chapter twelve

12 Networking

 

This chapter covers

  • Network types and devices
  • Addressing (including physical and logical ports)
  • Networking models
  • Network segmentation and Virtual Private Networks (VPNs)

Computer networks can vary from small, local systems to extensive global infrastructures, like the Internet, which connects billions of devices around the world. These networks differ greatly in size and complexity. At their core, networks consist of interconnected devices, such as computers and servers, that exchange data to enable communication, collaboration, and efficiency within organizations. While this connectivity offers remote access to information and resources, it also introduces significant security risks.

Networks are appealing targets for attackers. Compromising a single device can grant attackers unauthorized access to sensitive data or allow them to access other connected systems. Attackers can intercept information, manipulate network traffic, or remain undetected within a network for extended periods. Therefore, cybersecurity professionals must understand how networks function to protect their components and secure the data flowing between them.

12.1 Networking Overview

12.2 Network Components

12.2.1 Endpoint devices

12.2.2 Network Interface Cards

12.2.3 Hubs and Repeaters

12.2.4 Switches

12.2.5 Routers

12.2.6 Wireless Access Point (WAP)

12.2.7 Proxy Servers

12.2.8 Firewalls

12.2.9 Connection links

12.3 Types of Networks

12.3.1 LAN, MAN, WAN, HAN

12.3.2 Wired and Wireless Networks

12.3.3 Internet of Things (IoT)

12.4 Addressing

12.4.1 MAC Addresses

12.4.2 IP Addresses

12.4.3 DNS

12.5 Networking Models

12.5.1 Data communication layers

12.5.2 Application (upper) layers

12.5.3 Encapsulation and Decapsulation

12.5.4 Layer responsibilities

12.6 Logical Ports

12.6.1 Well-known ports and port ranges

12.6.2 Secure ports and secure protocols

12.7 Network Segmentation

12.7.1 Physical segmentation

12.7.2 Virtual Local Area Networks (VLANs)

12.7.3 Subnetting

12.7.4 Micro-segmentation