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DNS - Domain Name System

The Domain Name System (DNS) helps users find their way around the Internet. Every computer on the Internet has a unique address, just like a telephone number, composed of a rather complicated string of numbers. This is called its "IP address" (IP standing for "Internet Protocol"). IP addresses are hard to remember. The DNS makes using the Internet easier by allowing a familiar string of letters (the domain name) to be used instead of the complex IP address. So instead of typing, you can type It is a mnemonic device that makes addresses easier to remember.

gTLD - Generic Top Level Domain

Most TLDs with three or more characters are referred to as generic TLDs, or gTLDs. They can be subdivided into two types: sponsored TLDs (sTLDs) and unsponsored TLDs (uTLDs).

IANA - Internet Assigned Numbers Authority

The IANA is the authority originally responsible for the overseeing IP address allocation, the coordination of the assignment of protocol parameters provided for in Internet technical standards, and the management of the DNS, including the delegation of top-level domains and oversight of the root name server system. Under ICANN, the IANA continues to distribute addresses to the Regional Internet Registries, coordinate with the IETF and others to assign protocol parameters, and oversee the operation of the DNS.

ICANN - The Internet Corporation for Assigned Names and Numbers

The Internet Corporation for Assigned Names and Numbers (ICANN) is an internationally organized, non-profit corporation that has responsibility for Internet Protocol (IP) address space allocation, protocol identifier assignment, generic (gTLD) and country code (ccTLD) Top Level Domain name system management, and root server system management functions. Originally, the Internet Assigned Numbers Authority (IANA) and other entities performed these services under U.S. Government contract. ICANN now performs the IANA function. As a private-public partnership, ICANN is dedicated to preserving the operational stability of the Internet; to promoting competition; to achieving broad representation of global Internet communities; and to developing policy appropriate to its mission through bottom-up, consensus-based processes. The DNS translates the domain name you type into the corresponding IP address, and connects you to your desired website.

IDNs - Internationalized Domain Names

IDNs are domain names that include characters used in the local representation of languages that are not written with the twenty-six letters of the basic Latin alphabet "A-Z". An IDN can contain Latin letters with diacritical marks, as in Greek, or may consist of characters from non-Latin scripts such as Arabic or Chinese. Many languages also use other types of digits than the European "0-9&". The basic Latin alphabet together with the European-Arabic digits are, for the purpose of domain names, termed "ASCII characters" (ASCII = American Standard Code for Information Interchange). These are also included in the broader range of "Unicode characters" that provides the basis for IDNs.

A domain name that only includes ASCII letters, digits, and hyphens is termed an "LDH label". Although the definitions of A-labels and LDH-labels overlap, a name consisting exclusively of LDH labels, such as "" is not an IDN.

IP - Internet Protocol

The communications protocol underlying the Internet, IP allows large, geographically diverse networks of computers to communicate with each other quickly and economically over a variety of physical links. An Internet Protocol Address is the numerical address by which a location in the Internet is identified. Computers on the Internet use IP addresses to route traffic and establish connections among themselves; people generally use the human-friendly names made possible by the Domain Name System.

ISP - Internet Service Provider

An ISP is a company, which provides access to the Internet to organizations and/or individuals. Access services provided by ISPs may include web hosting, email, VoIP (voice over IP), and support for many other applications.

RGP - Redemption Grace Period

The Redemption Grace Period is a 30-day period occurring after a registrar deletes a domain name. During this time, the original registrant has a chance to redeem the domain by paying a fee. If the fee is not paid during the grace period, then the domain name moves into Pending Delete status.


Domain names ending with .aero, .biz, .com, .coop, .info, .museum, .name, .net, .org, and .pro can be registered through many different competing companies known as registrars. In most cases, you only want to work directly with ICANN Accredited registrars. There are resellers, but does not use resellers for registering domain names.

The registrar you choose will ask you to provide various contact and technical information that makes up the registration. The registrar keeps records of the contact information and submits the technical information to a central directory known as the registry. This registry provides other computers on the Internet the information necessary to send you e-mail or to find your web site. You will also be required to enter a registration contract with the registrar, which sets forth the terms under which your registration is accepted and will be maintained.


The Registry is company that maintains the master database of all domain names registered in each Top Level Domain. The registry operator keeps the master database and generates a zone file which allows computers to route Internet traffic to and from top level domains anywhere in the world. An example of a registry is Verisign who maintains control over the .com and .net Top Level Domains. Internet users do not interact directly with registry operators; users can register names in TLDs, including .biz, .com, .info, .net, .name, and .org, by using an ICANN-Accredited Registrar.

Root Servers

Root servers contain the IP addresses of all the TLD registries, both global registries such as .com, .org, etc. and the 244 country-specific registries such as .fr (France), .cn (China), etc. This is critical information. If the information is not 100% correct or if it is ambiguous, it might not be possible to locate a key registry on the Internet. In DNS parlance, the information must be unique and authentic.

TLD - Top Level Domain

TLDs are the names at the top of the DNS naming hierarchy. They appear in domain names as the string of letters following the last dot ("."), such as "net" in "". The administrator for a TLD controls what second-level names are recognized in that TLD. The administrators of the root domain or root zone control what TLDs are recognized by the DNS. Commonly used TLDs include .com, .net, .edu, .jp, .de, etc.


WHOIS (pronounced "who is"; not an acronym) is an Internet protocol that is used to query databases to obtain information about the registration of a domain name (or IP address). ICANN's gTLD agreements require registries and registrars to offer an interactive web page and a port 43 WHOIS service providing free public access to data on registered names. Such data is commonly referred to as WHOIS data, and includes elements such as the domain registration creation and expiration dates, nameservers, and contact information for the registrant and designated administrative and technical contacts.

WHOIS services are typically used to identify domain holders for business purposes and to identify parties who are able to correct technical problems associated with the registered domain.