Technology in ActionTechnology in Action

Chapter 7

Networking and Security:Connecting Computers and Keeping Them Safe from

Hackers and Viruses

Chapter Seven ObjectivesChapter Seven Objectives• Networks

– Client/Server– Main components– Common types

• Hackers and harm

• Firewall

• Viruses

• Protection

Networking FundamentalsNetworking Fundamentals

• Definition

• Benefits

• Internet share

Network ArchitecturesNetwork Architectures

• Nodes

• Peer-to-peer

• Client/Server

Networks and DistanceNetworks and Distance

• LAN

• WAN

Data Transmission MediaData Transmission Media

• Twisted pair

• Coaxial

• Fiber optic

Data Navigation DevicesData Navigation Devices

• Packets

• Routers

• Hubs

Networking SoftwareNetworking SoftwareFor peer-to-peer

For client/server

Peer-to-Peer Network TypesPeer-to-Peer Network Types

• Power line

• Phone line

• Ethernet

• Wireless

Power Line NetworksPower Line Networks

• Uses house wiring– Max at 14 Mbps

• Power line network adapter– USB or Ethernet

• Plug and play– Software

• Routers and hubs • Uses phone lines

and jacks– Sharing with

phones– Max at 10 Mbps

• HPNA adapter or USB

• Routers and hubs

Ethernet Networks Ethernet Networks

• Most efficient– Usual speed at 100 Mbps

• Use unshielded twisted pair cable (UTP)

• Use routers and hubs

• Use NICS (network interface cards)

Ethernet CablingEthernet Cabling

• Installation, distance

• UTP categories

Cable CategoryMaximum Data Transfer Rate

Category 5 (CAT 5) 100 Mbps

Category 5E (CAT 5E) 200 Mbps

Category 6 (CAT 6) 1000 Mbps (1 Gbps)

Fig 7.11

Ethernet ArchitectureEthernet Architecture

• Hubs

• Routers– DSL/cable routers

• Internet

Wireless NetworksWireless Networks

• Radio waves, not cabling

• Wi-Fi – Several IEEE standards

• Wireless network adapter

• Transceiver

Wireless ConsiderationsWireless Considerations

• Range, signal degradation

• Node positions– Wireless access point

• Internet connection– Wireless DSL/cable routers

Peer-to-Peer QuestionsPeer-to-Peer Questions

• Existing wiring?

• Wireless also?

• How fast?

• Budget?

Comparing Home Networks Comparing Home Networks

Factors: Power Line

Phone Line

Ethernet

Wireless

Maximum data transfer rate (throughput)

14 Mbps

10 Mbps

100 to 1000 Mbps

11 to 54 Mbps

Approximate cost to network two computers (adapters and wiring only)

$160 $120 $135 $225

Additional cost for adding Internet connection sharing

$80 $120 $0 $40

Approximate cost to add a computer to network

$80 $60 $40 $60

Configuring Home Network Configuring Home Network SoftwareSoftware

• With XP

• With OS mix

• Without XP

Computer SafetyComputer Safety

• Cybercrime

• Cybercriminals

Computer Threats: Hackers Computer Threats: Hackers

• White hat

• Black hat

• Script kiddies

Why Hack?Credit cards

Packet sniffer

Identity theft

Safety TipsSafety Tips

• Hide passwords, pins

• Personal info

• Passwords:– Numbers and letters

– Obscure letter combinations

• FTC Identity Theft

Hacker ActivitiesHacker Activities• Trojan horses

– Far-reaching damage

– Back-door programs

• Denial of service

• Distributed DOS• Hacker access:

– Directly– Via logical ports

Firewall ProtectionFirewall Protection

Software– Easy, port protection

Hardware

Firewalls…Firewalls…

• Block ports

• Hide network address

• Use packet-filtering

• Use NAT

Computer-At-Risk TestingComputer-At-Risk Testing

• Free test fromGibson Research Corporation

Computer VirusesComputer Viruses

• Definition

• Kinds of damage

• Virus sources

Computer Viruses: TypesComputer Viruses: Types

• Grouped by behavior and method of transmission– Boot sector

– Logic bombs

– Worms

– Script and macro

– Trojan Horses

How Viruses Avoid DetectionHow Viruses Avoid Detection

• Polymorphic

• Multi-partite

• Stealth

Antivirus SoftwareAntivirus Software

• Norton

Antivirus SoftwareAntivirus Software

• Virus signatures

• Known viruses

• “Signature” updates

Other Security MeasuresOther Security Measures

• Update OS– System updates

– Security patches

Networking and Security Networking and Security Topic SummaryTopic Summary

• What is a network– Advantages

• Difference between a client/server network

and a peer-to-peer (P2P)

• Main network components

• Common home networks

• Power line networks

• Phone line networks

Networking and Security Networking and Security Topic SummaryTopic Summary

• Ethernet networks

• Wireless networks

• How hackers attack– Harm

• Firewall– How does it keep a computer safe

• Viruses

• Protection