfc-editor.org/info/bcp14>.
At the time of writing, this BCP comprises the following:
Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[BCP219] Best Current Practice 219,
<https://www.rfc-editor.org/info/bcp219>.
At the time of writing, this BCP comprises the following:
Hoffman, P. and K. Fujiwara, "DNS Terminology", BCP 219,
RFC 9499, DOI 10.17487/RFC9499, March 2024,
<https://www.rfc-editor.org/info/rfc9499>.
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[IANA-Assessment]
"Identification of a top-level domain for private use",
January 2024, <https://itp.cdn.icann.org/en/files/root-
system/identification-tld-private-use-24-01-2024-en.pdf>.
[ICANN-Board-Resolution]
"Reserving .INTERNAL for Private-Use Applications", July
2024, <https://www.icann.org/en/board-activities-and-
meetings/materials/approved-resolutions-special-meeting-
of-the-icann-board-29-07-2024-en#section2.a>.
[RFC1918] Rekhter, Y., Moskowitz, B., Karrenberg, D., de Groot, G.
J., and E. Lear, "Address Allocation for Private
Internets", BCP 5, RFC 1918, DOI 10.17487/RFC1918,
February 1996, <https://www.rfc-editor.org/rfc/rfc1918>.
[RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762,
DOI 10.17487/RFC6762, February 2013,
<https://www.rfc-editor.org/rfc/rfc6762>.
[RFC7788] Stenberg, M., Barth, S., and P. Pfister, "Home Networking
Control Protocol", RFC 7788, DOI 10.17487/RFC7788, April
2016, <https://www.rfc-editor.org/rfc/rfc7788>.
[RFC8375] Pfister, P. and T. Lemon, "Special-Use Domain
'home.arpa.'", RFC 8375, DOI 10.17487/RFC8375, May 2018,
<https://www.rfc-editor.org/rfc/rfc8375>.
[RFC9476] Kumari, W. and P. Hoffman, "The .alt Special-Use Top-Level
Domain", RFC 9476, DOI 10.17487/RFC9476, September 2023,
<https://www.rfc-editor.org/rfc/rfc9476>.
[SAC113] "SSAC Advisory on Private-Use TLDs", September 2020,
<https://itp.cdn.icann.org/en/files/security-and-
stability-advisory-committee-ssac-reports/sac-113-en.pdf>.
Notes (for removal before publication)
* It is currently assumed this domain should NOT be designated as a
special-use domain name at https://www.iana.org/assignments/
special-use-domain-names/ (https://www.iana.org/assignments/
special-use-domain-names/).
* I-D source is maintained at: https://github.com/kjd/draft-davies-
internal-tld (https://github.com/kjd/draft-davies-internal-tld)
Authors' Addresses
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Kim Davies
Internet Assigned Numbers Authority
Email: kim.davies@iana.org
Andrew McConachie
Internet Corporation for Assigned Names and Numbers
Email: andrew.mcconachie@icann.org
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