Domain Names

Domain names

• Introduction
• Glossary of Terms
• F.A.Q.
• Resources
• Further Reading

Introduction

The domain name system (DNS) was created in the early 1980's in order to simplify navigation on the Internet. Before then, each computer on the Internet was identified by a complex set of numbers called an Internet Protocol (IP) address. Now, instead of typing in a complex set of numbers, we type in text-based domain names and the computer takes us to the corresponding IP address. The system is global; to maintain reliability, it has to make sure that no two IP addresses or corresponding domain names are the same. The DNS is thus of critical importance to the way the Internet operates: if it fails, websites and email addresses cannot be located.

Glossary of Terms

Domain Names

The text-based mnemonic address associated with a numerical IP address. For example, 'www.google.com' is the domain name associated with the IP address 216.239.41.99. The 'www' part of the domain name indicates the server, the 'google' part is a name chosen by the site owner and the '.com' part indicates the Domain Name Registry under which the site is registered. Together, they make one domain name.

ICANN

The Internet Corporation for Assigned Names and Numbers (ICANN) is responsible for managing the Domain Name System to ensure that every address is unique and that all users of the Internet can find all valid addresses. It does this by overseeing the distribution of unique IP addresses and domain names. It also ensures that each domain name maps to the correct IP address.

IP Address

A 32-bit numerical address which identifies the sender and receiver of information sent over the Internet. Without a unique IP address, information cannot be sent or received over the Internet.

Mnemonic

A device used to assist in the process of memorization. For example, it is easier to remember the mnemonic domain name 'www.google.com' than it is to remember the IP address 216.239.41.99 which the domain name represents.

Domain Name Registry

An organization with the authority to assign domain names within one or more top level domains. The authority to deal with one or more top level domains is provided by ICANN, the Internet Corporation for Assigned Names and Numbers. Registries are required to make their domain name registrations available to the public through the WHOIS database.

Domain Name Registrar

A company whose business it is to register domain names with a particular registry. Registrars are intermediaries between domain name holders and registries. They charge end users for their registration services and pay a fee to the registries for the right to engage in this business.

Domain Name Registrant

The individual or organization that registers a specific domain name with a Registrar. The registrant then receives the right to use a domain name for a specified period of time after which it can usually be renewed.

Reseller

A person or entity that provides registration services for domain names to the public without being certified as a Registrar by a Registry. The Reseller uses the services of a certified Registrar to have its registration transactions processed.

Top Level Domain (TLD):

The uppermost in the hierarchy of domains, the TLD is identified by the letters which follow the dot in a web address like .com or .ca. Each TLD is administered by a given Registry, under the umbrella of ICANN. There are two categories:

Generic Top Level Domain (gTLD)

A TLD which is global and open to registrants around the world. E.g. .com, .net or .org. Some other new and more limited top level domains include .museum (museums) or .mil (U.S. military). Note that .com is not restricted to commercial entities.

Country Code Top Level Domain (ccTLD)

A two-letter TLD which is associated with a particular country and usually controlled by a national registry. ccTLDs usually require that their registrants be located in that country, unlike gTLDs which are open to anyone. It is possible for a country to cede its rights to a national ccTLD as Tuvalu did with the ccTLD '.tv'.

Uniform Resource Locator (URL):

A string of characters representing the location of a resource on the Internet; also known as a "web address." The first part of the address identifies the protocol being used (usually HTTP) and the second part indicates the domain name attached to an IP address where the resource is located. The URL for CIPPIC's home page, for example, is www.cippic.ca.

F.A.Q.

What is the Domain Name System (DNS)?

The Domain Name System (DNS) translates domain names to Internet Protocol (IP) addresses. Every computer on the Internet has a unique IP address. For example, if you type "216.239.41.99" into the address bar at the top of your browser, you will be taken to the Google website. Because that number is difficult to remember, we assign a mnemonic name to it. That way, instead of having to remember "216.239.41.99" a user can simply type in "www.google.com".

Who administers the Domain Name System (DNS)?

The domain name system is administered by The Internet Corporation for Assigned Names and Numbers (ICANN). ICANN is primarily responsible for ensuring that IP addresses correspond with the correct domain name and for generic Top Level Domain (gTLD) and country code Top Level Domain (ccTLD) name system management.

The management and distribution of both generic and country code Top Level Domains (TLD) is handled by Registries. For example, the Canadian Internet Registration Authority (CIRA) is responsible for operating the ".ca" ccTLD and VeriSign Global Registry Services manages the operation of the ".com" and ".net" gTLDs.

Currently, there are 12 generic TLDs operated by various Registries. There are various restrictions (set out in the following table) on who may obtain a specific gTLD.

There are 247 country code TLDs. The requirements for obtaining ccTLD vary from country to country. The Canadian presence requirements are outlined by CIRA.

Domain names are generally distributed by Registrars to Registrants, who can be individuals or organizations. The Registrar keeps records of the Registrants' contact information, submits the technical information to the Registry and publishes the contact information of Registrants through WHOIS.

Registrants may also obtain domain names through Resellers. Resellers are organizations are not certified as a Registrar, but instead act as an intermediary between the Registrant and the Registrar. Typically, Resellers offer value added services, such as web hosting, URL forwarding, email forwarding, and search engine listing.

What information is collected when registering a domain name?

In addition to certain technical information (e.g. IP address of primary name server) and information required for billing purposes (e.g. credit card number, billing address, etc