Transcript Lecture_Internet_Intranets_Extranets

Internet-Intranets-Extranets
Pindaro Demertzoglou
Lally School of M&T
How the Internet Started
 The ARPANET, created in 1969, connected
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computers at UCLA, Stanford, University of
Utah, and University of California at Santa
Barbara.
Then, the military liked the idea for
distributed decision centers.
Today, the Internet connects computers all
over the globe and supplies information to
people of all ages and interests.
The Internet is not owned or operated by any
single corporation or government.
The Internet is based on a network of
networks.
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IP Addresses
 Static IP address – permanently assigned IP address
 Dynamic IP address – temporarily assigned
 An IP address is a series of numbers, such as
204.127.129.001
 It is separated into four sections by periods
 Each section’s number cannot exceed 255
Domain Names
 People find it difficult to remember long strings of numbers,
so host computers also have names called domain names
 Domain name – “fully qualified domain name” (FQDN),
usually typed in all lowercase
 Key component of URLs and e-mail addresses
 Lallylab2.mgmt.rpi.edu/mis lallylab2.mgmt.rpi.edu is
the domain name (128.113.9.243)
Registering a Domain Name
 http://www.google.com/a/cpanel/domain/new
 http://www.register.com/
 http://smallbusiness.yahoo.com/domains/
TCP - IP
 Transmission Control Protocol (TCP)
 Breaks messages into packets and specifically into octets (eight
bits) reliably and in the correct order.
 Internet Protocol
 Addresses packets from one computer to another.
Internet Statistics
 World Statistics
 http://www.internetworldstats.com/stats.htm
Language Statistics
 http://www.internetworldstats.com/stats7.htm
Top 20 Countries
 http://www.internetworldstats.com/top20.htm
Internet Protocols
WWW
 List of www browsers
 http://en.wikipedia.org/wiki/List_of_web_browsers
 Web Server Statistics
 http://news.netcraft.com/archives/web_server_survey.html
FTP – File Transfer Protocol
 Basic Facts http://en.wikipedia.org/wiki/File_Transfer_Protocol#Software
 FTP Clients
 http://en.wikipedia.org/wiki/Comparison_of_FTP_clients
Email Servers
 List of email servers
 http://en.wikipedia.org/wiki/Comparison_of_mail_servers
 SMTP – POP protocols
DSL, ISDN, and Dedicated Lines
 DSL is a high-speed, digital, always-on Internet access technology
that runs over standard phone lines.
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Cable Internet Service
 Cable Internet service distributes always-on broadband
Internet access over the same infrastructure that offers cable
television service
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Chapter 6: The Internet
Internet Connections
Internet Security
 Intrusion Attempts
 Securing Ports
 Routers and NAT
 Virtual Private Networks
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Intrusion Attempts
 An intrusion is any access to data or programs by
hackers, criminals, or other unauthorized persons
 Looking for open ports is one of the most common
ways of gaining unauthorized access to a networkbased computer.
 A port is associated with an IP address of the host
computer.
 A web port:
http://lallylab2.mgmt.rpi.edu:80/mis/
 A list of ports:
http://en.wikipedia.org/wiki/List_of_TCP_and_U
DP_port_numbers
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Port Scanners
 Software used by network administrators and hackers to
identify open ports of computers in the network.
 http://www.radmin.com/products/previousversions/ports
canner.php
Intranets
 What is an Intranet
 Technical Advantages
 Business Advantages
 Service Platforms
 Intranets in today’s economy
 Measuring Intranet ROI
What is an Intranet
 It is a private information system
 Built on Internet technologies
 Client-server system architecture
 Based usually on three-tier system
 It is not a telecommunications network
Technical Advantages
 Easy to learn
 Fast to build
 Easy to deploy
 Easy to maintain
 Easy to update
 Easy to personalize
Business Advantages
 Cheaper than deploying traditional systems
 Shrinks distances
 Adds to the company’s business intelligence
Business Advantages
 Can link to other sources of information.
 Adds “time” to a company
 Through document sharing (text, drawings).
 Online collaboration
 Cheaper than deploying traditional systems.
 Shrinks distances.
 Adds to the company’s business intelligence.
Intranet Services Platform
 Mail server
 Web server
 Indexing server
 Transaction server
 DB server
 Data Warehouse server
The role of extranets
 What is an extranet?
 It is an extension of the Intranet.
 It includes entities from the external environment of the
company.