RFC 1591

Network Working Group                   		J. Postel
Request for Comments: 1591              		ISI
Category: Informational                 		March 1994


              Domain Name System Structure and Delegation


Status of this Memo

   This memo provides information for the Internet community.  
   This memo does not specify an Internet standard of any kind. 
   Distribution of this memo is unlimited.

1. Introduction

   This memo provides some information on the structure of
   the names in the Domain Name System (DNS), specifically
   the top-level domain names; and on the administration of
   domains. The Internet Assigned Numbers Authority (IANA)
   is the overall authority for the IP Addresses, the 
   Domain Names, and many other parameters, used in the 
   Internet.  The day-to-day responsibility for the assignment
   of IP Addresses, Autonomous System Numbers, and most top
   and second level Domain Names are handled by the Internet 
   Registry (IR) and regional registries.

2.  The Top Level Structure of the Domain Names

   In the Domain Name System (DNS) naming of computers there
   is a hierarchy of names.  The root of system is unnamed.
   There are a set of what are called "top-level domain
   names" (TLDs). These are the generic TLDs (EDU, COM, 
   NET, ORG, GOV, MIL, and INT), and the two letter country 
   codes from ISO-3166. It is extremely unlikely that any 
   other TLDs will be created.

   Under each TLD may be created a hierarchy of names.  
   Generally, under the generic TLDs the structure is very
   flat.  That is, many organizations are registered 
   directly under the TLD, and any further structure is up
   to the individual organizations.

   In the country TLDs, there is a wide variation in the 
   structure, in some countries the structure is very flat,
   in others there is substantial structural organization.
   In some country domains the second levels are generic 
   categories (such as, AC, CO, GO, and RE), in others they
   are based on political geography, and in still others,
   organization names are listed directly under the country
   code. The organization for the US country domain is 
   described in RFC 1480 [1].

   Each of the generic TLDs was created for a general 
   category of organizations.  The country code domains
   (for example, FR, NL, KR, US) are each organized by 
   an administrator for that country.  These administrators 
   may further delegate the management of portions of the
   naming tree.  These administrators are performing a 
   public service on behalf of the Internet community.
   Descriptions of the generic domains and the US country
   domain follow.

   Of these generic domains, five are international in 
   nature, and two are restricted to use by entities in
   the United States.

   World Wide Generic Domains:

   COM - This domain is intended for commercial entities, 
   		  that is companies.  This domain has grown very 
   		  large and there is concern about the administrative
   		  load and system performance if the current growth
   		  pattern is continued.  Consideration is being taken
   		  to subdivide the COM domain and only allow future
         commercial registrations in the subdomains.

   EDU - This domain was originally intended for all 
         educational institutions. Many Universities, 
         colleges, schools, educational service organizations,
         and educational consortia have registered here. More
         recently a decision has been taken to limit further 
         registrations to 4 year colleges and universities. 
         Schools and 2-year colleges will be registered in 
         the country domains (see US Domain, especially K12 
         and CC, below).

   NET - This domain is intended to hold only the computers 
         of network providers, that is the NIC and NOC 
         computers, the administrative computers, and the
         network node computers.  The customers of the 
         network provider would have domain names of
         their own (not in the NET TLD).

   ORG - This domain is intended as the miscellaneous TLD 
         for organizations that didn't fit anywhere else.
         Some non-government organizations may fit here.

   INT - This domain is for organizations established by 
         international treaties, or international 
         databases.

   United States Only Generic Domains:

   GOV - This domain was originally intended for any kind
         of government office or agency. More recently a 
         decision was taken to register only agencies of 
         the US Federal government in this domain. 
         State and local agencies are registered 
         in the country

         domains (see US Domain, below).

   MIL - This domain is used by the US military.

   Example country code Domain:

   US - As an example of a country domain, the US domain
        provides for the registration of all kinds of 
        entities in the United States on the basis of 
        political geography, that is, a hierarchy of
        
.
.
.US.  For example,
        "IBM.Armonk.NY.US".  In addition, 
        branches of the US domain are provided within 
        each state for schools (K12), community colleges
        (CC), technical schools (TEC), state government
        agencies (STATE), councils of governments (COG),
        libraries (LIB), museums (MUS), and several 
        other generic types of entities (see RFC 1480
        for details [1]).

   To find a contact for a TLD use the "whois" 
   program to access the database on the host 
   rs.internic.net.  Append "-dom" to the 
   name of TLD you are interested in.  For example:

                       whois -h rs.internic.net us-dom
      or
                       whois -h rs.internic.net edu-dom

3.  The Administration of Delegated Domains

   The Internet Assigned Numbers Authority (IANA) is 
   responsible for the overall coordination and 
   management of the Domain Name System (DNS), and 
   especially the delegation of portions of the name
   space called top-level domains.  Most of these
   top-level domains are two-letter country codes
   taken from the ISO standard 3166.

   A central Internet Registry (IR) has been selected
   and designated to handled the bulk of the 
   day-to-day administration of the Domain Name System. 
   Applications for new top-level domains (for example,
   country code domains) are handled by the IR with 
   consultation with the IANA. The central IR is 
   INTERNIC.NET.  Second level domains in COM, EDU,
   ORG, NET, and GOV are registered by the Internet 
   Registry at the InterNIC.  The second level domains
   in the MIL are registered by the DDN registry at 
   NIC.DDN.MIL.  Second level names in INT are
   registered by the PVM at ISI.EDU.

   While all requests for new top-level domains must
   be sent to the Internic (at hostmaster@internic.net),
   the regional registries are often enlisted to assist
   in the administration of the DNS, especially in 
   solving problems with a country administration. 
   Currently, the RIPE NCC is the regional registry
   for Europe and the APNIC is the regional registry
   for the Asia-Pacific region, while the INTERNIC
   administers the North America region, and all 
   the as yet undelegated regions.

      The contact mailboxes for these regional
      registries are:

         INTERNIC        hostmaster@internic.net
         APNIC           hostmaster@apnic.net
         RIPE NCC        ncc@ripe.net

   The policy concerns involved when a new top-level
   domain is established are described in the 
   following.  Also mentioned are concerns raised
   when it is necessary to change the delegation of an
   established domain from one party to another.

   A new top-level domain is usually created and 
   its management delegated to a "designated 
   manager" all at once.

   Most of these same concerns are relevant when 
   a sub-domain is delegated and in general the 
   principles described here apply recursively 
   to all delegations of the Internet DNS name
   space.

   The major concern in selecting a designated 
   manager for a domain is that it be able to 
   carry out the necessary responsibilities, 
   and have the ability to do a equitable, 
   just, honest, and competent job.

   1) The key requirement is that for each domain 
      there be a designated manager for supervising 
      that domain's name space.  In the case of
      top-level domains that are country codes this
      means that there is a manager that supervises
      the domain names and operates the domain
      name system in that country.

      The manager must, of course, be on the 
      Internet.  There must be Internet Protocol
      (IP) connectivity to the nameservers and email
      connectivity to the management and staff 
      of the manager.

      There must be an administrative contact and
      a technical contact for each domain. For 
      top-level domains that are country codes at
      least the administrative contact must reside
      in the country involved.

   2) These designated authorities are trustees 
      for the delegated domain, and have a duty 
      to serve the community.

      The designated manager is the trustee of 
      the top-level domain for both the nation, 
      in the case of a country code, and the 
      global Internet community.

      Concerns about "rights" and 
      "ownership" of domains are
      inappropriate.  It is appropriate to be 
      concerned about "responsibilities"
      and "service" to the community.

   3) The designated manager must be equitable to
      all groups in the domain that request 
      domain names.

      This means that the same rules are applied
      to all requests, all requests must be 
      processed in a non-discriminatory fashion,
      and academic and commercial (and other)
      users are treated on an equal basis. 
      No bias shall be shown regarding requests
      that may come from customers of some other
      business related to the manager --
      e.g., no preferential service for 
      customers of a particular data network 
      provider. There can be no requirement that
      a particular mail system (or other 
      application), protocol, or product be used.

      There are no requirements on subdomains of
      top-level domains beyond the requirements
      on higher-level domains themselves.  That
      is, the requirements in this memo are 
      applied recursively. In particular, all 
      subdomains shall be allowed to operate 
      their own domain name servers, providing
      in them whatever information the subdomain
      manager sees fit (as long as it is true
      and correct).

   4) Significantly interested parties in the 
      domain should agree that the designated 
      manager is the appropriate party.

      The IANA tries to have any contending 
      parties reach agreement among themselves,
      and generally takes no action to change
      things unless all the contending parties
      agree; only in cases where the designated 
      manager has substantially mis-behaved 
      would the IANA step in.

      However, it is also appropriate for 
      interested parties to have some voice 
      in selecting the designated manager.

      There are two cases where the IANA and 
      the central IR may establish a new 
      top-level domain and delegate only a 
      portion of it: (1) there are contending
      parties that cannot agree, or (2) the
      applying party may not be able to 
      represent or serve the whole country. 
      The later case sometimes arises when a 
      party outside a country is trying to be 
      helpful in getting networking started in a
      country -- this is sometimes called a 
      "proxy" DNS service.

      The Internet DNS Names Review Board (IDNB), 
      a committee established by the IANA, will
      act as a review panel for cases in which 
      the parties can not reach agreement among 
      themselves. The IDNB's decisions will be 
      binding.

   5) The designated manager must do a satisfactory
      job of operating the DNS service for the domain.

      That is, the actual management of the assigning
      of domain names, delegating subdomains and 
      operating nameservers must be done with 
      technical competence.  This includes keeping 
      the central IR (in the case of top-level 
      domains) or other higher-level domain manager
      advised of the status of the domain, responding
      to requests in a timely manner, and operating 
      the database with accuracy, robustness, and 
      resilience.

      There must be a primary and a secondary 
      nameserver that have IP connectivity to the 
      Internet and can be easily checked for 
      operational status and database accuracy by
      the IR and the IANA.

      In cases when there are persistent problems
      with the proper operation of a domain, the 
      delegation may be revoked, and possibly
      delegated to another designated manager.

   6) For any transfer of the designated manager 
      trusteeship from one organization to another, 
      the higher-level domain manager (the IANA in 
      the case of top-level domains) must receive 
      communications from both the old organization 
      and the new organization that assure the IANA
      that the transfer in mutually agreed, and that
      the new organization understands its 
      responsibilities.

      It is also very helpful for the IANA to 
      receive communications from other parties 
      that may be concerned or affected by the
      transfer.

4. Rights to Names

   1) Names and Trademarks

      In case of a dispute between domain name 
      registrants as to the rights to a particular 
      name, the registration authority shall have 
      no role or responsibility other than to 
      provide the contact information to both 
      parties.

      The registration of a domain name does not
      have any Trademark status.  It is up to the
      requestor to be sure he is not violating
      anyone else's Trademark.

   2) Country Codes

      The IANA is not in the business of deciding 
      what is and what is not a country.

      The selection of the ISO 3166 list as a 
      basis for country code top-level domain 
      names was made with the knowledge that 
      ISO has a procedure for determining which 
      entities should be and should not be on 
      that list.

5. Security Considerations

   Security issues are not discussed in this memo.

6. Acknowledgements

   Many people have made comments on draft version
   of these descriptions and procedures. Steve 
   Goldstein and John Klensin have been
   particularly helpful.

7. Author's Address

   Jon Postel
   USC/Information Sciences Institute
   4676 Admiralty Way
   Marina del Rey, CA  90292

   Phone: 310-822-1511
   Fax:   310-823-6714
   EMail: Postel@ISI.EDU

7. References

   [1] Cooper, A., and J. Postel, "The US 
       Domain", RFC 1480,
       USC/Information Sciences Institute, June 1993.

   [2] Reynolds, J., and J. Postel, "Assigned 
       Numbers", STD 2, RFC 1340,
       USC/Information Sciences Institute, July 1992.

   [3] Mockapetris, P., "Domain Names - Concepts 
       and Facilities", STD
       13, RFC 1034, USC/Information Sciences Institute, 
       November 1987.

   [4] Mockapetris, P., "Domain Names - 
       Implementation and
       Specification", STD 13, RFC 1035, 
       USC/Information Sciences
       Institute, November 1987.

   [6] Partridge, C., "Mail Routing and the 
       Domain System", STD 14, RFC
       974, CSNET CIC BBN, January 1986.

   [7] Braden, R., Editor, "Requirements 
       for Internet Hosts --
       Application and Support", STD 3, 
       RFC 1123, Internet Engineering
       Task Force, October 1989.