When you purchase (or subscribe to) Internet service, you pay an Internet Service Provider (ISP) for a connection. When you use the Internet, you connect to your[r]
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Lesson 5: Surfing the World Wide Web
Lesson Objectives
In this lesson, you will use a browser to surf the World Wide Web. On completion you will understand: the difference between the World Wide Web and the Internet
the domain name system how to use a browser browser tabs and hyperlinks uploading and downloading browser navigation buttons how to set a home page how to use bookmarks standard web page features
What Is the Internet?
Objective 31.1
You use the Internet all the time – doing research, playing games, watching videos, or chatting with friends. You type in an address, or click a link, and pages of text, color, images and embedded audio and video files appear on the screen
Where does all the information come from? And how does it reach your computer? The answer is through a series of networks
The Internet is a Network
The Internet is a tremendous global network. That means, it is a collection of hardware. It consists of wires, routers, switches, microwave links, servers, and communication protocols
In fact, the Internet is so large it is made of many smaller networks which are connected together so that they can communicate and share information
The Internet functions in much the same way as your school network or even your home network
Clients and Servers
On the Internet (as on any network), some computers function as clients and others function as servers
A client is any computer that requests a service or resource (such as a document or web page) from another computer on the network
A server is any computer that provides services or resources to other computers (clients) that request them.
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There are many types of servers used on the Internet – web servers, file servers, name servers, mail servers, news servers and even time servers to name a few
Internet Service
Because the Internet is so large, companies, schools and individual users do not connect to it directly; instead, they connect to the Internet through a middleman called a service provider
When you purchase (or subscribe to) Internet service, you pay an Internet Service Provider (ISP) for a connection. When you use the Internet, you connect to your ISP's network, which in turn is connected to the Internet (and all the smaller networks connected to it)
IP Address
Every computer on a network must have an address that identifies it and lets other computers on the network communicate with it. Your ISP gives you an IP address when you sign up for Internet service and your computer uses this address whenever you connect to the Internet
Finding Computers on the Internet
Objective 31.2
Every computer connected to the Internet has a unique IP address. This means that web servers (the computers that host web sites) must have IP addresses too. To communicate with a computer on the network, you must know its IP address
Have you ever typed an IP address into the address bar of your browser? Chances are you haven't
Instead, you type a textbased web site address (called a URL) into the browser address bar. For example, you type www.ccilearning.com in the browser address bar to visit the CCI Learning web site
How does your computer know the IP address of the CCI Learning web server when all you type into the address bar is the web site address?
The answer is by using the Domain Name System (DNS)
Here’s a Tip:
A Uniform Resource Locator (URL) is a web site address that includes a domain name
Domain Name System (DNS)
The Domain Name System (DNS) is a service that keeps track of the specific IP addresses of web servers around the Internet and matches or “maps” those IP addresses to the textbased names we enter into the address bars of our browsers. These textbased names are called domain names.
DNS resolves textbased domain names into their IP addresses. For example, when you type www.google.com in your browser’s address, your computer contacts the web server at the IP address 64.233.177.99. In other words: 64.233.177.99 = www.google.com
Both the domain name and the IP address refer to the same resource, but the domain name is much easier to remember. Without DNS, you would need to enter an IP address any time you wanted to access a resource on the Internet
Domain Names
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You can tell quite a bit about a web site and the company or organization that owns it by looking at the domain name
A typical domain name consists of three labels separated by periods or dots:
Server Name Identifies the name of the web server Registered Domain
Name Identifies the organization that owns the domain name. Each domain name on theInternet is unique Toplevel Domain Identifies the category of the registered domain name
The toplevel domain indicates the type of site you are looking at. The original toplevel domains are:
.com Indicates commercial or company sites. Most com web sites sell a service or product, and usually include an online store
.net Another type of commercial web site. These sites are usually hosted on a network managed by an Internet Service Provider (ISP)
.edu Represents an education site created to share information about an academic institution, its curriculum, and other activities. This category may also be associated with research organizations
PRINTED BY:
tuan.lm@iigvietnam.com Printing
is for personal, private use only No part of this book may be
reproduced or
transmitted without publisher's prior permission Violators will be
www.ccilearning.com www.google.com