Country code top-level domain

A country code top-level domain (ccTLD) is an Internet top-level domain generally used or reserved for a country, a sovereign state, or a dependent territory.

All ASCII ccTLD identifiers are two letters long, and all two-letter top-level domains are ccTLDs. In 2010, the Internet Assigned Numbers Authority (IANA) began implementing internationalized country code TLDs, consisting of language-native characters when displayed in an end-user application. Creation and delegation of ccTLDs is described in RFC 1591, corresponding to ISO 3166-1 alpha-2 country codes.

Types

As of 2015, IANA distinguishes the following groups of top-level domains:

Delegation and management

IANA is responsible for determining an appropriate trustee for each ccTLD. Administration and control is then delegated to that trustee, which is responsible for the policies and operation of the domain. The current delegation can be determined from IANA's list of ccTLDs. Individual ccTLDs may have varying requirements and fees for registering subdomains. There may be a local presence requirement (for instance, citizenship or other connection to the ccTLD), as for example the Canadian (ca) and German (de) domains, or registration may be open.

Top-level domain

A top-level domain (TLD) is one of the domains at the highest level in the hierarchical Domain Name System of the Internet. The top-level domain names are installed in the root zone of the name space. For all domains in lower levels, it is the last part of the domain name, that is, the last label of a fully qualified domain name. For example, in the domain name www.example.com, the top-level domain is com. Responsibility for management of most top-level domains is delegated to specific organizations by the Internet Corporation for Assigned Names and Numbers (ICANN), which operates the Internet Assigned Numbers Authority (IANA), and is in charge of maintaining the DNS root zone.

History

Originally, the top-level domain space was organized into three main groups: Countries, Categories, and Multiorganizations. An additional temporary group consisted of only the initial DNS domain, arpa, and was intended for transitional purposes toward the stabilization of the domain name system.

Country code

Country Codes are short alphabetic or numeric geographical codes (geocodes) developed to represent countries and dependent areas, for use in data processing and communications. Several different systems have been developed to do this. The best known of these is ISO 3166-1. The term country code frequently refers to international dialing codes, the E.164 country calling codes.

ISO 3166-1

This standard defines for most of the countries and dependent areas in the world:

The two-letter codes are used as the basis for some other codes or applications, for example,

For more applications see ISO 3166-1 alpha-2.

Other country codes

List of country calling codes

Country calling codes or country dial in codes are telephone dialing prefixes for the member countries of the International Telecommunication Union (ITU). They are defined by the ITU-T in standards E.123 and E.164. The prefixes enable international direct dialing (IDD), and are also referred to as international subscriber dialing (ISD) codes.

Country codes are a component of the international telephone numbering plan, and are necessary only when dialing a telephone number to establish a call to another country. Country codes are dialed before the national telephone number. By convention, international telephone numbers are represented by prefixing the country code with a plus sign (+), which also indicates to the subscriber that the local international dialing prefix must first be dialed. For example, the international dialing prefix in all countries belonging to the North American Numbering Plan is 011, while it is 00 in most European, Asian and African countries. On GSM (cellular) networks, the prefix may automatically be inserted when the user prefixes a dialed number with the plus sign.