Internet is the world’s largest network that connects millions of people and billions of computers around the world. It is a network of networks that consists of millions of private, public, academic, business and government networks together using a common protocol (TCP/IP). The computers on the internet are connected to each other through cables, phone lines, satellites, and other connecting devices.

Internet was first introduced by the Department of Defence of the USA as Advanced Research Project Agency (ARPA) in 1969. ARPANet was the world’s first computer network. Actually, it was a very small network that covered three universities and one government agency. On October 1, 1979, the first time, any message was sent in a network. At first, this network was named ARPANet (Advanced Research Project Agency Network).

Later in 1983, ARPANet split into MILNet (Military Network), which serves the Defence community and ARPANet served the research and education community. Likewise, many companies started to use their own network and thus Internet came to its existence. It is called the network of networks. It is globally expanded and growing day by day.

In Nepal, Mercantile company started the Internet service for the first time in 1994. Internet is not governed by a single organization but by a group of bodies or companies like IAB (Internet Advisory Board), ISOC (Internet Society), IETF (Internet Engineering Task Force), INIC (Internet Network Information Center), and IRTF (Internet Research Task Force).

As the internet can be used by anyone throughout the world, Intranet is used only by certain authorized people. In other words, we can say the Intranet is another form of the Internet that is utilized only by the related authorized class or people for the sake of safety and security. It is generally used by private companies, security departments like Nepal police, Nepal military force, Home Ministry, and so on. Unlike the Internet, it is a private network service.

It is a computer network that allows controlled access from the outside, for specific business or educational purposes. It can be understood as an Intranet mapped on to public Internet.

The companies or organizations that provide Internet facilities are known as Internet Service providers. They provide Internet facilities on the basis of certain fixed charges. They provide two types of services: Limited and unlimited Service.

Internet browser is the software that provides a platform to run web pages or websites. it is also known as client software. Internet Explorer, Netscape Navigator, Mozilla Firefox are the most common browsers to run the Internet.

In today’s world, the Internet is playing a vital role in every field. The importance of the Internet is increasing day by day. Nowadays Internet is being used in many fields like education, health, business, communication, and entertainment. Some of the services provided by the internet are as follows:

Email stands for Electronic Mail. It is the service used to share letters with the help of electronic devices like computers. Earlier, the letter which was sent through the post office is sent through the internet. Email is one of the most popular services on the Internet. Using email programs like Outlook, Gmail, email can e sent and received. The messages sent by a person using the email program reach the recipient’s mailbox directly and can be received from the mailbox.

Telnet allows an Internet user to log into another computer on the internet from his or her local computer. This service provides a facility for sharing processing power and enables sharing software and hardware devices. To work in Telnet, Telnet commands are required.

FTP is an application-level protocol that allows a user to move a file from one computer to another computer in a network environment. Whatever stored in a computer can be easily moved to another computer using this service. It is also a tool responsible for downloading and uploading.

Views and News or USENET is the BBS (Bulletin Board Service) of the Internet. The message in the BBS is organized into thousands of newsgroups that cover specific areas of interest.

The WWW was originated in the 1990s. In 1991, CERN (Counsel European Research Nuclear) released WWW. This is the most popular service available on the Internet. It is a subset of the internet and it presents text, images, animation, video, sound, and other multimedia elements in a single interface. The WWW contains a vast collection of linked multimedia pages that are always changing.

It is one of the service of the Internet that uses and application layer protocol and communicate with people in the form of text. IRC is a computer program that users can install on their system.

It uses the same technology as IRC but also provides sound and video pictures. It enables direct face-to-face communication across networks.

Internet is also known as the ocean of information. There is a huge amount of information available on the Internet.

Nowadays Internet has become the main source of advertisement for big companies. Newspapers, magazines, radio, TV are used for advertisement, likewise, the Internet is the main medium of advertisement today.

Many companies tag their manufactured products along with price lists on different websites on the Internet. We can order the required product and can also pay the price online through the Internet.

It is a method of sharing our ideas and views in real-time through the Internet. Through chat rooms, we can share information on any subject(s) with any person around the world.

Nowadays, the Internet is the best medium of entertainment. Downloading games, playing online, watching movies and videos are some of the examples of entertainment through the Internet.