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Welcome students, I look forward to working with you this semester, check this site frequently for updates and assignments.
~ JON ~
| Chapter 3 Notes |
| Chapter 4 Notes |
| Chapter 5 Notes |
| Chapter 6 Notes |
| Chapter 7 Notes |
| Chapter 8 Notes |
| Chapter 9 Notes |
| Port Identification |
~ IST ~
Chapter 7
Networking fundamentals
Computer network:S
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
Client computers:
Users
Server computers:
Provide resources to clients
Central network control
Internet
A large, multiserver,
multiclient network.
Network components
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
Transmission media
Provides communications channel between nodes
Forms of media:
Telephone wire:
Twisted pair
Computers are connected to a houses telephone wiring to create a network
Home phoneline network adapter is used to connect nodes to phone jacks
Coaxial cable
Fiber-optic cable
Radio waves:
Wireless
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
Bandwidth:
Data transfer rate
Throughput
Network Adaptors
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
Windows XP has a Network setup wizard
Computer threats
Cybercrimes are criminal acts conducted through the use of computers by cybercriminals.
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
Virus and Backdoor programs
Trojan horse
Zombies
How does a pc 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
A Virus main goal is to Replicate themselves:
Slow down networks
Secondary objectives:
Annoying messages
Delete files on the hard drive
Change computer settings
Types of Virus
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
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
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.
Protect your wireless network
Wireless network range doesnt 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 safeguards
AnitVirus Programs
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