Transcript Chapter 7

Chapter 7
Connecting to the Internet
Getting Started
• In this Chapter, you will learn:
− What is the Internet
− Options for Internet service
− What is an IP address
− How to avoid online intrusions
− About Hardware: Wired and wireless network
devices
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What is the Internet?
• The Internet is the largest computer network
– A computer network is a collection of computers and
devices linked to share data, hardware, and software
– Data is exchanged using TCP/IP, which is a protocol that
divides information into packets of data
– The Internet backbone is a network of high-capacity
communication links maintained and accessed by:
• Network service providers (NSPs)
• Network access points (NAPs)
• Internet service providers (ISPs)
– The computer you use to access the Internet is the client
computer. Typically you will connect to the Internet using
a modem
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What is the Internet?
Diagram of Internet Connection
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What are the options for Internet
service?
• Internet services vary in cost, speed, and reliability
– Costs range from U.S. $10 to $100/month
– Speeds range from 56 Kbps to 6 Mbps
– Connection types
• Symmetrical connections provide the same downstream and
upstream data speeds
• Asymmetrical connections are the most popular and have faster
downstream data speeds
– Losing your Internet connection is frustrating
• Cable connections are very reliable
• Wireless connections are not as reliable but are convenient when
you are on the go
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What are the options for Internet
service?
• Cable Internet service
– Uses same infrastructure as cable television
– Offers fastest access speeds
– Uses a cable modem
• DSL (digital subscriber line)
– Runs over standard phone lines
– Offers one of the fastest connections available to
individuals
• Dial-up Internet service
– Uses a voiceband modem and telephone lines
– Typically less than $10/month
– Access speed is slow
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What are the options for Internet
service?
• Satellite Internet service
– Distributes access via a personal satellite dish
– In rural areas may be only choice other than dial-up
– Susceptible to bad weather and slow signal time
• WiMax
– Newest technology, limited availability
– Transmits data to nearby communication tower
• Mobile broadband
– Access to the Internet is through high-speed cellular
technology
– Used for PDAs, smartphones, notebooks
– Can have slower speeds, dropped connections
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What’s an IP address?
• Every device has an IP address that identifies it
– IP addresses such as 204.127.129.1 are divided by periods into four
segments called octets
– Static IP addresses are permanently assigned and are used by ISPs and
Web sites that need to be found at the same address
– Dynamic IP address are used by most other users and are temporarily
assigned by your ISP
• Dial-up users get a new IP every time
• DSL/Cable users have an always-on connection with the IP address
remaining the same for days, weeks, or months
• Through geolocation, your IP address indicates the general
region of the world where your computer resides
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What’s an IP address?
You can check your IP address
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How do I avoid online intrusions?
• An intrusion is any access to data or programs by
hackers, criminals, or other unauthorized persons
– Access can be gained through an open port. A port is any
pathway of data in or out of a computer
– Port scanning software looks for unprotected computers
and can attack an unprotected computer within 9 minutes
– To protect your computer:
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Use online tools to check for open ports
Shut down your computer when not in use
Download operating system security patches
Use personal firewall software
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Hardware: Wired and wireless
network devices
• The Internet connects many smaller networks
sometimes called local area networks (LANs)
– Connect computers, printers and scanners at school,
work, and home
– Most popular technologies are Ethernet and Wi-Fi
• Ethernet
• Wired network technology
• Most computers include Ethernet port
• Connections are fast, inexpensive, reliable, and fairly
secure
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Hardware: Wired and wireless
network devices
Ethernet port
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Hardware: Wired and wireless
network devices
• Wi-Fi
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Wireless networking technology uses radio waves
Equipment widely available and fairly affordable
Main advantage is mobility
Security provided by Wireless encryption
• Router is centerpiece of LANs
• Support both wired and wireless devices
• Controls flow of data
• Use as a security device to assign private IP addresses
through network address translation
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Hardware: Wired and wireless
network devices
Diagram of LAN connected to router
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Do we need anonymous
digital cash?
• What do you think?
– Have you ever made a purchase from the Internet
using a credit card?
– Do you think that most people believe that using a
credit card in a restaurant is safer than using a
credit card on the Internet?
– Do you think that anonymous digital cash is a good
idea?
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Chapter Summary
• You should now be able to:
− Understand what is the Internet
− Choose an Internet service option
− Understand IP addresses
− Avoid online intrusions
− Understand wired and wireless network
devices
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