396 lines
16 KiB
Plaintext
396 lines
16 KiB
Plaintext
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Network Working Group J. Postel
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Request for Comments: 1591 ISI
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Category: Informational March 1994
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Domain Name System Structure and Delegation
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Status of this Memo
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This memo provides information for the Internet community. This memo
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does not specify an Internet standard of any kind. Distribution of
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this memo is unlimited.
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1. Introduction
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This memo provides some information on the structure of the names in
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the Domain Name System (DNS), specifically the top-level domain
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names; and on the administration of domains. The Internet Assigned
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Numbers Authority (IANA) is the overall authority for the IP
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Addresses, the Domain Names, and many other parameters, used in the
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Internet. The day-to-day responsibility for the assignment of IP
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Addresses, Autonomous System Numbers, and most top and second level
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Domain Names are handled by the Internet Registry (IR) and regional
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registries.
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2. The Top Level Structure of the Domain Names
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In the Domain Name System (DNS) naming of computers there is a
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hierarchy of names. The root of system is unnamed. There are a set
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of what are called "top-level domain names" (TLDs). These are the
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generic TLDs (EDU, COM, NET, ORG, GOV, MIL, and INT), and the two
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letter country codes from ISO-3166. It is extremely unlikely that
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any other TLDs will be created.
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Under each TLD may be created a hierarchy of names. Generally, under
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the generic TLDs the structure is very flat. That is, many
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organizations are registered directly under the TLD, and any further
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structure is up to the individual organizations.
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In the country TLDs, there is a wide variation in the structure, in
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some countries the structure is very flat, in others there is
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substantial structural organization. In some country domains the
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second levels are generic categories (such as, AC, CO, GO, and RE),
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in others they are based on political geography, and in still others,
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organization names are listed directly under the country code. The
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organization for the US country domain is described in RFC 1480 [1].
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Postel [Page 1]
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RFC 1591 Domain Name System Structure and Delegation March 1994
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Each of the generic TLDs was created for a general category of
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organizations. The country code domains (for example, FR, NL, KR,
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US) are each organized by an administrator for that country. These
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administrators may further delegate the management of portions of the
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naming tree. These administrators are performing a public service on
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behalf of the Internet community. Descriptions of the generic
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domains and the US country domain follow.
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Of these generic domains, five are international in nature, and two
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are restricted to use by entities in the United States.
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World Wide Generic Domains:
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COM - This domain is intended for commercial entities, that is
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companies. This domain has grown very large and there is
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concern about the administrative load and system performance if
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the current growth pattern is continued. Consideration is
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being taken to subdivide the COM domain and only allow future
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commercial registrations in the subdomains.
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EDU - This domain was originally intended for all educational
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institutions. Many Universities, colleges, schools,
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educational service organizations, and educational consortia
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have registered here. More recently a decision has been taken
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to limit further registrations to 4 year colleges and
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universities. Schools and 2-year colleges will be registered
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in the country domains (see US Domain, especially K12 and CC,
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below).
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NET - This domain is intended to hold only the computers of network
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providers, that is the NIC and NOC computers, the
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administrative computers, and the network node computers. The
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customers of the network provider would have domain names of
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their own (not in the NET TLD).
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ORG - This domain is intended as the miscellaneous TLD for
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organizations that didn't fit anywhere else. Some non-
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government organizations may fit here.
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INT - This domain is for organizations established by international
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treaties, or international databases.
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United States Only Generic Domains:
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GOV - This domain was originally intended for any kind of government
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office or agency. More recently a decision was taken to
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register only agencies of the US Federal government in this
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domain. State and local agencies are registered in the country
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Postel [Page 2]
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RFC 1591 Domain Name System Structure and Delegation March 1994
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domains (see US Domain, below).
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MIL - This domain is used by the US military.
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Example country code Domain:
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US - As an example of a country domain, the US domain provides for
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the registration of all kinds of entities in the United States
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on the basis of political geography, that is, a hierarchy of
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<entity-name>.<locality>.<state-code>.US. For example,
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"IBM.Armonk.NY.US". In addition, branches of the US domain are
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provided within each state for schools (K12), community colleges
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(CC), technical schools (TEC), state government agencies
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(STATE), councils of governments (COG),libraries (LIB), museums
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(MUS), and several other generic types of entities (see RFC 1480
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for details [1]).
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To find a contact for a TLD use the "whois" program to access the
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database on the host rs.internic.net. Append "-dom" to the name of
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TLD you are interested in. For example:
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whois -h rs.internic.net us-dom
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or
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whois -h rs.internic.net edu-dom
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3. The Administration of Delegated Domains
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The Internet Assigned Numbers Authority (IANA) is responsible for the
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overall coordination and management of the Domain Name System (DNS),
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and especially the delegation of portions of the name space called
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top-level domains. Most of these top-level domains are two-letter
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country codes taken from the ISO standard 3166.
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A central Internet Registry (IR) has been selected and designated to
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handled the bulk of the day-to-day administration of the Domain Name
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System. Applications for new top-level domains (for example, country
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code domains) are handled by the IR with consultation with the IANA.
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The central IR is INTERNIC.NET. Second level domains in COM, EDU,
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ORG, NET, and GOV are registered by the Internet Registry at the
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InterNIC. The second level domains in the MIL are registered by the
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DDN registry at NIC.DDN.MIL. Second level names in INT are
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registered by the PVM at ISI.EDU.
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While all requests for new top-level domains must be sent to the
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Internic (at hostmaster@internic.net), the regional registries are
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often enlisted to assist in the administration of the DNS, especially
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in solving problems with a country administration. Currently, the
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RIPE NCC is the regional registry for Europe and the APNIC is the
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Postel [Page 3]
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RFC 1591 Domain Name System Structure and Delegation March 1994
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regional registry for the Asia-Pacific region, while the INTERNIC
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administers the North America region, and all the as yet undelegated
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regions.
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The contact mailboxes for these regional registries are:
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INTERNIC hostmaster@internic.net
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APNIC hostmaster@apnic.net
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RIPE NCC ncc@ripe.net
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The policy concerns involved when a new top-level domain is
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established are described in the following. Also mentioned are
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concerns raised when it is necessary to change the delegation of an
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established domain from one party to another.
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A new top-level domain is usually created and its management
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delegated to a "designated manager" all at once.
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Most of these same concerns are relevant when a sub-domain is
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delegated and in general the principles described here apply
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recursively to all delegations of the Internet DNS name space.
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The major concern in selecting a designated manager for a domain is
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that it be able to carry out the necessary responsibilities, and have
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the ability to do a equitable, just, honest, and competent job.
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1) The key requirement is that for each domain there be a designated
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manager for supervising that domain's name space. In the case of
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top-level domains that are country codes this means that there is
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a manager that supervises the domain names and operates the domain
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name system in that country.
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The manager must, of course, be on the Internet. There must be
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Internet Protocol (IP) connectivity to the nameservers and email
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connectivity to the management and staff of the manager.
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There must be an administrative contact and a technical contact
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for each domain. For top-level domains that are country codes at
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least the administrative contact must reside in the country
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involved.
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2) These designated authorities are trustees for the delegated
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domain, and have a duty to serve the community.
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The designated manager is the trustee of the top-level domain for
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both the nation, in the case of a country code, and the global
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Internet community.
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Postel [Page 4]
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RFC 1591 Domain Name System Structure and Delegation March 1994
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Concerns about "rights" and "ownership" of domains are
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inappropriate. It is appropriate to be concerned about
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"responsibilities" and "service" to the community.
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3) The designated manager must be equitable to all groups in the
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domain that request domain names.
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This means that the same rules are applied to all requests, all
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requests must be processed in a non-discriminatory fashion, and
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academic and commercial (and other) users are treated on an equal
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basis. No bias shall be shown regarding requests that may come
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from customers of some other business related to the manager --
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e.g., no preferential service for customers of a particular data
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network provider. There can be no requirement that a particular
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mail system (or other application), protocol, or product be used.
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There are no requirements on subdomains of top-level domains
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beyond the requirements on higher-level domains themselves. That
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is, the requirements in this memo are applied recursively. In
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particular, all subdomains shall be allowed to operate their own
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domain name servers, providing in them whatever information the
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subdomain manager sees fit (as long as it is true and correct).
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4) Significantly interested parties in the domain should agree that
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the designated manager is the appropriate party.
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The IANA tries to have any contending parties reach agreement
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among themselves, and generally takes no action to change things
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unless all the contending parties agree; only in cases where the
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designated manager has substantially mis-behaved would the IANA
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step in.
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However, it is also appropriate for interested parties to have
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some voice in selecting the designated manager.
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There are two cases where the IANA and the central IR may
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establish a new top-level domain and delegate only a portion of
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it: (1) there are contending parties that cannot agree, or (2) the
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applying party may not be able to represent or serve the whole
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country. The later case sometimes arises when a party outside a
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country is trying to be helpful in getting networking started in a
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country -- this is sometimes called a "proxy" DNS service.
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The Internet DNS Names Review Board (IDNB), a committee
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established by the IANA, will act as a review panel for cases in
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which the parties can not reach agreement among themselves. The
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IDNB's decisions will be binding.
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Postel [Page 5]
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RFC 1591 Domain Name System Structure and Delegation March 1994
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5) The designated manager must do a satisfactory job of operating the
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DNS service for the domain.
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That is, the actual management of the assigning of domain names,
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delegating subdomains and operating nameservers must be done with
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technical competence. This includes keeping the central IR (in
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the case of top-level domains) or other higher-level domain
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manager advised of the status of the domain, responding to
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requests in a timely manner, and operating the database with
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accuracy, robustness, and resilience.
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There must be a primary and a secondary nameserver that have IP
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connectivity to the Internet and can be easily checked for
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operational status and database accuracy by the IR and the IANA.
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In cases when there are persistent problems with the proper
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operation of a domain, the delegation may be revoked, and possibly
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delegated to another designated manager.
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6) For any transfer of the designated manager trusteeship from one
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organization to another, the higher-level domain manager (the IANA
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in the case of top-level domains) must receive communications from
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both the old organization and the new organization that assure the
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IANA that the transfer in mutually agreed, and that the new
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organization understands its responsibilities.
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It is also very helpful for the IANA to receive communications
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from other parties that may be concerned or affected by the
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transfer.
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4. Rights to Names
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1) Names and Trademarks
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In case of a dispute between domain name registrants as to the
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rights to a particular name, the registration authority shall have
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no role or responsibility other than to provide the contact
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information to both parties.
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The registration of a domain name does not have any Trademark
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status. It is up to the requestor to be sure he is not violating
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anyone else's Trademark.
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2) Country Codes
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The IANA is not in the business of deciding what is and what is
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not a country.
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Postel [Page 6]
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RFC 1591 Domain Name System Structure and Delegation March 1994
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The selection of the ISO 3166 list as a basis for country code
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top-level domain names was made with the knowledge that ISO has a
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procedure for determining which entities should be and should not
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be on that list.
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5. Security Considerations
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Security issues are not discussed in this memo.
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6. Acknowledgements
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Many people have made comments on draft version of these descriptions
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and procedures. Steve Goldstein and John Klensin have been
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particularly helpful.
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7. Author's Address
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Jon Postel
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USC/Information Sciences Institute
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4676 Admiralty Way
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Marina del Rey, CA 90292
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Phone: 310-822-1511
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Fax: 310-823-6714
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EMail: Postel@ISI.EDU
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7. References
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[1] Cooper, A., and J. Postel, "The US Domain", RFC 1480,
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USC/Information Sciences Institute, June 1993.
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[2] Reynolds, J., and J. Postel, "Assigned Numbers", STD 2, RFC 1340,
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USC/Information Sciences Institute, July 1992.
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[3] Mockapetris, P., "Domain Names - Concepts and Facilities", STD
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13, RFC 1034, USC/Information Sciences Institute, November 1987.
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[4] Mockapetris, P., "Domain Names - Implementation and
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Specification", STD 13, RFC 1035, USC/Information Sciences
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Institute, November 1987.
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[6] Partridge, C., "Mail Routing and the Domain System", STD 14, RFC
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974, CSNET CIC BBN, January 1986.
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[7] Braden, R., Editor, "Requirements for Internet Hosts --
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Application and Support", STD 3, RFC 1123, Internet Engineering
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Task Force, October 1989.
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Postel [Page 7]
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