Technology in Action

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2. Technology in Action Chapter 7 Networking and Security: Connecting Computers and Keeping Them Safe from Hackers and Viruses

3. Chapter Topics • Networking fundamentals • Network architecture • Network components • Peer-to-peer networks • Ethernet networks • Computer threats • Computer safeguards • Computer viruses

4. Networking Fundamentals • Computer network: • Two or more computers connected together • Devices connected to networks: nodes • Benefits of a network: • Sharing resources • Transferring files

5. Network Architecture • Network designs: • Locally administered: • Peer-to-peer (P2P) • Centrally administered: • Client/server

6. Peer-to-Peer Networks • Nodes communicate with each other: • Peers • Share peripheral devices • Used in home and small office networks

7. Client/Server Networks • Client computers: • Users who make requests • Server computers: • Provide resources to clients • Central network control • Internet • A large, multiserver, multiclient network.

8. LANs and WANs • Local area network (LAN): • Nodes are within a small geographic region: • Homes • Schools • Small businesses • Wide area network (WAN): • LANs connected over long distances: • A few miles to thousands of miles • Use telecommunications lines

9. Network Components • Transmission media • Network communication devices • Software

10. Transmission Media • Provides communications channel between nodes • Forms of media: • Twisted pair • Coaxial cable • Fiber-optic cable • Radio waves: • Wireless • Bandwidth: • Data transfer rate • Throughput

11. Network Adapters • Devices connected to or installed in nodes: • Network interface cards (NICs) • External network adapters • Enable communication between nodes

12. Network Navigation Devices • Devices that help make data flow possible • Routers: • Route data between networks • Switches: • Receive data and retransmit it to nodes on the same network

13. Networking Software • Peer-to-Peer Software • Built into operating systems that support networking • Windows • Mac OS • Client/Server Software • Network operating system (NOS) software • Windows XP Professional • Windows Server 2003 • Novell Netware • Windows Vista Enterprise

14. Types of Peer-to-Peer Networks • Wired Ethernet networks • Wireless Ethernet networks • Power-line networks

15. Wired Ethernet Networks • Ethernet network adapters are used to connect nodes • NIC card • PC Card • USB adapter • Computers are connected to each other using unshielded twisted pair cable Ethernet Phone

16. Ethernet Switches • Keep track of data packets • Amplify and retransmit signals • Keep the network running efficiently

17. Ethernet Routers • Transfer packets from one network to another • Home Internet routers transfer data from the Internet to the home network. Router

18. Wireless Ethernet Networks • Uses radio waves to connect nodes • Basically an Ethernet network that uses radio waves instead of wires • Each node requires a wirelessnetwork adapter: • Transceivers

19. Power-Line Networks • Computers are connected to a house’s electrical wiring to create a network • Power-line network adapter is used to connect nodes to electrical outlets

20. Choosing a Peer-to-Peer Network • Things to consider: - Whether you want wireless communications - How fast you want your network connection to be - Whether existing wiring is available - How much money you can spend on your network

21. Configuring Software for a Home Network • Windows • Windows Vista home versions • Network setup wizard • Wired or wireless • Windows XP • Network setup wizard • Windows 98 • Configure manually • Help has a clear instruction

22. Computer Threats • Cybercrimes are criminal acts conducted through the use of computers by cybercriminals.

23. Hackers • Anyone who unlawfully accesses a computer system • Types of hackers: • White-hat • Black-hat • Script kiddies

24. What Hackers Do • Steal information from computers: • Credit card numbers • Bank account numbers • Internet packet sniffing • Commit identity theft

25. How Computers Are Attacked • Trojan horse • Backdoor program • Zombies • Denial of service attacks

26. How Hackers Gain Access • Direct access: • Hacking software • Indirect access: • Internet connection • Logical ports

27. Computer Safeguards:Firewalls • Software programs or hardware designed to close logical ports to invaders • A firewall is built into Windows Vista • More robust firewalls are available from other vendors • Firewalls are critical if you have an always-on broadband connection

28. Protecting a Wireless Network • Wireless network range doesn’t stop at the property line • Default device and network ID settings allow intruders to enter the network • Internet bandwidth can be stolen • Computers can be vulnerable to hacker intrusion and takeover

29. Computer Threats: Viruses • A program that attaches itself to another program and spreads itself to other computers • Viruses are hidden within the code of a host program

30. How Does a Computer Catch a Virus? • Viruses copy themselves • Infect a file on your computer • Spread by sharing disks or flash drives • E-mail attachments are the most likely source of a virus

31. What Viruses Do • Replicate themselves: • Slow down networks • Secondary objectives: • Display annoying messages • Delete files on the hard drive • Change computer settings

32. Types of Viruses • Boot-sector viruses • Replicate themselves in the boot sector of the hard drive • Logic bombs • Activate when certain conditions are met • Time bombs • Viruses that are triggered by the passage of time or on a certain date • Worms • Travel between systems through networks

33. Types of Viruses • Script viruses: • Hidden on Web pages as mini programs • Macro viruses: • Attached to documents • Series of commands • E-mail virus • Use e-mail address book to distribute the virus • Encryption viruses • Compresses files using a complex encryption key • User must pay to get the files unlocked

34. 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

35. Antivirus Software • Programs designed to detect viruses: • Scan files looking for virus signatures (unique code) • Provide options for deleting or fixing infected files • Inoculate files against further infection • Detect known viruses • Antivirus programs need to be updated frequently

36. Chapter 7 Summary Questions • What is a network, and what are the advantages of setting up one?

37. Chapter 7 Summary Questions • What is the difference between a client/server network and a peer-to-peer network?

38. Chapter 7 Summary Questions • What are the main components of every network?

39. Chapter 7 Summary Questions • What are the most common home networks?

40. Chapter 7 Summary Questions • What are wired Ethernet networks, and how are they created?

41. Chapter 7 Summary Questions • What are wireless Ethernet networks, and how are they created?

42. Chapter 7 Summary Questions • How are power-line networks created, and are they viable alternatives to Ethernet networks?

43. Chapter 7 Summary Questions • How can hackers attack a network, and what harm can they cause?

44. Chapter 7 Summary Questions • What is a firewall, and how does it keep my computer safe from hackers?

45. Chapter 7 Summary Questions • Why are wireless networks more vulnerable than wired networks, and what special precautions are required to ensure my wireless network is secure?

46. Chapter 7 Summary Questions • From which types of viruses do I need to protect my computer?

47. Chapter 7 Summary Questions • What can I do to protect my computer from viruses?