IANA Report on Deletion of the .zr Top-Level Domain
(20 June 2001)

IANA Report

Subject: Deletion of .zr Top-Level Domain
Date: 20 June 2001

The Internet Assigned Numbers Authority (the IANA) is responsible for various administrative functions associated with management of the Internet's domain-name system root zone, including reviewing the appropriateness of changes to the content of the root zone as the Internet evolves and preparing reports on requested changes. This report gives the findings and conclusions of the IANA in connection with the deletion of the top-level domain .zr, which was the two-letter code associated with the country formerly known as Zaire.

Factual and Procedural Background

All two-letter top-level domains in the Internet's domain-name system are "country-code top-level domains." The names of these domains are taken from the two-letter code elements ("alpha-2 codes") shown on the ISO 3166-1 list maintained by the ISO 3166 Maintenance Agency (ISO 3166/MA). The ISO 3166-1 list is used worldwide in many applications involving coded information concerning names of countries and of physically separated dependent territories.

Until 1997, the ISO 3166-1 list included the alpha-2 code "zr" as the designation of the country of Zaire. In that year, after the name of Zaire was changed to the "Democratic Republic of the Congo," the ISO 3166/MA revised the alpha-2 designation for the country on the ISO 3166-1 list from "zr" to "cd". The alpha-2 code "zr" was transferred from the ISO 3166-1 list to the ISO 3166/MA's transitionally reserved list. The reserved code list specifies that "[transitionally reserved] code elements may be used only during a transition period while new code elements that may have replaced them are taken into use."

The IANA delegated the .cd top-level domain to the manager of the .zr top-level domain on 20 August 1997. Given that "zr" was being removed from the ISO 3166-1 list, the manager performed a transition, populating the .cd top-level domain and emptying the .zr top-level domain. By an 11 March 2001 message to the IANA, the .zr manager stated that the .zr top-level domain had been emptied in preparation for its deletion from the root zone.


The IANA is responsible for various functions associated with management of the root zone of the Internet domain-name system. Consistent with those responsibilities, the IANA publishes reports such as this one to document its evaluation of significant issues pertinent to root-zone management.

The policies followed in connection with the delegation of Internet top-level domains are summarized in "Internet Domain Name System Structure and Delegation" (ICP-1), which was issued in May 1999.

Because the IANA is not in the business of assessing whether or not particular areas are "countries," the policy set forth in ICP-1 for delegation matters has been to simply refer to the ISO 3166-1 list as an independent and authoritative source of two-letter abbreviations for countries and areas. (There are a small number of two-letter codes not on the ISO 3166-1 list that are delegated as country-code top-level domains for historic reasons, as described in detail in the IANA's 22 March 2000 "Report on Request for Delegation of .ps Top-Level Domain.")

When an alpha-2 code for a country is changed on the ISO 3166-1 list, the IANA's historical practice has been to set up a top-level domain with the new code and to delegate it to the same manager as the existing top-level domain, with the expectation that a transition will occur and that the deprecated top-level domain will be deleted once the migration is completed.

The migration of .zr has been completed, with all sub-domains within .zr having been removed. Accordingly, deletion of the .zr top-level domain is now appropriate.


The IANA concludes that the .zr top-level domain should be deleted from the root zone.

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