The Internet is a global system of interconnected computer networks that use the Internet protocol suite to link devices worldwide. It was created by the US Department of Defense in the 1960s but has since grown to be a public, self-sustaining facility. An intranet is a private network that uses Internet protocols to securely share part of a company's information or operations, while an extranet extends an intranet to external users for specific limited collaboration. Internet service providers give customers access to the Internet for a monthly fee. Common types of connections include broadband, cable, dial-up, DSL, fiber, and wireless.

1. UNIT -07
VII: Internet Basics

2. INTERNET
The Internet is a worldwide, publicly accessible series of
interconnected computer networks that transmit data.
 It is a "network of networks" that consists of millions of
smaller domestic, academic, business, and government
networks, which together carry various information and
services, such as electronic mail, online chat, file transfer,
and the interlinked Web pages and other documents of the
World Wide Web.

4. No one owns it
It has no formal management organization.
 It was conceived by the Advanced Research
Projects Agency (ARPA) of the U.S. government in
1969 and was first known as the ARPANet.

5. The internet is the most cost-effective communications method in the world,
in which the following services are instantly available:
 Email
 Web-enabled audio/video conferencing services
 Online movies and gaming
 Data transfer/file-sharing, often through File Transfer Protocol (FTP)
 Instant messaging
 Internet forums
 Social networking
 Online shopping
 Financial services

6. Intranet
 An intranet is a secure and private enterprise network that
shares data or application resources via Internet Protocol (IP).
An Intranet differs from the internet, which is a public network.
 the term can also be defined as a secure local network where
employees collaborate, find company information, create
content, and manage tasks and events. It is designed for
internal communications. It is a multifunctional tool that works
as a website, communications channel, and collaboration
platform.

7. An intranet includes a wide range of service such as
the following:
File sharing and document management
Personalised news feed
Automated business processes such as online forms
Project workspaces
Employee directories, including skills and contact
information
Digital workplace

8. An intranet uses TCP/IP, HTTP, and other
Internet protocols and in general looks like
a private version of the Internet.

9. Advantages of intranet:
 Help users to locate and view information faster and use
applications relevant to their roles and responsibilities, which
enable team work.
 Allow organizations to distribute information to employees on
an as-needed basis, employees may link to relevant
information at their convenience.
 Allow Intranet developers to write applications that only have
to work on one browser (no cross-browser compatibility
issues).
 Help to promote common corporate culture as every user has
the ability to view the same information within the Intranet

10. extranet
An extranet is a private network that uses
Internet technology and the public
telecommunication system to securely share
part of a business's information or operations
with suppliers, vendors, partners, customers,
or other businesses.

11. An extranet requires security and privacy.
These can include firewall server
management, the issuance and use of digital
certificates or similar means of user
authentication, encryption of messages, and
the use of virtual private networks (VPNs)
that tunnel through the public network.

12. Companies can use an extranet to:
Exchange large volumes of data using Electronic
Data Interchange (EDI)
Share product catalogs exclusively with wholesalers
or those "in the trade"
Collaborate with other companies on joint
development efforts
Jointly develop and use training programs with other
companies

13. Advantages of extranets include:
 The ability to exchange large volumes of data using electronic
data interchange
 Sharing product data or catalogs with business partners
 Joint company collaboration and training
 Sharing services such as online banking applications among
affiliated banks

14. Basis Internet Intranet
Operation Operated by linked set of
billions of computer servers
worldwide.
Controlled by a single server.
Access Unlimited; Any person
connected to internet can use it.
Limited; Restricted to
employees of the organization.
Users Different kind if users with
different needs.
Similar as all are employees.
Use/ Purpose Used to find out information
about your products
Used for everyday work inside
the company
Speed Slower as more number of
users.
Fast, as few numbers of users.
Compatibility Different type of web browsers
and operating systems are used
which may create compatibility
problems.
Same operating system and
web browser is used which do
not cause any cross platform
compatibility problems.

15. Internet Intranet Extranet
A global network which is
available to anyone who wants
to access information
An intranet is unique to an
organization or group of people
who work together at a place
Extranet is for individuals
or group of personnel who
want to send private
information
PRIVACY
Public Private intermediately Extremely Private
DEPENDENCY
Independent
Independent yet dependent
on internet
Dependent on internet and
intranet
FIREWALL
No Can have Yes

16. What Is IIS?
Internet Information Services
 IIS is a web server that runs on the Microsoft .NET platform on the
Windows OS.
 What Is a Web Server?
 A web server is a process for hosting web applications. The web
server allows an application to process messages that arrive through
specific TCP ports (by default). For example, the default port for HTTP
traffic is 80, and the one for HTTPS is 443.
 Versions of IIS
 IIS has evolved along with Microsoft Windows. Early versions of IIS arrived
with Windows NT. IIS 1.0 appeared with Windows NT 3.51, (Windows Server 2012
R2 uses IIS 8.5). And IIS 10 arrived with Windows Server 2016 and Windows 10.

17. How does IIS handle web requests?
The two main process models for web servers are to
either handle all requests on a single thread, or to spawn
a new thread for each request.
Web servers typically handle requests using a request-
response pattern. The client sends a request and receives
a response if all goes well. HTTP protocol is the universal
choice when communicating between a client and web
server over the internet.

18. Features of IIS
 IIS is rich with features. Most commonly, IIS is used to host ASP.NET
web applications and static websites. It can also be used as an FTP
server, host WCF (Windows Communication Foundation ) services, and be
extended to host web applications built on other platforms such as
PHP.
 There are built-in authentication options such as Basic, ASP.NET,
and Windows auth. The latter is useful if you have a Windows Active
Directory environment—users can be automatically signed into web
applications using their domain account. Other built-in security
features include TLS certificate management and binding for
enabling HTTPS and SFTP on your sites.

19. WWW
 The World Wide Web (abbreviated as WWW or W3, and commonly
known as the Web) is a system of interlinked hypertext documents
accessed via the Internet. With a web browser, one can view web
pages that may contain text, images, videos, and other multimedia
and navigate between them via hyperlinks.
 It was initiated at CERN (the European Organization for Nuclear
Research)by Tim Berners-Lee.

20. Web Page
Web Page
A document on the World Wide Web, consisting of
an HTML/PHP/ASPX file and any related files for
scripts and graphics, and often hyperlinked to other
documents on the Web. The content of web pages is
normally accessed by using a browser.

21. Web Sites
 Information on the Web is displayed in pages. These pages are written in a
standard language called HTML (Hyper Text Markup Language) which describes
how the information should be displayed. Pages also include hypertext links which
allow users to jump to other related information. Hypertext is usually underlined
and in a different color and can include individual words, sentences, or even
graphics. A Web site is a collection of related Web pages with a common Web
address.

22. Client
Client is a computer which request for resources
from the server.
Client machine run some application program (like
internet explorer) and request for data/information.
Server
A server is a computer equipped with server
software, which provide specific kind of service to
client software running on other computer.

23. TYPES OF WEB DOCUMENTS
 Static Document
 Static documents are fixed-content documents that are
created and stored in a server. In this context, even a video is
a static Web page because it is just a file.

 The client can get only a copy of the document. The content
can only be changed by the Web developer and all the users
accessing the webpage get a copy of the same document.

24. Dynamic Document
 A dynamic document is created by a Web server whenever a
browser requests the document. These web pages do not
exist in a predefined format and are created by a web server
only when a client program requests for it.
 When a request arrives, the Web server runs an application
program or a script that creates the dynamic document

25. Search Engines
 A search engine is software, typically accessed on the Internet, that
searches a database of information according to the user's query.
 Today, there are many different search engines available on the Internet,
each with their own abilities and features. The first search engine ever
developed is considered Archie, which was used to search for FTP files
and the first text-based search engine is considered Veronica. Today, the
most popular and well-known search engine is Google. Other popular
search engines include AOL, Ask.com, Baidu, Bing, and Yahoo.

26. How a search engine works
 High-level architecture of a standard Web crawler. A search engine operates in the following
order:
 Web crawling
 Indexing
 Searching

27. the source of all search
engine data is a spider or
crawler, which automatically
visits pages and indexes
their contents.

28.  Web search engines work by storing information about many
web pages. Firstly, a search engine sends out a spider to
fetch as many documents as possible. Then another program
called as an indexer reads these documents and creates an
index based on the words contained in each document. The
purpose of an index is to allow information to be found as
quickly as possible.

29. When you query a search engine to locate information, you
are actually searching through the index that the search
engine has created and you do not search the web.
Most search engines employ methods to rank the results
to provide the "best" results first. How a search engine
decides which pages are the best matches, and what order
the results should be shown in, varies widely from one
engine to another. The methods also change over time as
Internet usage changes and new techniques evolve.

30.  Searching techniques

 Natural Language Searching - A Search Like Google
 Google has made most of us comfortable with Natural Language searching. It
takes the words you type into the box and searches for them using the Boolean
operator .
 The most commonly used operators are the words AND, OR, and NOT.

31. Phrase Search
 Surround a group of words with double quotes tells the search engine to
only retrieve documents in which those words appear side by side.
 E.g. ―Global Warming‖
 Plural forms, capital letters and alternate spellings
 Truncation
 Allows you to search at one time for words with similar endings – any one of which
could be relevant to the topic librar* psycholog* librarian psychology librarians
psychologist library psychologists libraries psychological
 librarianship

32. Wildcards
 Allows you to search for possible variations (often spellings) within words
wom*n woman
 women
 Symbols for indicating wildcards vary.
 Fewer databases support wildcards than support truncation.

 Requiring or Excluding Words
 + requires that all items in a list of search results contain certain words or
phrases
 “water rights” +texas cloning +legality
 - requires that none of the items in a list of results contains the excluded
word or phrase dolphins -football
 “lord of the rings” -movie -film

33. Internet Service Providers(ISP)
 An Internet service provider (ISP) is a company that provides access to the Internet.
Access ISPs directly connect customers to the Internet using copper wires, wireless or
fiber-optic connections. For a monthly fee, the service provider usually provides a software
package, username, password and access phone number.
 Typical home user connectivity
 Broadband wireless access
 Cable Internet
 Dial-up
 DSL
 FTTH
 Wi-Fi

34. Type of ISP Connections
Dial-up
 Dial-up ISP services, transfer data between your computer and the web
using a conventional phone line. Dial-up is being phased out because of its
slow speed, but many still rely on it because of its low cost, universal
availability and lack of specialized equipment required.
 DSL ( upto 8 Mbps)
 Digital subscriber line (DSL) is an advanced version of the dial-up Internet
access method. In contrast to dial-up, DSL uses high frequency to execute
a connection over the local telephone network. This allows the Internet and
the phone connections to be run on one and the same telephone line.

35. Wi-Fi Internet
 Wi-Fi (from Wireless Fidelity) has become one of the most widely distributed
Internet access methods, with the growing usage of portable computers and
Internet enabled mobile devices, such as smart phones, PDAs, etc.
 leased line :
 A leased line is a dedicated communication channel that interconnects two
or more sites. This is a service contract between a customer and a
provider. It acts as a dedicated tunnel from one point to the other where
data can continuously flow for a fixed monthly fee or rent, hence the name.
Leased lines are used for Internet, data and even telephone services.
They are typically run on fiber optic cables to provide large bandwidth and
speed.

36.  A leased line is not really a dedicated physical connection, but
a reserved circuit between two designated points that is open
at all times.
 Cable connection: Cable provides an internet connection
through a cable modem and operates over cable TV
lines. There are different speeds depending on if you are
uploading data transmissions or downloading. Since the coax
cable provides a much greater bandwidth over dial-up or DSL
telephone lines, you can get faster access.

38. Server based LAN and peer to peer LAN
 a peer-to-peer network has no central server. Each
workstation on the network shares its files equally with the
others. There’s no central storage or authentication of users.
 Server based LAN -there are separate dedicated servers and
clients in a client/server network. Through client workstations,
users can access most files, which are generally stored on
the server. The server will determine which users can access
the files on the network.

39.  The concept behind peer-to-peer networking is to share files
and printers as inexpensively as possible; therefore, there’s
no main server on the network. Instead, each client functions
both as a client and as a server simultaneously. Since users
are allowed to control access to the resources on their own
computers, however, security becomes very risky in a peer-to-
peer environment
 centralized security databases that control access to shared
resources on servers. In the world of Windows, the server
usually runs NetWare, Windows 20012 Server products.

40. BASIS FOR COMAPAISON CLIENT-SERVER PEER-TO-PEER
Basic There is a specific server and
specific clients connected to the
server.
Clients and server are not
distinguished; each node act as
client and server.
Service The client request for service and
server respond with the service.
Each node can request for
services and can also provide the
services.

41. Data The data is stored in a
centralized server.
Each peer has its own data.
Server When several clients request for
the services simultaneously, a
server can get bottlenecked.
As the services are provided by
several servers distributed in
the peer-to-peer system, a
server in not bottlenecked.
Expense The client-server are expensive
to implement.
Peer-to-peer are less expensive
to implement.

42. e-mail
Short for electronic mail, or email is information
stored on a computer that is exchanged between two
users over telecommunications. More plainly, e-mail is
a message that may contain text, files, images, or
other attachments sent through a network to a
specified individual or group of individuals.
The first e-mail was sent by Ray Tomlinson in 1971.

43. Advantages of e-mail
 There are many advantages of e-mail and the usage of e-mail versus postal mail.
Some of the main advantages are listed below.
 Free delivery - Sending an e-mail is virtually free, outside the cost of Internet service.
There is no need to buy a postage stamp to send a letter.
 Global delivery - E-mail can be sent to nearly anywhere around the world, to any
country.
 Instant delivery - An e-mail can be instantly sent and received by the recipient over the
Internet.
 File attachment - An e-mail can include one or more file attachments, allowing a
person to send documents, pictures, or other files with an e-mail.
 Long-term storage - E-mails are stored electronically, which allows for storage and
archival over long periods of time.
 Environmentally friendly - Sending an e-mail does not require paper (paperless),
cardboard, or packing tape, conserving paper resources.