Computer Networks Overview

Definition: A computer network is a collection of interconnected devices that communicate and share resources.
Types of Networks:
- LAN (Local Area Network): Covers a small geographical area, like a home or office.
- WAN (Wide Area Network): Spans large geographic areas; the internet is the largest WAN.
- MAN (Metropolitan Area Network): Covers a city or a large campus.
- PAN (Personal Area Network): A small network, typically within a range of a few meters, like Bluetooth connections.
Networking Devices:
- Router: Connects multiple networks and routes data packets between them.
- Switch: Connects devices within a single network, facilitating communication.
- Hub: A basic device that connects multiple Ethernet devices, making them act as a single network segment.
- Modem: Converts digital data to analog for transmission over telephone lines, and vice versa.
Protocols:
- TCP/IP (Transmission Control Protocol/Internet Protocol): The fundamental suite of protocols for internet communication.
- HTTP/HTTPS (Hypertext Transfer Protocol/Secure): Protocols for transferring web pages.
- FTP (File Transfer Protocol): Used for transferring files between computers.
Network Topologies:
- Star: Devices are connected to a central hub or switch.
- Bus: All devices share a single communication line.
- Ring: Each device is connected to two others, forming a circular data path.

Importance: Protecting data integrity, confidentiality, and availability in computer networks.
Threats:
- Malware: Software designed to harm or exploit devices (viruses, worms, trojans).
- Phishing: Fraudulent attempts to obtain sensitive information by disguising as a trustworthy entity.
- DDoS (Distributed Denial of Service): An attack aimed at overwhelming a network or service with traffic.
Security Measures:
- Firewalls: Hardware or software that filters incoming and outgoing network traffic based on security rules.
- Encryption: Encoding data to prevent unauthorized access, ensuring confidentiality.
- Antivirus Software: Protects against malware and other cyber threats.
- Intrusion Detection Systems (IDS): Monitors networks for suspicious activity and potential threats.
Access Control:
- Authentication: Verifying the identity of a user or device attempting to access the network.
- Authorization: Determining what an authenticated user or device is allowed to do.
- Accounting: Keeping track of user activities for auditing purposes.
Best Practices:
- Regularly update software and systems to fix vulnerabilities.
- Use strong, unique passwords and implement multi-factor authentication.
- Educate users about security risks and safe practices.

A computer network consists of interconnected devices that enable communication and resource sharing.

LAN (Local Area Network): Serves a small area, such as a home or office.
WAN (Wide Area Network): Encompasses large geographical areas; the internet qualifies as the largest WAN.
MAN (Metropolitan Area Network): Connects multiple locations within a city or a large campus.
PAN (Personal Area Network): Covers a very limited range, generally within a few meters, typical of Bluetooth connections.

Router: Facilitates connections between multiple networks, directing data packets accordingly.
Switch: Links devices in a single network, enhancing internal communication.
Hub: Offers basic connectivity for multiple Ethernet devices, operating as a single network segment.
Modem: Translates digital signals to analog for transmission over telephone lines and vice versa.

TCP/IP (Transmission Control Protocol/Internet Protocol): The essential suite of protocols governing internet communication.
HTTP/HTTPS (Hypertext Transfer Protocol/Secure): Used for the transfer of web pages across the internet.
FTP (File Transfer Protocol): A method for transferring files between computers.

Star: Devices connect through a central hub or switch, promoting efficient communication.
Bus: All devices share a singular communication line, limiting bandwidth.
Ring: Devices are interconnected in a circular format, each connecting to two others.

Protecting data integrity, confidentiality, and availability is crucial in networking environments.

Malware: Includes harmful software like viruses, worms, and trojans designed to exploit devices.
Phishing: Involves impersonation of trustworthy entities to steal sensitive information.
DDoS (Distributed Denial of Service): Attacks that overwhelm networks or services with excessive traffic, causing disruptions.

Firewalls: Act as barriers controlling network traffic based on predetermined security rules.
Encryption: Secure encoding of data to maintain confidentiality and prevent unauthorized access.
Antivirus Software: Provides protection against malware and various cyber threats.
Intrusion Detection Systems (IDS): Monitors network activities to identify and respond to suspicious behavior.

Authentication: Validates the identity of users or devices attempting network access.
Authorization: Defines the permissions granted to authenticated users or devices.
Accounting: Logs user activities for security audits and compliance.

Regularly update all software and systems to close security vulnerabilities.
Utilize strong, unique passwords alongside multi-factor authentication for enhanced security.
Educate users on potential security risks and implement safe operational practices.