Top-level domain
Responsibility for management of most top-level domains is delegated to specific organizations by the ICANN, an Internet multi-stakeholder community, which operates the Internet Assigned Numbers Authority (IANA), and is in charge of maintaining the DNS root zone.
Originally, the top-level domain space was organized into three main groups: Countries, Categories, and Multiorganizations.
The authoritative list of current TLDs in the root zone is published at the IANA website at https://www.iana.org/domains/root/db/.
ICANN started to accept applications for IDN ccTLDs in November 2009,[6] and installed the first set into the Domain Names System in May 2010.
[citation needed] NATO considered none of the then-existing TLDs as adequately reflecting their status as an international organization.
[citation needed] Other historical TLDs are .cs for Czechoslovakia (now using .cz for Czech Republic and .sk for Slovakia), .dd for East Germany (using .de after reunification of Germany), .yu for SFR Yugoslavia and Serbia and Montenegro (now using .ba for Bosnia and Herzegovina, .hr for Croatia, .me for Montenegro, .mk for North Macedonia, .rs for Serbia and .si for Slovenia), .zr for Zaire (now .cd for the Democratic Republic of the Congo), and .an for Netherlands Antilles (now .aw for Aruba, .cw for Curaçao and .sx for Sint Maarten).
In contrast to these, the TLD .su has remained active despite the collapse of the Soviet Union that it represents.
Under the chairmanship of Nigel Roberts, ICANN's ccNSO is working on a policy for the retirement of ccTLDs that have been removed from ISO 3166.
Site owners argued that a similar TLD should be made available for adult and pornographic websites to settle the dispute of obscene content on the Internet, to address the responsibility of US service providers under the US Communications Decency Act of 1996.
[26] ICANN rejected several proposed domains to include .home and .corp due to conflicts regarding gTLDs that are in use in internal networks.
For example, querying org itself (with a tool such as dig, host, or nslookup) returns information on its nameservers: Dotless domains are top-level domains that take advantage of that fact, and implement A, AAAA or MX DNS records to serve webpages or allow incoming email directly on a TLD – for example, a webpage hosted on http://example/, or an email address user@example.
[30] ICANN's Security and Stability Advisory Committee (SSAC) additionally claims that SMTP "requires at least two labels in the FQDN of a mail address" and, as such, mail servers would reject emails to addresses with dotless domains.
Most of these networks have long since ceased to exist, and although UUCP still gets significant use in parts of the world where Internet infrastructure has not yet become well established, it subsequently transitioned to using Internet domain names, and pseudo-domains now largely survive as historical relics.
