1 Internet Engineering Task Force (IETF)                       M. Blanchet   
    2 Request for Comments: 7720                                      Viagenie   
    3 BCP: 40                                                       L-J. Liman   
    4 Obsoletes: 2870                                                   Netnod   
    5 Category: Best Current Practice                            December 2015   
    6 ISSN: 2070-1721                                                            
    7                                                                            
    8                                                                            
    9        DNS Root Name Service Protocol and Deployment Requirements          
   10                                                                            
   11 Abstract                                                                   
   12                                                                            
   13    The DNS root name service is a critical part of the Internet            
   14    architecture.  The protocol and deployment requirements for the DNS     
   15    root name service are defined in this document.  Operational            
   16    requirements are out of scope.                                          
   17                                                                            
   18 Status of This Memo                                                        
   19                                                                            
   20    This memo documents an Internet Best Current Practice.                  
   21                                                                            
   22    This document is a product of the Internet Engineering Task Force       
   23    (IETF).  It represents the consensus of the IETF community.  It has     
   24    received public review and has been approved for publication by the     
   25    Internet Engineering Steering Group (IESG).  Further information on     
   26    BCPs is available in Section 2 of RFC 5741.                             
   27                                                                            
   28    Information about the current status of this document, any errata,      
   29    and how to provide feedback on it may be obtained at                    
   30    http://www.rfc-editor.org/info/rfc7720.                                 
   31                                                                            
   32 Copyright Notice                                                           
   33                                                                            
   34    Copyright (c) 2015 IETF Trust and the persons identified as the         
   35    document authors.  All rights reserved.                                 
   36                                                                            
   37    This document is subject to BCP 78 and the IETF Trust's Legal           
   38    Provisions Relating to IETF Documents                                   
   39    (http://trustee.ietf.org/license-info) in effect on the date of         
   40    publication of this document.  Please review these documents            
   41    carefully, as they describe your rights and restrictions with respect   
   42    to this document.  Code Components extracted from this document must    
   43    include Simplified BSD License text as described in Section 4.e of      
   44    the Trust Legal Provisions and are provided without warranty as         
   45    described in the Simplified BSD License.                                
   46                                                                            
   47                                                                            
   48                                                                            
   49                                                                            
   50                                                                            
   51                                                                            
   52 Blanchet & Liman          Best Current Practice                 [Page 1]   

   53 RFC 7720             Root Name Service Requirements        December 2015   
   54                                                                            
   55                                                                            
   56 Table of Contents                                                          
   57                                                                            
   58    1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2   
   59      1.1.  Relationship to RFC 2870  . . . . . . . . . . . . . . . .   2   
   60    2.  Protocol Requirements . . . . . . . . . . . . . . . . . . . .   3   
   61    3.  Deployment Requirements . . . . . . . . . . . . . . . . . . .   3   
   62    4.  Security Considerations . . . . . . . . . . . . . . . . . . .   3   
   63    5.  Informative References  . . . . . . . . . . . . . . . . . . .   4   
   64    Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   5   
   65    Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6   
   66                                                                            
   67 1.  Introduction                                                           
   68                                                                            
   69    [RFC2870] discusses protocol and operational requirements for root      
   70    name servers for the Internet's domain name system (DNS) protocol       
   71    [RFC1035].  Since its publication, both protocol and operational        
   72    requirements have evolved.  It makes more sense now to separate the     
   73    two sets of requirements into two separate documents.  This document    
   74    only defines the protocol requirements and some deployment              
   75    requirements.  The operational requirements that were defined in RFC    
   76    2870 have been removed.  Operational requirements are now defined by    
   77    the Root Server System Advisory Committee of ICANN and are documented   
   78    in [RSSAC-001].                                                         
   79                                                                            
   80    The root servers are authoritative servers of the unique [RFC2826]      
   81    root zone (".") [ROOTZONE].  They currently also serve the root-        
   82    servers.net zone.  Some also serve the zone for the .arpa top-level     
   83    domain [ARPAZONE] [RFC3172].  This document describes the external      
   84    interface of the root name servers from a protocol viewpoint of the     
   85    service.  It specifies basic requirements for the Internet that DNS     
   86    clients meet when interacting with a root name service over the         
   87    public Internet.                                                        
   88                                                                            
   89    The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,        
   90    SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this    
   91    document, are to be interpreted as described in BCP 14, [RFC2119].      
   92                                                                            
   93 1.1.  Relationship to RFC 2870                                             
   94                                                                            
   95    This document obsoletes [RFC2870].                                      
   96                                                                            
   97    This document and [RSSAC-001] together functionally replace             
   98    [RFC2870].                                                              
   99                                                                            
  100                                                                            
  101                                                                            
  102                                                                            
  103                                                                            
  104                                                                            
  105                                                                            
  106                                                                            
  107 Blanchet & Liman          Best Current Practice                 [Page 2]   

  108 RFC 7720             Root Name Service Requirements        December 2015   
  109                                                                            
  110                                                                            
  111 2.  Protocol Requirements                                                  
  112                                                                            
  113    This section describes the minimum high-level protocol requirements.    
  114    Operative details are documented in [RSSAC-001].                        
  115                                                                            
  116    The root name service:                                                  
  117                                                                            
  118    o  MUST implement core DNS [RFC1035] and clarifications to the DNS      
  119       [RFC2181].                                                           
  120                                                                            
  121    o  MUST support IPv4 [RFC791] and IPv6 [RFC2460] transport of DNS       
  122       queries and responses.                                               
  123                                                                            
  124    o  MUST support UDP [RFC768] and TCP [RFC793] transport of DNS          
  125       queries and responses.                                               
  126                                                                            
  127    o  MUST generate checksums when sending UDP datagrams and MUST verify   
  128       checksums when receiving UDP datagrams containing a non-zero         
  129       checksum.                                                            
  130                                                                            
  131    o  MUST implement DNSSEC [RFC4035] as an authoritative name service.    
  132                                                                            
  133    o  MUST implement extension mechanisms for DNS (EDNS(0)) [RFC6891].     
  134                                                                            
  135 3.  Deployment Requirements                                                
  136                                                                            
  137    The root name service:                                                  
  138                                                                            
  139    o  MUST answer queries from any entity conforming to [RFC1122] with a   
  140       valid IP address.                                                    
  141                                                                            
  142    o  MUST serve the unique [RFC2826] root zone [ROOTZONE].                
  143                                                                            
  144 4.  Security Considerations                                                
  145                                                                            
  146    This document does not specify a new protocol.  However, the root       
  147    name service is a key component of the Internet architecture and play   
  148    a key role into the overall security of the Internet [RFC2826].         
  149    Specific security considerations on the DNS protocols are discussed     
  150    in their respective specifications.  The security considerations on     
  151    the operational side of the root name servers are discussed in          
  152    [RSSAC-001].                                                            
  153                                                                            
  154                                                                            
  155                                                                            
  156                                                                            
  157                                                                            
  158                                                                            
  159                                                                            
  160                                                                            
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  162 Blanchet & Liman          Best Current Practice                 [Page 3]   

  163 RFC 7720             Root Name Service Requirements        December 2015   
  164                                                                            
  165                                                                            
  166 5.  Informative References                                                 
  167                                                                            
  168    [ARPAZONE]  IANA, ".ARPA Zone Management",                              
  169                <http://www.iana.org/domains/arpa>.                         
  170                                                                            
  171    [RFC768]    Postel, J., "User Datagram Protocol", STD 6, RFC 768,       
  172                DOI 10.17487/RFC0768, August 1980,                          
  173                <http://www.rfc-editor.org/info/rfc768>.                    
  174                                                                            
  175    [RFC791]    Postel, J., "Internet Protocol", STD 5, RFC 791,            
  176                DOI 10.17487/RFC0791, September 1981,                       
  177                <http://www.rfc-editor.org/info/rfc791>.                    
  178                                                                            
  179    [RFC793]    Postel, J., "Transmission Control Protocol", STD 7,         
  180                RFC 793, DOI 10.17487/RFC0793, September 1981,              
  181                <http://www.rfc-editor.org/info/rfc793>.                    
  182                                                                            
  183    [RFC1035]   Mockapetris, P., "Domain names - implementation and         
  184                specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,     
  185                November 1987, <http://www.rfc-editor.org/info/rfc1035>.    
  186                                                                            
  187    [RFC1122]   Braden, R., Ed., "Requirements for Internet Hosts -         
  188                Communication Layers", STD 3, RFC 1122,                     
  189                DOI 10.17487/RFC1122, October 1989,                         
  190                <http://www.rfc-editor.org/info/rfc1122>.                   
  191                                                                            
  192    [RFC2119]   Bradner, S., "Key words for use in RFCs to Indicate         
  193                Requirement Levels", BCP 14, RFC 2119,                      
  194                DOI 10.17487/RFC2119, March 1997,                           
  195                <http://www.rfc-editor.org/info/rfc2119>.                   
  196                                                                            
  197    [RFC2181]   Elz, R. and R. Bush, "Clarifications to the DNS             
  198                Specification", RFC 2181, DOI 10.17487/RFC2181, July        
  199                1997, <http://www.rfc-editor.org/info/rfc2181>.             
  200                                                                            
  201    [RFC2460]   Deering, S. and R. Hinden, "Internet Protocol, Version 6    
  202                (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460,      
  203                December 1998, <http://www.rfc-editor.org/info/rfc2460>.    
  204                                                                            
  205    [RFC2826]   Internet Architecture Board, "IAB Technical Comment on      
  206                the Unique DNS Root", RFC 2826, DOI 10.17487/RFC2826, May   
  207                2000, <http://www.rfc-editor.org/info/rfc2826>.             
  208                                                                            
  209    [RFC2870]   Bush, R., Karrenberg, D., Kosters, M., and R. Plzak,        
  210                "Root Name Server Operational Requirements", BCP 40,        
  211                RFC 2870, DOI 10.17487/RFC2870, June 2000,                  
  212                <http://www.rfc-editor.org/info/rfc2870>.                   
  213                                                                            
  214                                                                            
  215                                                                            
  216                                                                            
  217 Blanchet & Liman          Best Current Practice                 [Page 4]   

  218 RFC 7720             Root Name Service Requirements        December 2015   
  219                                                                            
  220                                                                            
  221    [RFC3172]   Huston, G., Ed., "Management Guidelines & Operational       
  222                Requirements for the Address and Routing Parameter Area     
  223                Domain ("arpa")", BCP 52, RFC 3172, DOI 10.17487/RFC3172,   
  224                September 2001, <http://www.rfc-editor.org/info/rfc3172>.   
  225                                                                            
  226    [RFC4035]   Arends, R., Austein, R., Larson, M., Massey, D., and S.     
  227                Rose, "Protocol Modifications for the DNS Security          
  228                Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005,    
  229                <http://www.rfc-editor.org/info/rfc4035>.                   
  230                                                                            
  231    [RFC6891]   Damas, J., Graff, M., and P. Vixie, "Extension Mechanisms   
  232                for DNS (EDNS(0))", STD 75, RFC 6891,                       
  233                DOI 10.17487/RFC6891, April 2013,                           
  234                <http://www.rfc-editor.org/info/rfc6891>.                   
  235                                                                            
  236    [ROOTZONE]  "Root Zone", <ftp://rs.internic.net/domain/root.zone>.      
  237                                                                            
  238    [RSSAC-001] Root Server System Advisory Committee (RSSAC), "Service     
  239                Expectations of Root Servers", November 2014,               
  240                <https://www.icann.org/en/system/files/files/               
  241                rssac-001-root-service-expectations-04dec15-en.pdf>.        
  242                                                                            
  243 Acknowledgements                                                           
  244                                                                            
  245    Some text was taken from [RFC2870].  The editors of this document       
  246    would like to sincerely thank the following individuals for valuable    
  247    contributions to the text: Andrew Sullivan, Simon Perreault,            
  248    Jean-Philippe Dionne, Dave Thaler, Russ Housley, Alissa Cooper, Joe     
  249    Abley, Joao Damas, Daniel Karrenberg, Jacques Latour, Eliot Lear,       
  250    Bill Manning, David Conrad, Paul Hoffman, Terry Manderson, Jari         
  251    Arkko, and Mark Andrews.                                                
  252                                                                            
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  272 Blanchet & Liman          Best Current Practice                 [Page 5]   

  273 RFC 7720             Root Name Service Requirements        December 2015   
  274                                                                            
  275                                                                            
  276 Authors' Addresses                                                         
  277                                                                            
  278    Marc Blanchet                                                           
  279    Viagenie                                                                
  280    246 Aberdeen                                                            
  281    Quebec, QC  G1R 2E1                                                     
  282    Canada                                                                  
  283                                                                            
  284    Email: Marc.Blanchet@viagenie.ca                                        
  285    URI:   http://viagenie.ca                                               
  286                                                                            
  287                                                                            
  288    Lars-Johan Liman                                                        
  289    Netnod Internet Exchange                                                
  290    Box 30194                                                               
  291    SE-104 25 Stockholm                                                     
  292    Sweden                                                                  
  293                                                                            
  294    Email: liman@netnod.se                                                  
  295    URI:   http://www.netnod.se/                                            
  296                                                                            
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  328                                                                            

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