Networking And Security5

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

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

Networking Fundamentals Computer network: Two or more computers connected together Each is a Node Benefits of a network: Sharing resources Transferring files

Network Architecture Network designs: Individual PC controlled: Peer-to-peer (P2P) Centrally controlled: Client/server Peer-to-peer Client/server

Peer-to-Peer Networks Nodes communicate with each other: Peers Share peripheral devices: Printers Scanners Home and small office networks

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

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

Network Components Transmission media Network adapters Navigation devices Network software

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

Network Adapters Devices connected to or installed in nodes: Network interface cards (NIC) External network adapter Enable communication between nodes

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 network

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

Types of Peer-to-Peer Networks Power-line Phoneline Ethernet Wireless

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 RJ-45 Phoneline

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

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

Wireless Networks Use radio waves to connect nodes Basically an Ethernet network that uses radio waves instead of wires Each node requires a wireless network adapter: Transceiver

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

Phoneline Networks Computers are connected to a house’s telephone wiring to create a network Home phoneline network adapter is used to connect nodes to phone jacks

Choosing a Peer-to-Peer Network Things to consider: Existing wiring Wireless or wired Speed of the network Cost of the network $$$ $$ $ $ Relative installation and equipment costs for networking two computers 100 to 630 bps 108 Mbps 54 Mbps 100 Mbps to 1,000 bps (1 gigabit) Maximum data Transfer rate (bandwidth) Wireless 802.11n Wireless Enhanced G Wireless 802.11g Wired Ethernet Comparing the Major Types of Home Networks

Configuring Software for a Home Network Windows operating system: Windows Vista home versions Network setup wizard Wired or wireless Windows XP: Network setup wizard Windows ME: Network setup wizard Windows 98: Configure manually Help has a clear instructions

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

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

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

Denial of Service Attacks Backdoor programs Trojan horse Zombies Denial of service attacks

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

Computer Safeguards Firewalls Software 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.

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.

Computer Threat - 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

How Does a Computer Catch a Virus Viruses copy themselves Infect a file on your computer Viruses spread by sharing disks E-mail attachments are the most likely source of a virus

What Viruses Do Replicate themselves: Slow down networks Secondary objectives: Annoying messages Delete files on the hard drive Change computer settings

Types of Viruses Boot-sector viruses: Replicate themselves in the boot sector of the hard drive Logic bombs: Activate when certain conditions are met Worms: Travel between systems through networks

Types of Viruses Script viruses: Hidden on Web pages Mini programs Macro viruses: Attached to documents Series of commands Encryption viruses Search for common data files Compress files using a complex encryption key User must pay to get the files unlocked Trojan horses: Backdoor programs Control remote computers

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

Antivirus Software 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 viruses Antivirus programs need to be updated frequently

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

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

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

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

Chapter 7 Summary Questions What are power-line networks?

Chapter 7 Summary Questions What are phoneline networks?

Chapter 7 Summary Questions What are Ethernet networks?

Chapter 7 Summary Questions What are wireless networks?

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

Chapter 7 Summary Questions How are home wireless networks vulnerable?

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

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

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

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