INTERNET

 INTRODUCTION TO INTERNET

Question: What is the Internet?

Answer: A global system of interconnected computers, using a standardized Internet Protocol suite for communication and sharing information is called the Internet.

Internet, a system architecture that has revolutionized communications and methods of commerce by allowing various computer networks around the world to interconnect. Sometimes referred to as a “network of networks,” the Internet emerged in the United States in the 1970s but did not become visible to the general public until the early 1990s. By 2020, approximately 4.5 billion people, or more than half of the world’s population, were estimated to have access to the Internet.

Question: What is ISP?

Answer: ISP stands for Internet Service Provider. This helps in providing direct access for using the internet from your office or home, connected through landlines. With the introduction of Wi-fi and broadband, connecting to the Internet has become wireless.

Example:- BSNL, Airtel, Jio, etc.

Question: What is the World Wide Web?

Answer: World Wide Web or ‘WWW’ is a collection of web pages which can easily be published on the Internet and read by millions of its users. The World Wide Web (WWW) is an internet based service, which uses common set of rules known as Protocols, to distribute documents across the Internet in a standard way. 

The World Wide Web, or ‘Web’ is a part of the Internet. The Web is viewed through web browser softwares such as Google Chrome, Internet Explorer, Mozilla Firefox etc. Using browsers one can access the digital libraries containing innumerable articles, journals, e-books, news, tutorials stored in the form of web pages on computers around the world called Web Servers. Today thousands of web pages/websites are added to the WWW every hour.

Difference between Internet and WWW

The Internet is known as “interconnection of computer networks”. The Internet is a massive network of networks. It connects millions of computers together globally, forming a network in which any computer can communicate with any other computer as long as they are both connected to the Internet. Information that travels over the Internet does so via a variety of languages known as protocols.

The World Wide Web, or “Web” for short, or simply Web, is a massive collection of digital pages to access information over the Internet. The Web uses the HTTP protocol, to transmit data and allows applications to communicate in order to exchange business logic. The Web also uses browsers, such as Internet Explorer or Firefox, to access Web documents called Web pages that are linked to each other via hyperlinks. Web documents also contain graphics, sounds, text and video.

Search Engines

Search engines are the programs which are needed to extract the information from the internet. They play a very important role in our daily routine, as today for each and every information we are dependent on internet. 

    Web search engines work with the help of two programs, Spider which fetches as many documents as possible. Another program, called an indexer, reads the documents and creates an index based on the words contained in each document. Each search engine uses an algorithm to create its indices such that, only related results for specified keywords is stored and returns a list of the documents where the keywords were found.

A search engine works in the following order:

1. Web crawling: Web search engines work by storing information about many web

pages. These pages are retrieved by the program known as Web crawler - which

follows every link on the site. Web crawler may also be called a Web spider.

2. Indexing: Indexing also known as web indexing, it stores data to facilitate fast and

accurate information retrieval.

3. Searching: A web search query fetches the result from the web search engine entered

by the user to meet his information needs.

Question: What is an IP address?

Answer: The Internet Protocol address is a numerical identification code assigned for any device connected to a network. It acts as an identification interface for Internet users.

An IP address is a unique address that identifies a device on the internet or a local network. IP stands for "Internet Protocol," which is the set of rules governing the format of data sent via the internet or local network.

An IP address is a string of numbers separated by periods. IP addresses are expressed as a set of four numbers — an example address might be 192.158.1.38. Each number in the set can range from 0 to 255. So, the full IP addressing range goes from 0.0.0.0 to 255.255.255.255.

How do IP addresses work

Internet Protocol works the same way as any other language, by communicating using set guidelines to pass information. All devices find, send, and exchange information with other connected devices using this protocol. By speaking the same language, any computer in any location can talk to one another.

The use of IP addresses typically happens behind the scenes. The process works like this:

1. 1. Your device indirectly connects to the internet by connecting at first to a network connected to the internet, which then grants your device access to the internet.
2. 2. When you are at home, that network will probably be your Internet Service Provider (ISP). At work, it will be your company network.
3. 3. Your IP address is assigned to your device by your ISP.
4. 4. Your internet activity goes through the ISP, and they route it back to you, using your IP address. Since they are giving you access to the internet, it is their role to assign an IP address to your device.
5. 5. However, your IP address can change. For example, turning your modem or router on or off can change it. Or you can contact your ISP, and they can change it for you.
6. 6. When you are out and about – for example, traveling – and you take your device with you, your home IP address does not come with you. This is because you will be using another network (Wi-Fi at a hotel, airport, or coffee shop, etc.) to access the internet and will be using a different (and temporary) IP address, assigned to you by the ISP of the hotel, airport or coffee shop.

As the process implies, there are different types of IP addresses, which we explore below.

Types of IP addresses

There are different categories of IP addresses, and within each category, different types.

Consumer IP addresses

Every individual or business with an internet service plan will have two types of IP addresses: their private IP addresses and their public IP address. The terms public and private relate to the network location — that is, a private IP address is used inside a network, while a public one is used outside a network.

Private IP addresses

Every device that connects to your internet network has a private IP address. This includes computers, smartphones, and tablets but also any Bluetooth-enabled devices like speakers, printers, or smart TVs. With the growing internet of things, the number of private IP addresses you have at home is probably growing. Your router needs a way to identify these items separately, and many items need a way to recognize each other. Therefore, your router generates private IP addresses that are unique identifiers for each device that differentiate them on the network.

Public IP addresses

A public IP address is the primary address associated with your whole network. While each connected device has its own IP address, they are also included within the main IP address for your network. As described above, your public IP address is provided to your router by your ISP. Typically, ISPs have a large pool of IP addresses that they distribute to their customers. Your public IP address is the address that all the devices outside your internet network will use to recognize your network.

Public IP addresses

Public IP addresses come in two forms – dynamic and static.

Dynamic IP addresses

Dynamic IP addresses change automatically and regularly. ISPs buy a large pool of IP addresses and assign them automatically to their customers. Periodically, they re-assign them and put the older IP addresses back into the pool to be used for other customers. The rationale for this approach is to generate cost savings for the ISP. Automating the regular movement of IP addresses means they don’t have to carry out specific actions to re-establish a customer's IP address if they move home, for example. There are security benefits, too, because a changing IP address makes it harder for criminals to hack into your network interface.

Static IP addresses

In contrast to dynamic IP addresses, static addresses remain consistent. Once the network assigns an IP address, it remains the same. Most individuals and businesses do not need a static IP address, but for businesses that plan to host their own server, it is crucial to have one. This is because a static IP address ensures that websites and email addresses tied to it will have a consistent IP address — vital if you want other devices to be able to find them consistently on the web.

This leads to the next point – which is the two types of website IP addresses.

There are two types of website IP addresses

For website owners who don’t host their own server, and instead rely on a web hosting package – which is the case for most websites – there are two types of website IP addresses. These are shared and dedicated.

Shared IP addresses

Websites that rely on shared hosting plans from web hosting providers will typically be one of many websites hosted on the same server. This tends to be the case for individual websites or SME websites, where traffic volumes are manageable, and the sites themselves are limited in terms of the number of pages, etc. Websites hosted in this way will have shared IP addresses.

Dedicated IP addresses

Some web hosting plans have the option to purchase a dedicated IP address (or addresses). This can make obtaining an SSL certificate easier and allows you to run your own File Transfer Protocol (FTP) server. This makes it easier to share and transfer files with multiple people within an organization and allow anonymous FTP sharing options. A dedicated IP address also allows you to access your website using the IP address alone rather than the domain name — useful if you want to build and test it before registering your domain.

Question: What is a Web Browser?

Answer: A web browser is a software application for accessing the information on the World Wide Web. The commonly used web browsers include Google Chrome, Internet Explorer, Mozilla Firefox, etc.

Ways To Connect To Internet

The different ways in which one can connect to the Internet are discussed below in brief:

• Dial-Up – In such connections, users are required to link their phone line to a computer to access the Internet. Under this connection, the user cannot make or receive phone calls through tier home phone service.

• Broadband – Provided either through cable or phone companies, Broadband is a high-speed internet connection which is widely used today.
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• Wireless Connection – Wi-fi and Mobile service providers fall under this category. Internet connectivity is made via radio waves and the Internet can be connected anywhere, irrespective of the location. Given below are a few examples of wireless connection:
• Wi-fi – Wireless Fidelity or wi-fi allows high-speed internet connectivity without the use of wires
• Mobile Phones – All smartphones are now equipped with an option for Internet connectivity which can be availed using Internet vouchers and packs. No external connection or wire is required for these
• Satellite – Where broadband connections are unavailable, satellites are used for wireless Internet connectivity
• Integrated Services Digital Network – ISDN allows users to sent audio or video data using telephone lines

Web Servers

2.1 What is a Server?

A server is a computer that provides data to other computers. The entire structure of the Internet is based upon a client-server model. Web server helps to deliver web content that can be accessed through the Internet. The most common use of web servers is to host websites, as the internet is not only used to fetch the information but there are other uses such as gaming, data storage or running business applications.

    The primary job of a web server is to deliver web pages to clients. The communication between the client node and server node takes place using the Hypertext Transfer Protocol (HTTP). The delivered web pages include images, style sheets and scripts in addition to text content.

Server Software

A web server commonly known as HTTP server or application server is a program that serves content using the HTTP protocol. This content is generally in the form of HTML documents, images, and other web resources, but can include any type of file. The content served by the web server can be pre-existing (static content) or generated on the fly (dynamic content).

1. Apache web server - the HTTP web server: Apache Software Foundation developed the free and open source web server and can be installed and made to work on almost all operating systems including Linux, Unix, Windows, FreeBSD, Mac OS X and more. Almost, 60% of the web server machines run the Apache web server.

2. Apache Tomcat: Apache Tomcat is free and open source web server that can run on different operating systems like Linux, Unix, Windows, Mac OS X, Free BSD. It was developed to support servlets and JSP scripts. It can serve as a standalone server.

Services Provided by the Servers

Today many services are being provided by the Web Server. Many of the servers are based on Cloud computing which is popular amongst the researchers, scientists & entrepreneurs. 

    Cloud Computing is distributed computing over a network, and has the ability to run a program or application on many connected computers at the same time. It is used, where various computing concepts that involve a large number of computers are connected via real-time communication network such as the Internet.

Various services provided by the Web server are:

1. Cost Efficient: Web server is the most cost efficient method to use, maintain and upgrade. Traditional desktop software costs companies a lot in terms of finance. On the other hand, it is available at much cheaper rates. Besides, there are many onetime-payment, pay-as-you-go and other scalable options available, which makes it very reasonable for the company.

2. Resource Sharing: Web Server has the capability to store unlimited information such as Google Drives, Cloud computing etc. The space where the data can be stored is shared by the other users at the same time like hard disk can be shared on physical network as LAN.

3. Data Sharing: With the help of web servers one can easily access the information from anywhere, where there is an Internet connection using Google docs such as Documents, Excel sheets, Drawings, Powerpoint presentations etc.

4. Backup and Recovery: As all the data now a days is stored on web servers, backing it up and restoring the same is relatively much easier than storing the same on a physical device. Hence, the entire process of backup and recovery much simpler than other traditional methods of data storage.

Types of Servers

1. Mail Server: Mail Servers provides a centrally-located pool of disk space for network users to store and share various documents in the form of emails. Since, all the data is stored in one location, administrators need only backup files from one computer. 

2. Application Server: An application server acts as a set of components accessible to the software developer through an API defined by the platform itself. For Web applications, these components are usually performed in the same running environment as its web server(s), and their main job is to support the construction of dynamic pages.

3. File Transfer Protocol (FTP) Server: FTP uses separate control and data connections between the client and the server. FTP users may authenticate themselves in the form of a username and password, but can connect anonymously if the server is configured to allow it. For secure transmission username and password must be encrypted using FTP and SSL.

4. Database Server: A database server is a computer program that provides database services to other computer programs or computers using client-server model. Database management systems frequently provide database server functionality, and some DBMSs (e.g., MySQL) depend on the client-server model for database access.

Such a server is accessed either through a “front end” running on the user’s computer where the request is made or the “back end” where the request is served such as data analysis and storage.

5. Domain Name System (DNS) Server: A name server is a computer server that hosts a network service for providing responses to queries. It maps a numeric identification or addressing component. This service is performed by the server in response to a network service protocol request.

The primary function of these DNS servers is the translation (resolution) of human memorable domain names and hostnames into the corresponding numeric Internet Protocol (IP) addresses. The secondary function of DNS is to recognize a name space of the Internet, used to identify and locate computer systems and resources on the Internet.

Web Site

The collection of web pages on the World Wide Web that is accessed by its own Internet address is called a Web site. Thus, a Web site is a collection of related Web pages. Each Web site contains a home page and contains other additional pages. Each Web site is owned and updated by an individual, company, or an organization. Web is a dynamically moving and changing entity, today web sites generally change on a daily or even hourly basis.

How Website is different from Portal?

Web portal is a medium by which users access the resources, while a website is a destination in itself. Portals and websites are distinct entities which are linked together, but they should not replace each other. A website is also a portal, if it broadcast information from different independent resources where as Web Portal refers to a website or services that provide varied resources and services such as email, forums, search engines and online shopping malls.

Some of the web portals are AOL, iGoogle, Yahoo and even more.

A website refers to a location or a domain name hosted on a server which is accessible via internet. It is a collection of web pages, images, videos which are addressed relative to a Uniform Resource Locator (URL). Websites provide content from independent resources to specific audience. The content of the website is generally focused & contains the material needed to be accessed.

Components of Website

1. Contents of a Web Page: A webpage of a website must contain the basic elements such as Page title, URL, file name, header, footer, navigation, web page content are all parts to the composition of a web page.

2. Website Graphics: Always use web graphics which have been optimized for optimum download speed, as the web hosting space affects the performance of the website.

3. Heading of the site: Headings in a website play a crucial role as they not only present a clear structure of the web page to the audience and help the search engines to retrieve the required information.

4. Effective Colour Contrast: As the websites are used to retrieve the information related to specific purpose or topic. It is very important to take care of the presentation of the contents of the sites. So that, website visitors must not have any difficulty in reading a web page. As some times when we pick a colour scheme for our website we forget that there are people with poor vision and colour deficiencies.

Webpage

A Web page also known as Electronic Page, is a part of the World Wide Web. It is just like a page in a book. The basic unit of every Web site or document on the Web is a Web page containing the information.

Web Browser

A browser is a software that lets you view web pages, graphics and the online content. Browser software is specifically designed to convert HTML and XML into readable documents.

The most popular web browsers are: Google Chrome, Firefox, Internet Explorer, Safari, Opera and UC Browser.

Construction of Website

Steps to build a Website

Step 1: Hosting

The first step in constructing a website is to decide about the web hosting provider for your site.

There are several types of Web hosting options you can choose from such as:

Free Web hosts: Most people want to go for free Web hosting. On one hand it is free but on the other hand, you don’t always get much space, due to low bandwidth.

Search a Web Hosting Provider: These are the links to other sites for finding a good host for your site.

Step 2: Domain Name

You can plan your website in two ways: using a domain name and without using a domain

name. You can put up a site on free hosting or even paid hosting plans. A domain name

provides extra branding for your site and makes it easier for people to remember the

URL.

Step 3: Plan Your Website

After deciding the domain and your URL, you can start planning your site. You need to decide the audience aimed at.

Select the type of site: Most websites are either news/information, product, or reference

sites. Each has a different focus. A site must have formal language, where as a personal

site can use slang and an informal tone.

Step 4: Build Your Website Page by Page

For building a website you need to work on one page at a time. To build your site you

should be familiar with the key elements of the site as discussed above.

Step 5: Publish Your Website

After the completion of the design now it is the time to publish your website on web. You

can do this either with the tools using your hosting service or with FTP clients. Knowing

which you can use depends upon your hosting provider.

Step 6: Promote Your Website

There are many ways to promote a website such as web search engine, word of mouth,

email, and advertising. You build your Web content so that it ranks well in commonly

used search engines. This can be difficult, but it is inexpensive and can result in good

results if you work at it.

Step 7: Maintain Your Website

Maintenance is the last step of constructing a site which helps in keeping your site updated

with the latest trends of market. In order to keep your site going well and looking good, you need to test your site frequently. And you should also work on content development

on a regular basis.