Internet Engineering Task Force (IETF)                       M. Blanchet
Request for Comments: 7720                                      Viagenie
BCP: 40                                                       L-J. Liman
Obsoletes: 2870                                                   Netnod
Category: Best Current Practice                            December 2015
ISSN: 2070-1721


       DNS Root Name Service Protocol and Deployment Requirements

Abstract

   The DNS root name service is a critical part of the Internet
   architecture.  The protocol and deployment requirements for the DNS
   root name service are defined in this document.  Operational
   requirements are out of scope.

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 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7720.

Copyright Notice

   Copyright (c) 2015 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
   (http://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.  Relationship to RFC 2870  . . . . . . . . . . . . . . . .   2
   2.  Protocol Requirements . . . . . . . . . . . . . . . . . . . .   3
   3.  Deployment Requirements . . . . . . . . . . . . . . . . . . .   3
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   5.  Informative References  . . . . . . . . . . . . . . . . . . .   4
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   [RFC2870] discusses protocol and operational requirements for root
   name servers for the Internet's domain name system (DNS) protocol
   [RFC1035].  Since its publication, both protocol and operational
   requirements have evolved.  It makes more sense now to separate the
   two sets of requirements into two separate documents.  This document
   only defines the protocol requirements and some deployment
   requirements.  The operational requirements that were defined in RFC
   2870 have been removed.  Operational requirements are now defined by
   the Root Server System Advisory Committee of ICANN and are documented
   in [RSSAC-001].

   The root servers are authoritative servers of the unique [RFC2826]
   root zone (".") [ROOTZONE].  They currently also serve the root-
   servers.net zone.  Some also serve the zone for the .arpa top-level
   domain [ARPAZONE] [RFC3172].  This document describes the external
   interface of the root name servers from a protocol viewpoint of the
   service.  It specifies basic requirements for the Internet that DNS
   clients meet when interacting with a root name service over the
   public Internet.

   The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
   SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this
   document, are to be interpreted as described in BCP 14, [RFC2119].

1.1.  Relationship to RFC 2870

   This document obsoletes [RFC2870].

   This document and [RSSAC-001] together functionally replace
   [RFC2870].

2.  Protocol Requirements

   This section describes the minimum high-level protocol requirements.
   Operative details are documented in [RSSAC-001].

   The root name service:

   o  MUST implement core DNS [RFC1035] and clarifications to the DNS
      [RFC2181].

   o  MUST support IPv4 [RFC791] and IPv6 [RFC2460] transport of DNS
      queries and responses.

   o  MUST support UDP [RFC768] and TCP [RFC793] transport of DNS
      queries and responses.

   o  MUST generate checksums when sending UDP datagrams and MUST verify
      checksums when receiving UDP datagrams containing a non-zero
      checksum.

   o  MUST implement DNSSEC [RFC4035] as an authoritative name service.

   o  MUST implement extension mechanisms for DNS (EDNS(0)) [RFC6891].

3.  Deployment Requirements

   The root name service:

   o  MUST answer queries from any entity conforming to [RFC1122] with a
      valid IP address.

   o  MUST serve the unique [RFC2826] root zone [ROOTZONE].

4.  Security Considerations

   This document does not specify a new protocol.  However, the root
   name service is a key component of the Internet architecture and play
   a key role into the overall security of the Internet [RFC2826].
   Specific security considerations on the DNS protocols are discussed
   in their respective specifications.  The security considerations on
   the operational side of the root name servers are discussed in
   [RSSAC-001].

5.  Informative References

   [ARPAZONE]  IANA, ".ARPA Zone Management",
               <http://www.iana.org/domains/arpa>.

   [RFC768]    Postel, J., "User Datagram Protocol", STD 6, RFC 768,
               DOI 10.17487/RFC0768, August 1980,
               <http://www.rfc-editor.org/info/rfc768>.

   [RFC791]    Postel, J., "Internet Protocol", STD 5, RFC 791,
               DOI 10.17487/RFC0791, September 1981,
               <http://www.rfc-editor.org/info/rfc791>.

   [RFC793]    Postel, J., "Transmission Control Protocol", STD 7,
               RFC 793, DOI 10.17487/RFC0793, September 1981,
               <http://www.rfc-editor.org/info/rfc793>.

   [RFC1035]   Mockapetris, P., "Domain names - implementation and
               specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
               November 1987, <http://www.rfc-editor.org/info/rfc1035>.

   [RFC1122]   Braden, R., Ed., "Requirements for Internet Hosts -
               Communication Layers", STD 3, RFC 1122,
               DOI 10.17487/RFC1122, October 1989,
               <http://www.rfc-editor.org/info/rfc1122>.

   [RFC2119]   Bradner, S., "Key words for use in RFCs to Indicate
               Requirement Levels", BCP 14, RFC 2119,
               DOI 10.17487/RFC2119, March 1997,
               <http://www.rfc-editor.org/info/rfc2119>.

   [RFC2181]   Elz, R. and R. Bush, "Clarifications to the DNS
               Specification", RFC 2181, DOI 10.17487/RFC2181, July
               1997, <http://www.rfc-editor.org/info/rfc2181>.

   [RFC2460]   Deering, S. and R. Hinden, "Internet Protocol, Version 6
               (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460,
               December 1998, <http://www.rfc-editor.org/info/rfc2460>.

   [RFC2826]   Internet Architecture Board, "IAB Technical Comment on
               the Unique DNS Root", RFC 2826, DOI 10.17487/RFC2826, May
               2000, <http://www.rfc-editor.org/info/rfc2826>.

   [RFC2870]   Bush, R., Karrenberg, D., Kosters, M., and R. Plzak,
               "Root Name Server Operational Requirements", BCP 40,
               RFC 2870, DOI 10.17487/RFC2870, June 2000,
               <http://www.rfc-editor.org/info/rfc2870>.

   [RFC3172]   Huston, G., Ed., "Management Guidelines & Operational
               Requirements for the Address and Routing Parameter Area
               Domain ("arpa")", BCP 52, RFC 3172, DOI 10.17487/RFC3172,
               September 2001, <http://www.rfc-editor.org/info/rfc3172>.

   [RFC4035]   Arends, R., Austein, R., Larson, M., Massey, D., and S.
               Rose, "Protocol Modifications for the DNS Security
               Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005,
               <http://www.rfc-editor.org/info/rfc4035>.

   [RFC6891]   Damas, J., Graff, M., and P. Vixie, "Extension Mechanisms
               for DNS (EDNS(0))", STD 75, RFC 6891,
               DOI 10.17487/RFC6891, April 2013,
               <http://www.rfc-editor.org/info/rfc6891>.

   [ROOTZONE]  "Root Zone", <ftp://rs.internic.net/domain/root.zone>.

   [RSSAC-001] Root Server System Advisory Committee (RSSAC), "Service
               Expectations of Root Servers", November 2014,
               <https://www.icann.org/en/system/files/files/
               rssac-001-root-service-expectations-04dec15-en.pdf>.

Acknowledgements

   Some text was taken from [RFC2870].  The editors of this document
   would like to sincerely thank the following individuals for valuable
   contributions to the text: Andrew Sullivan, Simon Perreault,
   Jean-Philippe Dionne, Dave Thaler, Russ Housley, Alissa Cooper, Joe
   Abley, Joao Damas, Daniel Karrenberg, Jacques Latour, Eliot Lear,
   Bill Manning, David Conrad, Paul Hoffman, Terry Manderson, Jari
   Arkko, and Mark Andrews.

Authors' Addresses

   Marc Blanchet
   Viagenie
   246 Aberdeen
   Quebec, QC  G1R 2E1
   Canada

   Email: Marc.Blanchet@viagenie.ca
   URI:   http://viagenie.ca


   Lars-Johan Liman
   Netnod Internet Exchange
   Box 30194
   SE-104 25 Stockholm
   Sweden

   Email: liman@netnod.se
   URI:   http://www.netnod.se/