IETF L. Chapin, Ed.
Internet-Draft Interisle Consulting Group
Intended status: Standards Track M. McFadden, Ed.
Expires: October 17, 2014 InterConnect Communications Ltd
April 15, 2014
Additional Reserved Top Level Domains
draft-chapin-additional-reserved-tlds-01
Abstract
The Internet Domain Name System (DNS) defines a tree of names
starting with root, ".", immediately below which are top level domain
(TLD) names such as ".com" and ".us". In June 1999 [RFC2606]
reserved a small number of TLD names for use in documentation
examples, private testing, experiments, and other circumstances in
which it is desirable to avoid conflict with current or future actual
TLD names in the DNS.
There has been significant evolution of Internet engineering and
operation practices since [RFC2606] was published. In February 2013
[RFC6761] defined criteria and procedures for reserving a domain name
for special use, and established an IANA registry for such names.
This document reserves six domain name labels for special use in
accordance with the criteria and procedures of [RFC6761]:
localdomain, domain, lan, home, corp, and mail.
It is important to note that TLD names may be reserved, in other
contexts, for policy, political, or other reasons that are distinct
from the IETF's concern with Internet engineering and operations.
This document reserves TLD names only for operational and engineering
reasons.
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
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
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This Internet-Draft will expire on October 17, 2014.
Copyright Notice
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document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 4
3. New top-level domain name reservations . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
5.1. Domain Name Reservation Considerations for localdomain . 6
5.1.1. Users . . . . . . . . . . . . . . . . . . . . . . . . 6
5.1.2. Application Software . . . . . . . . . . . . . . . . 7
5.1.3. Name Resolution APSs and Libraries . . . . . . . . . 7
5.1.4. Caching DNS Servers . . . . . . . . . . . . . . . . . 7
5.1.5. Authoritative DNS Servers . . . . . . . . . . . . . . 7
5.1.6. DNS Server Operators . . . . . . . . . . . . . . . . 8
5.1.7. DNS Registries/Registrars . . . . . . . . . . . . . . 8
5.2. Domain Name Reservation Considerations for domain . . . . 9
5.2.1. Users . . . . . . . . . . . . . . . . . . . . . . . . 9
5.2.2. Application Software . . . . . . . . . . . . . . . . 9
5.2.3. Name Resolution APSs and Libraries . . . . . . . . . 9
5.2.4. Caching DNS Servers . . . . . . . . . . . . . . . . . 9
5.2.5. Authoritative DNS Servers . . . . . . . . . . . . . . 10
5.2.6. DNS Server Operators . . . . . . . . . . . . . . . . 10
5.2.7. DNS Registries/Registrars . . . . . . . . . . . . . . 10
5.3. Domain Name Reservation Considerations for lan . . . . . 11
5.3.1. Users . . . . . . . . . . . . . . . . . . . . . . . . 11
5.3.2. Application Software . . . . . . . . . . . . . . . . 11
5.3.3. Name Resolution APSs and Libraries . . . . . . . . . 11
5.3.4. Caching DNS Servers . . . . . . . . . . . . . . . . . 11
5.3.5. Authoritative DNS Servers . . . . . . . . . . . . . . 12
5.3.6. DNS Server Operators . . . . . . . . . . . . . . . . 12
5.3.7. DNS Registries/Registrars . . . . . . . . . . . . . . 12
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5.4. Domain Name Reservation Considerations for home . . . . . 13
5.4.1. Users . . . . . . . . . . . . . . . . . . . . . . . . 13
5.4.2. Application Software . . . . . . . . . . . . . . . . 13
5.4.3. Name Resolution APSs and Libraries . . . . . . . . . 13
5.4.4. Caching DNS Servers . . . . . . . . . . . . . . . . . 14
5.4.5. Authoritative DNS Servers . . . . . . . . . . . . . . 14
5.4.6. DNS Server Operators . . . . . . . . . . . . . . . . 14
5.4.7. DNS Registries/Registrars . . . . . . . . . . . . . . 15
5.5. Domain Name Reservation Considerations for corp . . . . . 15
5.5.1. Users . . . . . . . . . . . . . . . . . . . . . . . . 15
5.5.2. Application Software . . . . . . . . . . . . . . . . 15
5.5.3. Name Resolution APSs and Libraries . . . . . . . . . 15
5.5.4. Caching DNS Servers . . . . . . . . . . . . . . . . . 16
5.5.5. Authoritative DNS Servers . . . . . . . . . . . . . . 16
5.5.6. DNS Server Operators . . . . . . . . . . . . . . . . 16
5.5.7. DNS Registries/Registrars . . . . . . . . . . . . . . 17
5.6. Domain Name Reservation Considerations for mail . . . . . 17
5.6.1. Users . . . . . . . . . . . . . . . . . . . . . . . . 17
5.6.2. Application Software . . . . . . . . . . . . . . . . 17
5.6.3. Name Resolution APSs and Libraries . . . . . . . . . 18
5.6.4. Caching DNS Servers . . . . . . . . . . . . . . . . . 18
5.6.5. Authoritative DNS Servers . . . . . . . . . . . . . . 18
5.6.6. DNS Server Operators . . . . . . . . . . . . . . . . 18
5.6.7. DNS Registries/Registrars . . . . . . . . . . . . . . 19
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 19
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 19
8.1. Normative References . . . . . . . . . . . . . . . . . . 19
8.2. Informative References . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20
1. Introduction
The Internet Domain Name System is documented in [RFC1034],
[RFC1035], [RFC1591] and numerous additional Requests for Comment.
It defines a tree of names starting with root, ".", immediately below
which are top level domain names such as ".com" and ".us". Below top
level domain names there are normally additional levels of names.
[RFC2606] reserves a small number of TLD names which can be used for
private testing of existing DNS related code, examples in
documentation, DNS related experimentation, invalid DNS names, or
other similar uses without fear of conflicts with current or future
actual top-level domain names in the global DNS. [RFC2606] also
notes that the Internet Assigned Numbers Authority (IANA) reserves
the label "example" at the second level below the TLDs .com, .net,
and .org.
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Since [RFC2606] was published in 1999, Internet engineering and
operation practices have evolved in ways that led to the publication
in February 2013 of [RFC6761], which defined criteria and procedures
for reserving a domain name for special use and established an IANA
registry to which additional reserved special use names might be
added as new requirements arose.
This document follows [RFC6761] to add six reserved top-level domain
name labels to the IANA special-use names registry. It is prompted
by the impending advent of new TLDs which might, in the absence of
the reservations for which this document provides, introduce TLD
labels that could create engineering and operational problems for
root server operators and other DNS infrastructure providers.
It is important to note that TLD names may be reserved, in other
contexts, for policy, political, or other reasons that are distinct
from the IETF's concern with Internet engineering and operations.
This document reserves TLD names only for operational and engineering
reasons.
2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
In this document, these words will appear with that interpretation
only when in ALL CAPS. Lower case uses of these words are not to be
interpreted as carrying [RFC2119] significance.
3. New top-level domain name reservations
In its report [SAC045] of a quantitative study of queries to the DNS
root servers entitled "Invalid Top Level Domain Queries at the Root
Level of the Domain Name System" [SAC045] ICANN's Security and
Stability Advisory Committee "calls attention to the potential
problems that may arise should a new TLD applicant use a string that
has been seen with measurable (and meaningful) frequency in a query
for resolution by the root system and the root system has previously
generated a response."
Of particular concern is the case in which a string "has been queried
and a root name server has responded to the query with a non-existent
domain (NXDOMAIN) result, i.e., the string has not been delegated but
has been queried." [SAC045] reports the results of a CAIDA
measurement study [RSSAC_DNS] which found that "NXDOMAIN responses
account for more than 25 percent of the total responses from root
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name servers observed in the study, and the top ten such strings
account for 10 percent of the total query load."
[SAC045] describes in detail the engineering and operational problems
that would ensue from the delegation, as new valid TLD names, of
previously invalid labels that have frequently appeared in queries to
the root: "If the [new TLD label] were to be approved and the TLD
included in the root zone, queries to the root level of the DNS for a
string that hitherto returned NXDOMAIN would begin to return positive
responses containing name servers of the new TLD."
Recommendation (2) of [SAC045] calls for the community to develop
principles for "prohibiting the delegation of additional strings to
those already identified in [RFC2606]." As the first step in that
process, based on the data reported by [SAC045], this document adds
to the list of names that may not be used for top-level domains the
following labels:
o domain
o lan
o home
o corp
o localdomain
These five top-level domain labels are to be added to the "Special-
Use Domain Names" registry created by [RFC6761], as described in the
IANA Considerations section of this document.
In addition, [SAC062] describes the risks associated with delegating
a name in the root of the public DNS that is also used in privately
defined namespaces (in which it is also syntactically valid). Users,
software, or other functions in the private domain may confuse the
private and public instances of the same name. This risk, referred
to as "name collision," results in potential harm to enterprise
networks that use previously undelegated names at the root of a
private namespace when the name is delegated in the public root.
Research conducted by Interisle Consulting Group [INTERISLE]
indicates that another name, in addition to those identified by
[SAC045], presents a particularly high risk of name collision. This
document therefore also adds the following string to the "Special-Use
Domain Names" registry:
o mail
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Further resesarch, conducted by JAS Advisors on behalf of ICANN
[JAS_MITIGATION] shows that the names .corp, .home and .mail are
clear and significant risks for name collision. In that report the
following recommendation is made: "The TLDs .corp, .home, and .mail
be permanently reserved for internal use and receive RFC 1918-like
protection/treatment, potentially via RFC 6761."
4. Security Considerations
The name reservations specified in this document are intended to
reduce the risk of harmful collision between names that are in well-
established common use as TLDs in private namespaces and
syntactically identical names that could otherwise be delegated as
TLDs in the global DNS.
The security concerns associated with name collision are well
presented in [SAC045], [SAC062], the Interisle report [INTERISLE],
and the ICANN report "Name Collision Identification and Mitigation
for IT Professionals" [ICANN_MITIGATION].
5. IANA Considerations
This document specifies six new labels to be added to the "Special-
Use Domain Names" registry maintained by IANA pursuant to [RFC6761].
The labels are to be added to the registry in the following way:
Name Reference
----------------+---------------
localdomain [ RFC-to-be ]
domain [ RFC-to-be ]
lan [ RFC-to-be ]
home [ RFC-to-be ]
corp [ RFC-to-be ]
mail [ RFC-to-be ]
Figure 1
5.1. Domain Name Reservation Considerations for localdomain
5.1.1. Users
Are human users expected to recognize these names as special and use
them differently? In what way?
The reservations provided in this document are intended to reduce
spurious queries at the root of the DNS and avoid potential
collisions between resolutions of names in private name spaces and
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the public DNS. Users do not have to know that these names are
special.
5.1.2. Application Software
Are writers of application software expected to make their software
recognize these names as special and treat them differently? In what
way? (For example, if a human user enters such a name, should the
application software reject it with an error message?)
These names are being added to the Special-Use Domain Name registry,
in part, because some application software implementations have long
used these names for special purposes in private networks.
Developers of new applications do not need to filter or test for the
names. Instead, the intent is to reserve the names for local use and
avoid unnecessary queries in the public DNS.
5.1.3. Name Resolution APSs and Libraries
Are writers of name resolution APIs and libraries expected to make
their software recognize these names as special and treat them
differently? If so, how?
Authors of name resolution APIs and libraries SHOULD restrict these
names to local resolution and SHOULD NOT allow queries for strings
that use these Special-Use Domain Names to be forwarded to the public
DNS for resolution.
5.1.4. Caching DNS Servers
Are developers of caching domain name servers expected to make their
implementations recognize these names as special and treat them
differently? If so, how?
Authors of caching domain name server software SHOULD restrict these
names to local resolution and SHOULD NOT allow queries for strings
that use these Special-Use Domain Names to be forwarded to the public
DNS for resolution.
5.1.5. Authoritative DNS Servers
Are developers of authoritative domain name servers expected to make
their implementations recognize these names as special and treat them
differently? If so, how?
Authors of authoritative domain name server software SHOULD restrict
these names to local resolution and SHOULD NOT allow queries for
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strings that use these Special-Use Domain Names to be forwarded to
the public DNS for resolution.
5.1.6. DNS Server Operators
Does this reserved Special-Use Domain Name have any potential impact
on DNS server operators? If they try to configure their
authoritative DNS server as authoritative for this reserved name,
will compliant name server software reject it as invalid? Do DNS
server operators need to know about that and understand why? Even if
the name server software doesn't prevent them from using this
reserved name, are there other ways that it may not work as expected,
of which the DNS server operator should be aware?
The intent of the reservations in this IANA Considerations section is
to prevent spurious and potentially problematic queries from
appearing in the public DNS. DNS server operators SHOULD always
treat strings with the Special-Use Domain Names in section 5 as names
for local resolution.
Since these strings are intended to have local use, it is quite
possible that DNS operators would configure an authoritative DNS
server as authoritative for these reserved names in a private
network. This would be consistent with the goal of having these
names resolved locally rather than on the public Internet. Compliant
name server software MUST NOT reject these names as invalid.
Instead, name server software SHOULD allow for local resolution of
the name and SHOULD not transmit a query for resolution into the
public DNS.
5.1.7. DNS Registries/Registrars
How should DNS Registries/Registrars treat requests to register this
reserved domain name? Should such requests be denied? Should such
requests be allowed, but only to a specially-designated entity? (For
example, the name "www.example.org" is reserved for documentation
examples and is not available for registration; however, the name is
in fact registered; and there is even a web site at that name, which
states circularly that the name is reserved for use in documentation
and cannot be registered!)
Requests to register any names added to the Special-Use Domain Name
registry as part of the IANA Considerations section of this document
MUST be denied.
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5.2. Domain Name Reservation Considerations for domain
5.2.1. Users
Are human users expected to recognize these names as special and use
them differently? In what way?
The reservations provided in this document are intended to reduce
spurious queries at the root of the DNS and avoid potential
collisions between resolutions of names in private name spaces and
the public DNS. Users do not have to know that these names are
special.
5.2.2. Application Software
Are writers of application software expected to make their software
recognize these names as special and treat them differently? In what
way? (For example, if a human user enters such a name, should the
application software reject it with an error message?)
These names are being added to the Special-Use Domain Name registry,
in part, because some application software implementations have long
used these names for special purposes in private networks.
Developers of new applications do not need to filter or test for the
names. Instead, the intent is to reserve the names for local use and
avoid unnecessary queries in the public DNS.
5.2.3. Name Resolution APSs and Libraries
Are writers of name resolution APIs and libraries expected to make
their software recognize these names as special and treat them
differently? If so, how?
Authors of name resolution APIs and libraries SHOULD restrict these
names to local resolution and SHOULD NOT allow queries for strings
that use these Special-Use Domain Names to be forwarded to the public
DNS for resolution.
5.2.4. Caching DNS Servers
Are developers of caching domain name servers expected to make their
implementations recognize these names as special and treat them
differently? If so, how?
Authors of caching domain name server software SHOULD restrict these
names to local resolution and SHOULD NOT allow queries for strings
that use these Special-Use Domain Names to be forwarded to the public
DNS for resolution.
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5.2.5. Authoritative DNS Servers
Are developers of authoritative domain name servers expected to make
their implementations recognize these names as special and treat them
differently? If so, how?
Authors of authoritative domain name server software SHOULD restrict
these names to local resolution and SHOULD NOT allow queries for
strings that use these Special-Use Domain Names to be forwarded to
the public DNS for resolution.
5.2.6. DNS Server Operators
Does this reserved Special-Use Domain Name have any potential impact
on DNS server operators? If they try to configure their
authoritative DNS server as authoritative for this reserved name,
will compliant name server software reject it as invalid? Do DNS
server operators need to know about that and understand why? Even if
the name server software doesn't prevent them from using this
reserved name, are there other ways that it may not work as expected,
of which the DNS server operator should be aware?
The intent of the reservations in this IANA Considerations section is
to prevent spurious and potentially problematic queries from
appearing in the public DNS. DNS server operators SHOULD always
treat strings with the Special-Use Domain Names in section 5 as names
for local resolution.
Since these strings are intended to have local use, it is quite
possible that DNS operators would configure an authoritative DNS
server as authoritative for these reserved names in a private
network. This would be consistent with the goal of having these
names resolved locally rather than on the public Internet. Compliant
name server software MUST NOT reject these names as invalid.
Instead, name server software SHOULD allow for local resolution of
the name and SHOULD not transmit a query for resolution into the
public DNS.
5.2.7. DNS Registries/Registrars
How should DNS Registries/Registrars treat requests to register this
reserved domain name? Should such requests be denied? Should such
requests be allowed, but only to a specially-designated entity? (For
example, the name "www.example.org" is reserved for documentation
examples and is not available for registration; however, the name is
in fact registered; and there is even a web site at that name, which
states circularly that the name is reserved for use in documentation
and cannot be registered!)
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Requests to register any names added to the Special-Use Domain Name
registry as part of the IANA Considerations section of this document
MUST be denied.
5.3. Domain Name Reservation Considerations for lan
5.3.1. Users
Are human users expected to recognize these names as special and use
them differently? In what way?
The reservations provided in this document are intended to reduce
spurious queries at the root of the DNS and avoid potential
collisions between resolutions of names in private name spaces and
the public DNS. Users do not have to know that these names are
special.
5.3.2. Application Software
Are writers of application software expected to make their software
recognize these names as special and treat them differently? In what
way? (For example, if a human user enters such a name, should the
application software reject it with an error message?)
These names are being added to the Special-Use Domain Name registry,
in part, because some application software implementations have long
used these names for special purposes in private networks.
Developers of new applications do not need to filter or test for the
names. Instead, the intent is to reserve the names for local use and
avoid unnecessary queries in the public DNS.
5.3.3. Name Resolution APSs and Libraries
Are writers of name resolution APIs and libraries expected to make
their software recognize these names as special and treat them
differently? If so, how?
Authors of name resolution APIs and libraries SHOULD restrict these
names to local resolution and SHOULD NOT allow queries for strings
that use these Special-Use Domain Names to be forwarded to the public
DNS for resolution.
5.3.4. Caching DNS Servers
Are developers of caching domain name servers expected to make their
implementations recognize these names as special and treat them
differently? If so, how?
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Authors of caching domain name server software SHOULD restrict these
names to local resolution and SHOULD NOT allow queries for strings
that use these Special-Use Domain Names to be forwarded to the public
DNS for resolution.
5.3.5. Authoritative DNS Servers
Are developers of authoritative domain name servers expected to make
their implementations recognize these names as special and treat them
differently? If so, how?
Authors of authoritative domain name server software SHOULD restrict
these names to local resolution and SHOULD NOT allow queries for
strings that use these Special-Use Domain Names to be forwarded to
the public DNS for resolution.
5.3.6. DNS Server Operators
Does this reserved Special-Use Domain Name have any potential impact
on DNS server operators? If they try to configure their
authoritative DNS server as authoritative for this reserved name,
will compliant name server software reject it as invalid? Do DNS
server operators need to know about that and understand why? Even if
the name server software doesn't prevent them from using this
reserved name, are there other ways that it may not work as expected,
of which the DNS server operator should be aware?
The intent of the reservations in this IANA Considerations section is
to prevent spurious and potentially problematic queries from
appearing in the public DNS. DNS server operators SHOULD always
treat strings with the Special-Use Domain Names in section 5 as names
for local resolution.
Since these strings are intended to have local use, it is quite
possible that DNS operators would configure an authoritative DNS
server as authoritative for these reserved names in a private
network. This would be consistent with the goal of having these
names resolved locally rather than on the public Internet. Compliant
name server software MUST NOT reject these names as invalid.
Instead, name server software SHOULD allow for local resolution of
the name and SHOULD not transmit a query for resolution into the
public DNS.
5.3.7. DNS Registries/Registrars
How should DNS Registries/Registrars treat requests to register this
reserved domain name? Should such requests be denied? Should such
requests be allowed, but only to a specially-designated entity? (For
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example, the name "www.example.org" is reserved for documentation
examples and is not available for registration; however, the name is
in fact registered; and there is even a web site at that name, which
states circularly that the name is reserved for use in documentation
and cannot be registered!)
Requests to register any names added to the Special-Use Domain Name
registry as part of the IANA Considerations section of this document
MUST be denied.
5.4. Domain Name Reservation Considerations for home
5.4.1. Users
Are human users expected to recognize these names as special and use
them differently? In what way?
The reservations provided in this document are intended to reduce
spurious queries at the root of the DNS and avoid potential
collisions between resolutions of names in private name spaces and
the public DNS. Users do not have to know that these names are
special.
5.4.2. Application Software
Are writers of application software expected to make their software
recognize these names as special and treat them differently? In what
way? (For example, if a human user enters such a name, should the
application software reject it with an error message?)
These names are being added to the Special-Use Domain Name registry,
in part, because some application software implementations have long
used these names for special purposes in private networks.
Developers of new applications do not need to filter or test for the
names. Instead, the intent is to reserve the names for local use and
avoid unnecessary queries in the public DNS.
5.4.3. Name Resolution APSs and Libraries
Are writers of name resolution APIs and libraries expected to make
their software recognize these names as special and treat them
differently? If so, how?
Authors of name resolution APIs and libraries SHOULD restrict these
names to local resolution and SHOULD NOT allow queries for strings
that use these Special-Use Domain Names to be forwarded to the public
DNS for resolution.
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5.4.4. Caching DNS Servers
Are developers of caching domain name servers expected to make their
implementations recognize these names as special and treat them
differently? If so, how?
Authors of caching domain name server software SHOULD restrict these
names to local resolution and SHOULD NOT allow queries for strings
that use these Special-Use Domain Names to be forwarded to the public
DNS for resolution.
5.4.5. Authoritative DNS Servers
Are developers of authoritative domain name servers expected to make
their implementations recognize these names as special and treat them
differently? If so, how?
Authors of authoritative domain name server software SHOULD restrict
these names to local resolution and SHOULD NOT allow queries for
strings that use these Special-Use Domain Names to be forwarded to
the public DNS for resolution.
5.4.6. DNS Server Operators
Does this reserved Special-Use Domain Name have any potential impact
on DNS server operators? If they try to configure their
authoritative DNS server as authoritative for this reserved name,
will compliant name server software reject it as invalid? Do DNS
server operators need to know about that and understand why? Even if
the name server software doesn't prevent them from using this
reserved name, are there other ways that it may not work as expected,
of which the DNS server operator should be aware?
The intent of the reservations in this IANA Considerations section is
to prevent spurious and potentially problematic queries from
appearing in the public DNS. DNS server operators SHOULD always
treat strings with the Special-Use Domain Names in section 5 as names
for local resolution.
Since these strings are intended to have local use, it is quite
possible that DNS operators would configure an authoritative DNS
server as authoritative for these reserved names in a private
network. This would be consistent with the goal of having these
names resolved locally rather than on the public Internet. Compliant
name server software MUST NOT reject these names as invalid.
Instead, name server software SHOULD allow for local resolution of
the name and SHOULD not transmit a query for resolution into the
public DNS.
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5.4.7. DNS Registries/Registrars
How should DNS Registries/Registrars treat requests to register this
reserved domain name? Should such requests be denied? Should such
requests be allowed, but only to a specially-designated entity? (For
example, the name "www.example.org" is reserved for documentation
examples and is not available for registration; however, the name is
in fact registered; and there is even a web site at that name, which
states circularly that the name is reserved for use in documentation
and cannot be registered!)
Requests to register any names added to the Special-Use Domain Name
registry as part of the IANA Considerations section of this document
MUST be denied.
5.5. Domain Name Reservation Considerations for corp
5.5.1. Users
Are human users expected to recognize these names as special and use
them differently? In what way?
The reservations provided in this document are intended to reduce
spurious queries at the root of the DNS and avoid potential
collisions between resolutions of names in private name spaces and
the public DNS. Users do not have to know that these names are
special.
5.5.2. Application Software
Are writers of application software expected to make their software
recognize these names as special and treat them differently? In what
way? (For example, if a human user enters such a name, should the
application software reject it with an error message?)
These names are being added to the Special-Use Domain Name registry,
in part, because some application software implementations have long
used these names for special purposes in private networks.
Developers of new applications do not need to filter or test for the
names. Instead, the intent is to reserve the names for local use and
avoid unnecessary queries in the public DNS.
5.5.3. Name Resolution APSs and Libraries
Are writers of name resolution APIs and libraries expected to make
their software recognize these names as special and treat them
differently? If so, how?
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Authors of name resolution APIs and libraries SHOULD restrict these
names to local resolution and SHOULD NOT allow queries for strings
that use these Special-Use Domain Names to be forwarded to the public
DNS for resolution.
5.5.4. Caching DNS Servers
Are developers of caching domain name servers expected to make their
implementations recognize these names as special and treat them
differently? If so, how?
Authors of caching domain name server software SHOULD restrict these
names to local resolution and SHOULD NOT allow queries for strings
that use these Special-Use Domain Names to be forwarded to the public
DNS for resolution.
5.5.5. Authoritative DNS Servers
Are developers of authoritative domain name servers expected to make
their implementations recognize these names as special and treat them
differently? If so, how?
Authors of authoritative domain name server software SHOULD restrict
these names to local resolution and SHOULD NOT allow queries for
strings that use these Special-Use Domain Names to be forwarded to
the public DNS for resolution.
5.5.6. DNS Server Operators
Does this reserved Special-Use Domain Name have any potential impact
on DNS server operators? If they try to configure their
authoritative DNS server as authoritative for this reserved name,
will compliant name server software reject it as invalid? Do DNS
server operators need to know about that and understand why? Even if
the name server software doesn't prevent them from using this
reserved name, are there other ways that it may not work as expected,
of which the DNS server operator should be aware?
The intent of the reservations in this IANA Considerations section is
to prevent spurious and potentially problematic queries from
appearing in the public DNS. DNS server operators SHOULD always
treat strings with the Special-Use Domain Names in section 5 as names
for local resolution.
Since these strings are intended to have local use, it is quite
possible that DNS operators would configure an authoritative DNS
server as authoritative for these reserved names in a private
network. This would be consistent with the goal of having these
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names resolved locally rather than on the public Internet. Compliant
name server software MUST NOT reject these names as invalid.
Instead, name server software SHOULD allow for local resolution of
the name and SHOULD not transmit a query for resolution into the
public DNS.
5.5.7. DNS Registries/Registrars
How should DNS Registries/Registrars treat requests to register this
reserved domain name? Should such requests be denied? Should such
requests be allowed, but only to a specially-designated entity? (For
example, the name "www.example.org" is reserved for documentation
examples and is not available for registration; however, the name is
in fact registered; and there is even a web site at that name, which
states circularly that the name is reserved for use in documentation
and cannot be registered!)
Requests to register any names added to the Special-Use Domain Name
registry as part of the IANA Considerations section of this document
MUST be denied.
5.6. Domain Name Reservation Considerations for mail
5.6.1. Users
Are human users expected to recognize these names as special and use
them differently? In what way?
The reservations provided in this document are intended to reduce
spurious queries at the root of the DNS and avoid potential
collisions between resolutions of names in private name spaces and
the public DNS. Users do not have to know that these names are
special.
5.6.2. Application Software
Are writers of application software expected to make their software
recognize these names as special and treat them differently? In what
way? (For example, if a human user enters such a name, should the
application software reject it with an error message?)
These names are being added to the Special-Use Domain Name registry,
in part, because some application software implementations have long
used these names for special purposes in private networks.
Developers of new applications do not need to filter or test for the
names. Instead, the intent is to reserve the names for local use and
avoid unnecessary queries in the public DNS.
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5.6.3. Name Resolution APSs and Libraries
Are writers of name resolution APIs and libraries expected to make
their software recognize these names as special and treat them
differently? If so, how?
Authors of name resolution APIs and libraries SHOULD restrict these
names to local resolution and SHOULD NOT allow queries for strings
that use these Special-Use Domain Names to be forwarded to the public
DNS for resolution.
5.6.4. Caching DNS Servers
Are developers of caching domain name servers expected to make their
implementations recognize these names as special and treat them
differently? If so, how?
Authors of caching domain name server software SHOULD restrict these
names to local resolution and SHOULD NOT allow queries for strings
that use these Special-Use Domain Names to be forwarded to the public
DNS for resolution.
5.6.5. Authoritative DNS Servers
Are developers of authoritative domain name servers expected to make
their implementations recognize these names as special and treat them
differently? If so, how?
Authors of authoritative domain name server software SHOULD restrict
these names to local resolution and SHOULD NOT allow queries for
strings that use these Special-Use Domain Names to be forwarded to
the public DNS for resolution.
5.6.6. DNS Server Operators
Does this reserved Special-Use Domain Name have any potential impact
on DNS server operators? If they try to configure their
authoritative DNS server as authoritative for this reserved name,
will compliant name server software reject it as invalid? Do DNS
server operators need to know about that and understand why? Even if
the name server software doesn't prevent them from using this
reserved name, are there other ways that it may not work as expected,
of which the DNS server operator should be aware?
The intent of the reservations in this IANA Considerations section is
to prevent spurious and potentially problematic queries from
appearing in the public DNS. DNS server operators SHOULD always
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treat strings with the Special-Use Domain Names in section 5 as names
for local resolution.
Since these strings are intended to have local use, it is quite
possible that DNS operators would configure an authoritative DNS
server as authoritative for these reserved names in a private
network. This would be consistent with the goal of having these
names resolved locally rather than on the public Internet. Compliant
name server software MUST NOT reject these names as invalid.
Instead, name server software SHOULD allow for local resolution of
the name and SHOULD not transmit a query for resolution into the
public DNS.
5.6.7. DNS Registries/Registrars
How should DNS Registries/Registrars treat requests to register this
reserved domain name? Should such requests be denied? Should such
requests be allowed, but only to a specially-designated entity? (For
example, the name "www.example.org" is reserved for documentation
examples and is not available for registration; however, the name is
in fact registered; and there is even a web site at that name, which
states circularly that the name is reserved for use in documentation
and cannot be registered!)
Requests to register any names added to the Special-Use Domain Name
registry as part of the IANA Considerations section of this document
MUST be denied.
6. References
7. Acknowledgments
8. References
8.1. Normative References
[RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, November 1987.
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.
[RFC1591] Postel, J., "Domain Name System Structure and Delegation",
RFC 1591, March 1994.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
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[RFC2606] Eastlake, D. and A. Panitz, "Reserved Top Level DNS
Names", BCP 32, RFC 2606, June 1999.
[RFC6761] Cheshire, S. and M. Krochmal, "Special-Use Domain Names",
RFC 6761, February 2013.
8.2. Informative References
[ICANN_MITIGATION]
Internet Corporation for Assigned Names and Numbers,
"Guide to Name Collision Identification and Mitigation for
IT Professionals", August 2013, <http://www.icann.org/en/
about/staff/security/ssr/
name-collision-mitigation-05dec13-en.pdf>.
[INTERISLE]
Chapin, L., "Name Collision in the DNS", August 2013,
<http://www.icann.org/en/about/staff/security/ssr/
name-collision-02aug13-en.pdf>.
[JAS_MITIGATION]
Internet Corporation for Assigned Names and Numbers,
"Mitigating the Risk of DNS Namespace Collisions",
February 2014, <https://www.icann.org/en/about/staff/
security/ssr/name-collision-mitigation-26feb14-en.pdf>.
[]
claffy, kc., "DNS Research Update from CAIDA Status and
Recent Experiences", March 2009, <http://www.caida.org/
publications/presentations/2009/rssac_dns/rssac_dns.pdf>.
[SAC045] ICANN Security and Stability Advisory Committee, "Invalid
Top Level Domain Queries at the Root Level of the Domain
Name System", December 2010,
<http://www.icann.org/en/committees/security/sac045.pdf>.
[SAC062] ICANN Security and Stability Advisory Committee, "SSAC
Advisory Concerning the Mitigation of Name Collision
Risk", November 2013, <http://www.icann.org/en/groups/ssac
/documents/sac-062-en.pdf>.
Authors' Addresses
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Lyman Chapin (editor)
Interisle Consulting Group
125A Magazine Street
Cambridge, MA 02139
UK
Phone: +1 617 686 2527
Email: lyman@interisle.net
Mark McFadden (editor)
InterConnect Communications Ltd
Merlin House; Station Road
Chepstow, Monmouthshire NP16 5PB
UK
Phone: +44 7792 276 904
Email: markmcfadden@icc-uk.com
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