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Transcript of The Internet
![Page 1: The Internet](https://reader031.fdocuments.in/reader031/viewer/2022020206/548e06e5b47959686c8b482c/html5/thumbnails/1.jpg)
Using the Internet: Making the Most of the Web’s Resources
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Topics
Internet communications Online annoyances How the Internet works Internet Basics Origin of the Internet Future of the Internet
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Communications through the Net
VOIP Wikis Newsgroups Email Mailing lists Social networking E-commerce
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Voice over Internet Protocol VoIP - The Internet as a means to place phone calls Uses technology similar to e-mail to send voice data
digitally Requires
a microphone an Internet connection A VoIP provider
Services differ Free services require an account on both ends Paid services connect phone to computer Cable and DSL providers offer phone through broadband WiFi IP phones call through Internet hotspots and wireless
networks
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Wikis
A wiki is a Web site that allows anyone to change its content
Wikis provide an excellent source for collaborative writing
Unlike blogs, wikis can be edited for a “common” opinion
Edits can be anonymous or named Be careful of bias in entries “wiki” is a Hawaiian word for “fast” First site with wiki in the name set up in 1995
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Newsgroups
Usenet "News" formed in 1980
Online discussion forums
Post and reply to messages publicly
Need a feed from a news server - most ISPs have one
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fast, convenient, cheap
asynchronous E-mail accounts
Client-based Web-based
Forwarding(image from Wikipedia "How
Email Works")
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Mailing lists
"Listservs" people must subscribe messages sent by email sent only to people who subscribe,
not general public do NOT use the "Reply All" option
unless you mean to!
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Social Networking
MySpace, FaceBook easy, cheap danger of identity theft danger of revealing information
which can be harmful later danger of sexual predators
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E-commerce
buying, selling, advertising, banking look for secure "signed" sites https:// versus http:// check with Better Business before
buying use credit card for purchase
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Online Annoyances
Spam – electronic junk mail Pop-ups – intrusive advertising Cookies – tracking user’s browsing
habits Malware - software that has a
malicious intent - spyware, viruses, Trojans, worms, etc.
Phishing and Hoaxes – Ruses to fool and maybe steal from users
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Spam Junk e-Mail May soon comprise 90%
of email volume Named after a Monty Python sketch Link Antispam practices
Don’t reply to it, even to “unsubscribe”! Use “dummy” addresses – can get free ones Read privacy statement on a site before you
give them your address Spam filters
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Pop-ups
Usually advertising Pop-up
automatically Can also contain
spyware Most browsers can
prevent them Pop-up blockers
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Cookies
Text files stored on client computers when visiting Web sites
Used on return visits to Web sites
Unique ID number Personal information
remembered Privacy risk
Selling information
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Spyware Added as a program
piggybacked with a requested program
Secretly gathers information, usually about surfing habits
Antivirus software doesn’t detect it
Spyware removal programs are required
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Spyware
Very often comes in from file-sharing, P2P sites
Ties up system resources, can modify browser settings, can spawn popups and other ads
Read the EULA for any software you install before you install!
Run Ad-Aware to clean it up
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Phishing and Hoaxes
Phishing is a phony communication from a trusted source
Phishing attempts to scam someone into sending vital information
Hoaxes are attempts to scam people into sending money, or join a chain letter
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Malware
Software that has a malicious intent Spyware is a form of malware Other forms are viruses, worms, and
Trojan horses Designed to render a computer
useless or control it completely
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How the Internet works
Domain Names URLs Navigating the Web
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Domain Names
Easy-to-remember names for Internet servers Ends with an extension that indicates its top-
level domain Every domain name corresponds to a
unique IP address Domain Name System cybersquatting
ICANN coordinates technical management of the Internet’s Domain Name System
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Domain Names
Most specific information on the LEFT
Top Level Domain Names .gov .com .edu .net
Subnets and Sub Domains uky.edu cs.uky.edu www.cs.uky.edu ftp.cs.uky.edu
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Current Top-Level Domains.aero Members of the air transport
industry.biz Businesses.com Can be used by anyone.coop Cooperative associations.edu Degree granting institutions.gov United States government.info Information service providers.mil United States military.museum Museums.name Individuals.net Networking organizations.org Organizations (often nonprofits).pro Credentialed professionals
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Top Level Domains - Country Codes
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URL
Uniform Resource Locator Unique Internet address
Protocol could be http, mailto, ftp, news, …
NOTE difference between http and https
URL http://
Protocol identifies the means of access
www.nytimes.com/
Domain name contains the host and top-level domain
Pages/cartoons/
Path identifies the subdirectories
within the Web site
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Navigating the Web: Web Browsers
Software running locally on your machine
Graphical Enables Web
navigation Popular browsers:
Internet Explorer Firefox Camino (Mac OSX)
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Web Sites
Web site: Collection of related Web pages First page known as Home or Index
page Web pages:
HTML documents Hyperlinks
Related pages
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The Internet and Copyright
All original material on the Net is copyrighted, © or not
Copyright is violated when you get economic benefit from using the material Exception of "academic fair use"
Plagiarism is different from copyright violation – it is presenting someone else's work as your own Credit your sources!
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Search Engines
“Spider” or “Web Crawler” program scans Web pages
Information found is entered in their database
User enters keyword or phrase in search box in browser
Results (hits) are sent to the client software and displayed
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Evaluating Web Sites
Who is the author of the article or Web site sponsor?
What audience is the site geared toward?
Is the site biased? Is the information current? Are links available? Who is hosting? Is it a .gov
site? .edu? .com?
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File-sharing - P2P networks
Files traded from machine to machine - broadband
Majority of files are copyrighted and permission has not been given for the copying
Risks Legal problems Malware in both the software and the
files
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Software Copyrights and Licenses
Different types of software licenses - where the money come from? Commercial software -from sale of licenses Shareware - from registrations and ads Freeware - from advertising and spyware Open source - free labor of volunteers and
donations Public domain - donations from community
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The Internet: The Basics
Protocols IP numbers Clients and servers Connecting to the Internet Origin of the Internet The Internet vs. the Web
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Internet Protocols
TCP and IP serve as the primary protocols responsible for message transmission on the Internet
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Internet Protocol
Messages are divided into small pieces called packets
These are labeled with the IP numbers of the machine they came from and the one they are going to, and a order number ( like 1 of 5)
The protocol says how to route them to get to the destination
Not all packets take the same route!
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IP Addresses
IP addresses are addresses that identify computers on the Internet Static IP address Dynamic IP address
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IP Addresses
IP addresses have the problem in TCP/IP of running out
Internet 2 consortium designing new protocols that fix the problem
Dynamic IP numbers – short term fix
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Client and Server
Client computer: Users connect to the Internet Request data and Web pages
Server computers: Store Web pages and data Return the requested data to the client
Server
Client
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Connecting to the Internet Dial-up connection:
Uses standard telephone line
Least costly connection
Requires a modem Converts analog
to digital and vice versa
Slowest connection speed (56Kbps)
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Broadband Connections
Digital Subscriber Lines Faster than dial-up
Upload (300Kbps – 1.5Mbps) Download (1Mbps – 1.5Mbps)
Requires special DSL modem Symmetrical
or Asymmetrical
DSL modem
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Broadband Connections
Cable: Uses TV coaxial
cable Fast connection
speed (500Kbps – 4Mbps)
Speed depends on number of users
Not available in all areas
Requires a cable modem
Coaxial
cable
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Satellite Connections
Uses a satellite dish and coaxial cable Download speed
500 kbps Upload speed 100
kbps Signal is affected
by location and weather
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Comparing Internet Connection Options
Connection Option
Maximum Upload Data Transfer Rate (approximate)
Maximum Download Data Transfer Rate (approximate)
Dial-Up 56 Kbps 56 Kbps
DSL (ADSL) 300 Kbps 1 Mbps
DSL (SDSL) 1.5 Mbps 1.5 Mbps
Cable 500 Kbps 4 Mbps
Satellite 100 Kbps 500 Kbps
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Choosing an ISP
Factors to consider: Cost Local access numbers Services Offered – email, web page
hosting, news reading Reliability Speed Support and Customer Service
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ISP Infrastructure
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The Origin of the Internet ARPANET:
Advanced Research Projects Agency Network Funded by the U.S. government in the 1960s, lasts until 90's Allowed computers at leading universities and research
organizations to communicate with each other over great distances
First Working Version of the Packet Switching Network
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NSFNet – National Science Foundation Network
Connecting 5 supercomputers and the researchers using them, 1986
commercialization of the Internet - late 80's
NSF stops funding the Net - 1994
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Internet Structure
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The Web
The Web is a part of the Internet distinguished by: common communication protocols TCP/IP and
HTML special links (called hyperlinks)
Web invented in 1989 by Tim Berners-Lee 1993, National Center for Supercomputing
Applications (NSF) releases the Mosaic browser
Developers of Mosaic release Netscape (1994)
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The Internet vs. The Web Internet – part of the system that is primarily
hardware infrastructure (telecommunications, routers, servers, disk drives, etcetera)
Web – part of the system that contains intellectual property in many formats (text files, graphic files, sound files, video files, etc.)
The Internet existed before the WWW interface – people used command line programs
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Future of the Internet
Large Scale Networking (LSN): Research and
development of cutting-edge networking and wireless technologies
Internet2: Project sponsored by
universities, government, and industry to develop new Internet technologies
Internet2 backbone supports transmission speeds of 9.6 Gbps
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Internet Access Security
"always on" is security risk - turn the computer off!
keep OS and anti-virus software up to date
USE firewall software browser security settings for LAN, use NAT - router Network
Address Translation virtual private network (VPN)
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Issue: Free Wi-Fi access
Some people offer wireless access for free to the community
A good point - people who can't afford to pay for it can use it
Broadband providers don't like people giving it away for free
A bad point - can be used for illegal activities