The origin of the Internet dates back to 1969/1970 when 4 computers were first connected to each other over the phone lines. These four computers were located at:

• University of California Santa Barbara
• University of California at Los Angeles
• Stanford Research Institute – Los Angeles
• University of Utah at Salt Lake

20 years of concerted effort by scientists and engineers have produced today’s all-purpose, global network for high-speed digital communication.

Each computer on the Internet is called an Internet host or a host machine. Each host machine has a special Internet protocol address (IP address) that uniquely identifies that computer. IP addresses were never designed to be seen by human eyes. They are an address that is interpreted by a computer. An example of an IP address is:
205.213.164.10

Since numbers are easy for a computer to work with but difficult for humans, most host machines have a Domain Name Service (DNS) address. For instance, the domain name service address of the IP address listed above is:

depts.alverno.edu

Each Domain Name Service address is made up of two parts – the institution site name (alverno) and the Top-Level Domain (TLD) (edu). The Top-Level Domain identifies the type of site on which the host machine resides.

Sometimes the TLD are referred to as "domains". This can be very confusing, since a domain is also the name for a DNS. For instance, alverno.edu is a domain. The most common TLD, or top level domains, are listed on the right.

Other TLD names identify geographical locations by country – such as:

• .au - Australia
• .ca - Canada
• .dk - Denmark
• .fr - France
• .de - Germany
• .uk - Great Britain
• .hk - Hong Kong

Newly added Top-Level Domains include:

TLD Name	Type of Organization
.biz	Businesses
.info	For all users
.aero	For the air-transport industry
.coop	For cooperatives
.museum	For museums
.name	For individuals
.pro	For professions

Top-Level Domain Names help users identify what type of site they are visiting