Networking and Security Study Guide

OSI Model

A framework that describes the functions of a networking system in seven layers.

Network Layer (Layer 3)

Responsible for routing and forwarding packets.

Presentation Layer (Layer 6)

Responsible for data translation, encryption, and compression.

Transport Layer (Layer 4)

Ensures reliable transmission with error checking and flow control.

Data Link Layer (Layer 2)

Handles the transfer of data between adjacent network nodes.

Application Layer (Layer 7)

Interacts directly with end users and applications.

Session Layer (Layer 5)

Manages sessions between applications.

Physical Layer (Layer 1)

Transmits raw bitstreams over a physical medium.

Hub

Operates at the Physical Layer (Layer 1) and connects multiple devices.

Switch

Operates at the Data Link Layer (Layer 2) and directs data frames.

Router

Operates at the Network Layer (Layer 3) and routes packets between networks.

Bridge

Connects two or more networks and filters traffic by MAC address.

Repeater

Regenerates and amplifies signals over long distances.

Access Point

Connects wireless devices to a wired network.

Ping Command

Tests reachability to another host using ICMP Echo Request.

ipconfig

Displays IP configuration on Windows.

ifconfig

Linux equivalent of ipconfig.

tracert Command

Shows the route a packet takes to a destination on Windows.

traceroute Command

Used to trace a packet route in Linux.

nslookup Command

Displays DNS information and troubleshoots name resolution.

netstat Command

Displays all active connections and listening ports.

ARP Command

Displays IP-to-MAC address mappings in the ARP cache.

dig Command

Analyzes DNS queries in detail.

scp Command

Securely copies files over SSH.

PAN

Personal Area Network interconnecting personal devices.

LAN

Local Area Network covering small geographical areas.

WAN

Wide Area Network spanning large geographical areas.

SAN

Storage Area Network providing block-level storage access.

CAN

Campus Area Network connecting multiple LANs.

MAN

Metropolitan Area Network covering a city or town.

Bus Topology

A single central cable with terminators at each end.

Star Topology

All devices connect to a central device like a switch or hub.

Ad-hoc Network

Peer-to-peer wireless network without a centralized access point.

Infrastructure Network

Devices connect through an access point and wired backbone.

Hypervisor

Software that runs virtual machines (VMs).

Type 1 Hypervisor

Runs directly on hardware.

Type 2 Hypervisor

Runs on a host operating system.

IaaS

Infrastructure as a Service, providing virtualized computing resources.

SaaS

Software as a Service, software accessed via a web browser.

PaaS

Platform as a Service for developers to build and deploy applications.

CIA Triad

Confidentiality, Integrity, and Availability.

Zero-Day Exploit

A vulnerability unknown to the vendor.

Phishing

A social engineering attack to obtain sensitive information.

Buffer Overflow Attack

Overwriting memory space leading to potential execution of malicious code.

Intrusion Detection System (IDS)

Monitors traffic for suspicious activity.

Honeypot

A decoy system to lure attackers and analyze their behavior.

Mandatory Access Control (MAC)

Access determined by system-enforced rules.

Role-Based Access Control (RBAC)

Access granted based on user role.

WPA3

Improved wireless security that replaced WEP.

Deauthentication Attack

A denial-of-service attack that forces clients off a wireless network.

nmap

Scans a network to discover hosts and open ports.

tcpdump

Captures and analyzes packets on a network.

telnet

Command-line tool for unencrypted remote connections.

ssh

Secure remote login over an encrypted connection.

FTP

File Transfer Protocol that uses TCP for file management.

TFTP

Trivial File Transfer Protocol that uses UDP and lacks authentication.