Internet DRAFT - draft-fujiwara-dnsop-unrelated-name-server
draft-fujiwara-dnsop-unrelated-name-server
Network Working Group K. Fujiwara
Internet-Draft JPRS
Intended status: Best Current Practice 1 March 2024
Expires: 2 September 2024
Unrelated name server name requirement
draft-fujiwara-dnsop-unrelated-name-server-00
Abstract
Unrelated(out-of-bailiwick) name server names are required for DNS
hosting services. However, using unrelated name server names
increases the name resolution costs. This document proposes using
in-domain name servers as much as possible for name resolution of
unrelated name server names to reduce the name resolution costs.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3
4. Recommendations for unrelated name server names . . . . . . . 3
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
6. Security Considerations . . . . . . . . . . . . . . . . . . . 3
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 3
7.1. Normative References . . . . . . . . . . . . . . . . . . 3
7.2. Informative References . . . . . . . . . . . . . . . . . 4
Appendix A. Examples of complex unrelated delegations . . . . . 4
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
[RFC9471] states that all in-domain glue records are attached to the
delegation response. Therefore, using in-domain name server names
for DNS delegation minimizes name resolution costs.
Unrelated (or, rarely sibling) name server names are used/required
for DNS hosting services.
However, using unrelated name server names increases the name
resolution costs and may increase the likelihood of name resolution
errors.
This document proposes to use in-domain name servers as much as
possible for name resolution of unrelated name server names in order
to reduce the name resolution costs.
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 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
Many of the specialized terms used in this document are defined in
DNS Terminology [RFC8499].
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3. Problem Statement
Unrelated(out-of-bailiwick) name server names are required for DNS
hosting services. However, using unrelated name server names
increases the name resolution costs. For some domain names, there
are multiple layers of dependence on unrelated name server names when
resolving the name.
Furthermore, there are cases where cyclic dependencies in delegation
occur, settings that depend on sibling glue, and cases where the
sibling glue disappears or some name servers stop responding, making
it impossible to resolve names.
[Tsuname2021] pointed out attacks and countermeasures that use
increased load due to cyclic dependencies.
Many cyclic delegations are likely due to misconfigurations.
To avoid complex name resolution and misconfigurations, the
recommendation to prevent unrelated name server names whenever
possible is needed.
4. Recommendations for unrelated name server names
Although it is acceptable to use unrelated name server names for DNS
delegation, the domain names that host the name server names MUST be
resolvable by delegations using one or more in-domain name server
names.
It is desirable for DNS hosting services that use unrelated name
server names in their services to be able to resolve their name
server names using only in-domain name server names.
5. IANA Considerations
This document requests no IANA actions.
6. Security Considerations
7. References
7.1. Normative References
[RFC2119] 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/rfc/rfc2119>.
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[RFC8174] 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/rfc/rfc8174>.
[RFC8499] Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS
Terminology", BCP 219, RFC 8499, DOI 10.17487/RFC8499,
January 2019, <https://www.rfc-editor.org/rfc/rfc8499>.
[RFC9471] Andrews, M., Huque, S., Wouters, P., and D. Wessels, "DNS
Glue Requirements in Referral Responses", RFC 9471,
DOI 10.17487/RFC9471, September 2023,
<https://www.rfc-editor.org/rfc/rfc9471>.
7.2. Informative References
[Tsuname2021]
Moura, G. M., Sebastian Castro, John S Heidemann, and Wes
Hardaker, "TsuNAME: exploiting misconfiguration and
vulnerability to DDoS DNS", IMC '21: Proceedings of the
21st ACM Internet Measurement Conference , 2021.
Appendix A. Examples of complex unrelated delegations
"com" TLD depends on "[a-m].gtld-servers.net" (sibling name server
names)
"gtld-servers.net" depends on "av[1-4].nsdlt.com.". (unrelated name
server names)
Finally, "nstld.com" depends on "av[1-4].nstld.com.". (in-domain)
Author's Address
Kazunori Fujiwara
Japan Registry Services Co., Ltd.
Email: fujiwara@jprs.co.jp
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