Computer Networks and Cybersecurity Fundamentals

Study Notes

TCP/IP Model: A 4-layered model that enables communication over the internet
- Network Access Layer: Defines how devices access the network
- Internet Layer: Routes data between networks
- Transport Layer: Ensures reliable data transfer
- Application Layer: Supports functions such as email and file transfer
TCP (Transmission Control Protocol): A transport-layer protocol that ensures reliable, error-checked data transfer
IP (Internet Protocol): A network-layer protocol that routes data between networks

Threats:
- Malware: Malicious software (viruses, worms, trojans, spyware)
- Phishing: Fraudulent emails or messages to obtain sensitive information
- Ransomware: Malware that demands payment in exchange for data
Security Measures:
- Firewalls: Network devices that control incoming and outgoing traffic
- Encryption: Protects data in transit using encryption algorithms
- Access Control: Limits user access to resources based on privileges
Best Practices:
- Regularly update software and operating systems
- Use strong passwords and two-factor authentication
- Back up critical data

Types of Wireless Networks:
- WLAN (Wireless Local Area Network): Connects devices in a limited geographical area
- WAN (Wireless Wide Area Network): Covers a larger geographical area
- WPAN (Wireless Personal Area Network): Connects devices in a small area (e.g., Bluetooth)
Wireless Network Topologies:
- Infrastructure Mode: Devices connect to a central access point
- Ad Hoc Mode: Devices connect directly to each other
Wireless Network Security:
- WEP (Wired Equivalent Privacy): An older, insecure encryption protocol
- WPA (Wi-Fi Protected Access): A more secure encryption protocol
- WPA2: The current, most secure encryption protocol

Cloud Deployment Models:
- Public Cloud: Shared resources, accessible over the internet
- Private Cloud: Dedicated resources, accessible within an organization
- Hybrid Cloud: Combination of public and private clouds
Cloud Service Models:
- IaaS (Infrastructure as a Service): Provides virtualized computing resources
- PaaS (Platform as a Service): Provides a development platform
- SaaS (Software as a Service): Provides software applications
Cloud Benefits:
- Scalability: Resources can be easily scaled up or down
- Cost-Effectiveness: Reduced capital and operational expenditures
- Reliability: Built-in redundancy and disaster recovery

Network Topologies:
- Bus: A single cable connects all devices
- Star: Devices connect to a central hub or switch
- Mesh: Each device connects to every other device
Network Protocols:
- HTTP (Hypertext Transfer Protocol): Transfers data over the internet
- FTP (File Transfer Protocol): Transfers files between hosts
- DNS (Domain Name System): Translates domain names to IP addresses
Network Devices:
- Routers: Forward data packets between networks
- Switches: Forward data packets within a network
- Gateways: Connect multiple networks together