1. © 2008 Prentice-Hall, Inc. 1 Technology in Action 1

2. © 2008 Prentice-Hall, Inc. 2 Technology In Action Chapter 7 Networking and Security: Connecting Computers and Keeping Them Safe from Hackers and Viruses

3. © 2008 Prentice-Hall, Inc. 3 Chapter Topics Networking fundamentalsNetworking fundamentals Network architectureNetwork architecture Network componentsNetwork components Peer-to-peer networksPeer-to-peer networks Computer threatsComputer threats Computer safeguardsComputer safeguards Computer virusesComputer viruses

4. © 2008 Prentice-Hall, Inc. 4 Networking Fundamentals Computer network:Computer network: –Two or more computers connected together Each is a NodeEach is a Node Benefits of a network:Benefits of a network: –Sharing resources –Transferring files

5. © 2008 Prentice-Hall, Inc. 5 Network Architecture Network designs:Network designs: –Individual PC controlled: Peer-to-peer (P2P)Peer-to-peer (P2P) –Centrally controlled: Client/serverClient/server Peer-to-peer Client/ server

6. © 2008 Prentice-Hall, Inc. 6 Peer-to-Peer Networks Nodes communicate with each other:Nodes communicate with each other: –Peers Share peripheral devices:Share peripheral devices: –Printers –Scanners Home and small office networksHome and small office networks

7. © 2008 Prentice-Hall, Inc. 7 Client/Server Networks Client computers:Client computers: –Users Server computers:Server computers: –Provide resources to clients –Central network control InternetInternet –A large, multiserver, multiclient network. multiclient network.

8. © 2008 Prentice-Hall, Inc. 8 LANs and WANs Local area network (LAN):Local area network (LAN): –Nodes are within a small geographic region: HomesHomes SchoolsSchools Small businessesSmall businesses Wide area network (WAN):Wide area network (WAN): –LANs connected over long distances: A few miles to thousands of milesA few miles to thousands of miles Use telecommunications linesUse telecommunications lines

9. © 2008 Prentice-Hall, Inc. 9 Network Components Transmission mediaTransmission media Network adaptersNetwork adapters Navigation devicesNavigation devices Network softwareNetwork software

10. © 2008 Prentice-Hall, Inc. 10 Transmission Media Provides communications channel between nodesProvides communications channel between nodes Forms of media:Forms of media: –Telephone wire: Twisted pairTwisted pair –Coaxial cable –Fiber-optic cable –Radio waves: WirelessWireless Bandwidth:Bandwidth: –Data transfer rate –Throughput

11. © 2008 Prentice-Hall, Inc. 11 Network Adapters Devices connected to or installed in nodes:Devices connected to or installed in nodes: –Network interface cards (NIC) –External network adapter Enable communication between nodesEnable communication between nodes

12. © 2008 Prentice-Hall, Inc. 12 Network Navigation Devices Devices that help make data flow possibleDevices that help make data flow possible Routers:Routers: –Route data between networks Switches:Switches: –Receive data and retransmit it to nodes on the network

13. © 2008 Prentice-Hall, Inc. 13 Networking Software Peer-to-Peer Software:Peer-to-Peer Software: Built into operating systems that support networkingBuilt into operating systems that support networking –Windows –Mac OS Client/Server SoftwareClient/Server Software Network operating system (NOS) softwareNetwork operating system (NOS) software –Windows XP Professional –Windows Server 2003 –Novell Netware –Windows Vista Enterprise

14. © 2008 Prentice-Hall, Inc. 14 Types of Peer-to-Peer Networks Power-linePower-line PhonelinePhoneline EthernetEthernet WirelessWireless

15. © 2008 Prentice-Hall, Inc. 15 Ethernet Networks Ethernet network adapters are used to connect nodesEthernet network adapters are used to connect nodes –NIC card –PC Card –USB adapter Computers are connected to each other using unshielded twisted pair cableComputers are connected to each other using unshielded twisted pair cable RJ-45 Phoneline

16. © 2008 Prentice-Hall, Inc. 16 Ethernet Switches Keep track of data packetsKeep track of data packets Amplify and retransmit signalsAmplify and retransmit signals Keep the network running efficientlyKeep the network running efficiently

17. © 2008 Prentice-Hall, Inc. 17 Ethernet Routers Transfer packets from one network to anotherTransfer packets from one network to another Home Internet routers transfer data from the Internet to the home network.Home Internet routers transfer data from the Internet to the home network. Router

18. © 2008 Prentice-Hall, Inc. 18 Wireless Networks Use radio waves to connect nodesUse radio waves to connect nodes Basically an Ethernet network that uses radio waves instead of wiresBasically an Ethernet network that uses radio waves instead of wires Each node requires a wireless network adapter:Each node requires a wireless network adapter: –Transceiver

19. © 2008 Prentice-Hall, Inc. 19 Power-Line Networks Computers are connected to a house’s electrical wiring to create a networkComputers are connected to a house’s electrical wiring to create a network Power-line network adapter is used to connect nodes to electrical outletsPower-line network adapter is used to connect nodes to electrical outlets

20. © 2008 Prentice-Hall, Inc. 20 Phoneline Networks Computers are connected to a house’s telephone wiring to create a networkComputers are connected to a house’s telephone wiring to create a network Home phoneline network adapter is used to connect nodes to phone jacksHome phoneline network adapter is used to connect nodes to phone jacks

21. © 2008 Prentice-Hall, Inc. 21 Choosing a Peer-to-Peer Network Things to consider:Things to consider: –Existing wiring –Wireless or wired –Speed of the network –Cost of the network Comparing the Major Types of Home Networks Wired Ethernet Wireless 802.11g Wireless Enhanced G Wireless 802.11n Maximum data Transfer rate (bandwidth) 100 Mbps to 1,000 bps (1 gigabit) 54 Mbps108 Mbps100 to 630 bps Relative installation and equipment costs for networking two computers $$$$$$$

22. © 2008 Prentice-Hall, Inc. 22 Configuring Software for a Home Network Windows operating system:Windows operating system: –Windows Vista home versions Network setup wizard Network setup wizard –Wired or wireless –Windows XP: Network setup wizardNetwork setup wizard –Windows ME: Network setup wizardNetwork setup wizard –Windows 98: Configure manuallyConfigure manually –Help has a clear instructions

23. © 2008 Prentice-Hall, Inc. 23 Computer Threats Cybercrimes are criminal acts conducted through the use of computers by cybercriminals.Cybercrimes are criminal acts conducted through the use of computers by cybercriminals.

24. © 2008 Prentice-Hall, Inc. 24 Hackers Anyone who unlawfully accesses a computer systemAnyone who unlawfully accesses a computer system Types of hackers:Types of hackers: –White-hat –Black-hat –Script kiddies

25. © 2008 Prentice-Hall, Inc. 25 What Hackers Do Steal information from computers:Steal information from computers: –Credit card numbers –Bank account numbers Internet packet sniffingInternet packet sniffing Commit identity theftCommit identity theft

26. © 2008 Prentice-Hall, Inc. 26 Denial of Service Attacks Backdoor programsBackdoor programs –Trojan horse –Zombies Denial of service attacksDenial of service attacks

27. © 2008 Prentice-Hall, Inc. 27 How Hackers Gain Access Direct access:Direct access: –Hacking software Indirect access:Indirect access: –Internet connection –Logical ports

28. © 2008 Prentice-Hall, Inc. 28 Computer Safeguards Firewalls Software programs or hardware designed to close logical ports to invadersSoftware programs or hardware designed to close logical ports to invaders –A firewall is built into Windows XP –More robust firewalls are available from other vendors. –Firewalls are critical if you have an always-on broadband connection.

29. © 2008 Prentice-Hall, Inc. 29 Protecting a Wireless Network Wireless network range doesn’t stop at the property line.Wireless network range doesn’t stop at the property line. Default device and network ID settings allow intruders to enter the network.Default device and network ID settings allow intruders to enter the network. Internet bandwidth can be stolenInternet bandwidth can be stolen Computers can be vulnerable to hacker intrusion and takeover.Computers can be vulnerable to hacker intrusion and takeover.

30. © 2008 Prentice-Hall, Inc. 30 Computer Threat - Viruses A program that attaches itself to another program and spreads itself to other computersA program that attaches itself to another program and spreads itself to other computers Viruses are hidden within the code of a host programViruses are hidden within the code of a host program

31. © 2008 Prentice-Hall, Inc. 31 How Does a Computer Catch a Virus Viruses copy themselvesViruses copy themselves Infect a file on your computerInfect a file on your computer Viruses spread by sharing disksViruses spread by sharing disks E-mail attachments are the most likely source of a virusE-mail attachments are the most likely source of a virus

32. © 2008 Prentice-Hall, Inc. 32 What Viruses Do Replicate themselves:Replicate themselves: –Slow down networks Secondary objectives:Secondary objectives: –Annoying messages –Delete files on the hard drive –Change computer settings

33. © 2008 Prentice-Hall, Inc. 33 Types of Viruses Boot-sector viruses:Boot-sector viruses: –Replicate themselves in the boot sector of the hard drive Logic bombs:Logic bombs: –Activate when certain conditions are met Worms:Worms: –Travel between systems through networks

34. © 2008 Prentice-Hall, Inc. 34 Types of Viruses Script viruses:Script viruses: –Hidden on Web pages –Mini programs Macro viruses:Macro viruses: –Attached to documents –Series of commands Encryption virusesEncryption viruses –Search for common data files –Compress files using a complex encryption key –User must pay to get the files unlocked Trojan horses:Trojan horses: –Backdoor programs –Control remote computers

35. © 2008 Prentice-Hall, Inc. 35 Virus Classifications Polymorphic viruses: – –Periodically rewrite themselves to avoid detection Multipartite viruses: – –Infect multiple file types Stealth viruses: – –Erase their code from the hard drive and reside in the active memory

36. © 2008 Prentice-Hall, Inc. 36 Antivirus Software Programs designed to detect viruses:Programs designed to detect viruses: –Scan files looking for virus signatures (unique code) –Provides options for deleting or fixing infected files –Inoculates files against further infection Detect known virusesDetect known viruses Antivirus programs need to be updated frequentlyAntivirus programs need to be updated frequently

37. © 2008 Prentice-Hall, Inc. 37 Chapter 7 Summary Questions What is a network and what are the advantages of setting one up?What is a network and what are the advantages of setting one up?

38. © 2008 Prentice-Hall, Inc. 38 Chapter 7 Summary Questions What is the difference between a client/server network and a peer-to-peer network?What is the difference between a client/server network and a peer-to-peer network?

39. © 2008 Prentice-Hall, Inc. 39 Chapter 7 Summary Questions What are the main components of every network?What are the main components of every network?

40. © 2008 Prentice-Hall, Inc. 40 Chapter 7 Summary Questions What are the most common home networks?What are the most common home networks?

41. © 2008 Prentice-Hall, Inc. 41 Chapter 7 Summary Questions What are power-line networks?What are power-line networks?

42. © 2008 Prentice-Hall, Inc. 42 Chapter 7 Summary Questions What are phoneline networks?What are phoneline networks?

43. © 2008 Prentice-Hall, Inc. 43 Chapter 7 Summary Questions What are Ethernet networks?What are Ethernet networks?

44. © 2008 Prentice-Hall, Inc. 44 Chapter 7 Summary Questions What are wireless networks?What are wireless networks?

45. © 2008 Prentice-Hall, Inc. 45 Chapter 7 Summary Questions How can hackers attack a network and what harm can they cause?How can hackers attack a network and what harm can they cause?

46. © 2008 Prentice-Hall, Inc. 46 Chapter 7 Summary Questions How are home wireless networks vulnerable?How are home wireless networks vulnerable?

47. © 2008 Prentice-Hall, Inc. 47 Chapter 7 Summary Questions What is a firewall and how does it keep my computer safe from hackers?What is a firewall and how does it keep my computer safe from hackers?

48. © 2008 Prentice-Hall, Inc. 48 Chapter 7 Summary Questions From which types of viruses do I need to protect my computer?From which types of viruses do I need to protect my computer?

49. © 2008 Prentice-Hall, Inc. 49 Chapter 7 Summary Questions What can I do to protect my computer from viruses?What can I do to protect my computer from viruses?