Transcript Chapter 25 The Internet

Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Third Edition
The Internet
Chapter 25
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Overview
Third Edition
• In this chapter, you will learn how to
– Explain how the Internet works
– Connect to the Internet
– Use Internet software tools
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Internet Tiers
Third Edition
• Tier 1 (main tier)
– Seven to twelve companies
– Own long-distance, high-speed fiber-optic networks
called backbones
– Interconnect at network access points (NAPs) in
major cities
across the
globe
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Internet Tiers (continued)
Third Edition
• Tier 2
– Smaller regional networks
– Larger ISPs that provide Internet access are often
Tier 2 providers
• Tier 3
– Even more regional networks
• Built-in redundancy
– Decentralized
– Can easily adapt to
failures on network
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
TCP/IP: Language of the Internet
Third Edition
• TCP/IP is the common language of
the Internet
– Suite of protocols
– Many services—such as HTTP—plus the capability
to create new services
• This vast routed network, running
TCP/IP is the Internet
• How do we tap into it?
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Internet Service Providers
Third Edition
• Internet service providers (ISPs) gain
access to the Internet from leased Tier 1
and Tier 2 connections
• Users gain access to
the Internet by leasing
connections from ISPs
• ISPs come in many
sizes
– National companies
– Local shops
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Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Connection Concepts
Third Edition
• Connecting to an ISP requires
– Hardware for connectivity
• Modem and working phone line
• DSL or cable modem
• Some other high-speed connection
– Software (protocols)
• Governs the connection and data flow
– Software (services)
• E-mail, browsing
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Many Ways to Connect
Third Edition
• Dial-up
– Analog
– ISDN
• Dedicated
– DSL
– Cable
– Fiber
– LAN
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• Wireless
– Wi-Fi
– Cellular
• Satellite
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Dial-up Requires a Modem
Third Edition
• The term modem is an abbreviation for
modulator/demodulator
– Enables computers to communicate with each other
via standard telephone lines
– Converts analog signals into digital signals
– Converts digital signals
into analog signals
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Modems
Third Edition
• A modem uses serial communication
– Transmits data as a series of individual 1s and 0s
• Universal asynchronous
receiver/transmitter
(UART)
– Converts serial into 8-bit parallel data
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Baud Rate
Third Edition
• Baud rate is the basic cycle of time that a
modem uses as its carrier frequency
– Maximum baud rate of a phone line is 2400 baud
• The modem speed is measured in bits
per second (bps)
– Modems can pack multiple bits into a single baud
– 14 bits × 2400 baud = speed of 33.6 Kbps
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Communication Standards
Third Edition
• Modern modem standards are referred to
as V standards
– Set by the International Telecommunication
Union—Telecommunications Standardization Sector
(ITU-T)
– Both standards offer download speeds of just under
56 Kbps
• V.90 upload speeds of up 33.6 Kbps
• V.92 upload speeds of up to 48 Kbps
• Rarely get download speeds greater than
48 Kbps
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Modem Connections
Third Edition
• Modems connect to the PC in one of
two ways
– Internal modems connect to a
PCI or PCI Express expansion slot
– External modems connect through
a serial port or USB port
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Dial-up Networking
Third Edition
• Dial-up networking
– Uses information from your ISP
• The dial-up phone number, user name, password, and other
special configuration parameters
– Configured in Network
and Internet Connections
option in Windows XP
• Select Set up or change
your Internet connection
and use the wizard
– Configured in the Network
and Sharing Center in
Vista
• Set up a connection or network
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Dial-up Networking (continued)
Third Edition
• Uses PPP protocol
– Point-to-point protocol (PPP)
– Streaming protocol developed especially for dial-up
Internet access
• Most dial-up errors are user errors
– Turn the volume up and verify the connection
– Listen for a dial tone
– Listen for “modem talk” instead of a person
answering the phone
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
ISDN
Third Edition
• Integrated Services Digital Network (ISDN)
– Phone companies have upgraded their network
infrastructures to all digital lines (except for the
line from your phone to the central office)
– ISDN goes fully digital
– Uses channels
• B (Bearer) used for data and voice at 64 Kbps
• D (Delta) used for setup and configuration information at
16 Kbps
• Basic Rate Interface (BRI)
– Most common setup
– Two B (total of 128 Kbps) and one D channel
– ISDN uses terminal adapters rather than modems
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
DSL
Third Edition
• Digital subscriber line (DSL)
– Uses a regular phone line but special equipment at
both ends
– Much faster than dial-up
• Upload: 128-384 Kbps
• Download: 2-6 Mbps or greater
– Installation requires a NIC and DSL
receiver (often called a DSL modem)
– Must be within 18,000 feet
from the closest main
phone service switching
center
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Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Cable
Third Edition
• Uses cable TV connections
– Connect the RG-6 or RG-59 coaxial cable to a cable
modem
– Connect modem to a NIC in the PC with UTP cable
• Very fast speeds—often much faster than
DSL (20+ Mbps download)
• Bandwidth is shared with other users,
which can affect performance
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Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Fiber
Third Edition
• FiOS from Verizon
– Fiber direct to the home
– Download speeds vary from 5 Mbps down/2 Mbps
up to 50 Mbps down/20 Mbps up
– Average is 15 Mbps down/5 Mbps up
• U-verse from AT&T
– Mix of fiber and local copper at the house
– Average download of 3-6 Mbps down/1 Mbps up,
with 24 Mbps down possible
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Other Internet Connections
Third Edition
• LANs
– Most companies connect their network to the
Internet through an ISP
– Users connect through the LAN
• Wireless
– Wireless connections require access via wired
network
– If wired network has access, wireless devices can
use this wired network via a WAP
• Satellite
– Uploads previously done through modem
– Initial connections still must be made through a
modem
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Internet Connection Sharing
Third Edition
• Internet connection sharing (ICS)
– Allows one computer to share a single Internet
connection with multiple devices
– Available since Windows 98 SE
– Requires a LAN between
the devices
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Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Hardware Connection Sharing
Third Edition
• SOHO routers like this WRT54G are very
popular hardware connections between
your network and the ISP
• Provide hardware
firewall protection
• Built-in WAP
• Built-in switch
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Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Network Address Translation (NAT)
Third Edition
• NAT enables multiple devices to share a
single Internet address
• Most ISPs provide a single Internet
address
– Without routers that supported NAT, you would
have to purchase separate IP addresses for every
device that needed Internet access
– Alternatively you could use your own IP addresses,
but only if you didn’t connect to the Internet
• NAT = GOOD!
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Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Basic Router Configuration
Third Edition
• All routers have an administrative user
name/password that enables you to
configure the router
• Change from the default
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Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
DHCP or Not DHCP
Third Edition
• All home routers are DHCP servers by
default
• You should only have one DHCP server
• Disable DHCP if you already have a DHCP
server
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Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Set the WAN Address
Third Edition
• WAN addresses can be static or dynamic
• If you’re allocated a static IP address,
update your WAN connection per ISP
instruction
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Updating Firmware
Third Edition
• SOHO routers often have firmware
updates – check with the manufacturer
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Internet Software Tools
Third Edition
• Once you’ve made the connection to the
Internet, you can now use the thousands
of Internet applications
• CompTIA wants you to know about the
following applications
–
–
–
–
–
–
World Wide Web (HTTP and HTTPS)
E-mail (POP and SMTP)
Newsgroups
FTP
Telnet
VoIP
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
TCP/IP Ports
Third Edition
• Every Internet application is assigned
one or more TCP/IP port number(s)
– 1-65536
• The first 1024 port numbers are reserved
for the most popular and common
applications
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
World Wide Web
Third Edition
• The World Wide Web (Web) provides a
graphical face for the Internet
– Web servers house Web sites
– Web browsers access the files on Web servers
• Web browsers are highly configurable
– A proxy server enables multiple connections to the
Internet to go through one protected PC
– Similar to ICS, but more sophisticated
• Typically used in corporate connections
• Uses Layer 7 – browsers communicate directly with the
proxy server software when desiring a Web site
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Proxy Server
Third Edition
• A proxy server is a device
or software that acts as
an intermediary between
Internet servers and
clients
• Commonly used to filter
Internet access
• Clients must be
configured to use a
proxy server
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
World Wide Web
Third Edition
• Security and scripts
– Active programs and scripts such
as Java and Active Server Pages
• Can be useful and powerful
• Can be malicious
– Internet Explorer has configurable
options
• Tools | Internet Options|
Security tab lets you set
security levels
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
HTTP vs. HTTPS
Third Edition
• HTTP provides no encryption
• HTTP over Secure Sockets Layer (HTTPS)
– Provides encryption
– Use when submitting personal information such as
credit card numbers, phone numbers, etc.
– Verify HTTPS is being used two ways
• Lock icon
• HTTPS appears in address bar
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
E-mail
Third Edition
• Popular e-mail programs
– Microsoft Outlook
– Mozilla Thunderbird
• E-mail protocols
– Post Office Protocol version 3 (POP3)
• Used for receiving e-mail
– Internet Message Access Protocol (IMAP)
• Used for receiving mail, but with more features than
POP3
– Simple Mail Transfer Protocol (SMTP)
• Used for sending e-mail
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
E-mail (continued)
Third Edition
• Configuring e-mail
– Can use name or IP
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Web Mail
Third Edition
• Available anywhere you have Internet
access
• Free, but requires some sort of
connection
• Most services offer lots of storage,
searchable messages, flagging of
messages for follow-up, etc.
• Most popular
– Gmail
– Hotmail
– Yahoo! Mail
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
E-mail Security
Third Edition
• Digital signatures confirm identity of
sender of e-mail
• Concepts are simple, implementations
not so much
– Requires that you get a certificate from an issuing
authority (same folks who create certificates for
secure e-commerce)
• Try Thawte’s Personal e-mail certificates
• http://www.thawte.com/resources/personal-emailcertificates/index.html
– Then must add to e-mail application
• Easy in Outlook, barely possible in Web mail
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Newsgroups
Third Edition
• Use a newsreader program to access
newsgroups
– Outlook Express was common newsreader (free)
– News servers run Network News Transfer Protocol
(NNTP)
– Get NNTP address from ISP
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
FTP
Third Edition
• File Transfer Protocol (FTP)
– Used to share files
– Address usually ftp.[whatever].com
– Requires an FTP server on one end and an FTP client on
the other
• WS_FTP is a popular client
• Some Web browsers
also support FTP
– Public FTP servers
allow anonymous
login
• User Name: Anonymous
• Password: e-mail address
• Sends user name and
password in clear text
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Telnet and SSH
Third Edition
• Text-based terminal emulation programs
for controlling a remote computer
• They look the same but
– Telnet is unencrypted
– SSH is encrypted
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
VoIP
Third Edition
• Voice over IP (VoIP)
– Enables voice calls over the network
– Works with any type of high-speed connection
• DSL, cable, satellite, etc.
– VoIP is a collection of protocols
• Not a single protocol
– Vendors
• Skype
• Vonage
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Terminal Emulation
Third Edition
• Enables access to other computers as if
you were there
• Windows Remote Desktop
• University of Cambridge’s VNC
– Free and totally
cross-platform
– Can run and control
Windows from a
Macintosh system and
vice versa
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Terminal Emulation (continued)
Third Edition
• Remote Desktop
– Microsoft’s
implementation
– Free and built into
system
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
• Remote Assistance
– End user requests help
– Helper can take control
of desktop
• If permission granted
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Remote Desktop
Third Edition
• Remote Desktop enables you to access
computers over the network
• Excellent tool for managing headless
servers
• Here’s how to get there
– Start | Run or Start Search | mstsc
– Start | All Programs | Accessories |
Communications | Remote Desktop
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Virtual Private Networks (VPN)
Third Edition
• Allows you to connect to a private
network via the Internet
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Beyond A+
Third Edition
• Online gaming
– World of Warcraft (WoW)
– Counter-Strike
• Chat
– Internet
Relay
Chat
(IRC)
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Beyond A+
Third Edition
• File sharing
– Allows users to share files with other users
– Users can access any shared files (such as MP3s)
on any computer anywhere on the Internet
– Napster and Kazaa are file-sharing programs
• Music industry trying to
stop file sharing
• BitTorrent protocol to
counter music industry
– Also used for Linux
distributions
– µTorrent is one program
using BitTorrent protocol
© 2010 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA
A+® Guide to
Managing and
Troubleshooting PCs
Third Edition
© 2010 The McGraw-Hill Companies, Inc. All rights reserved