Chapter 12. Securing the Network

OBJECTIVES

This chapter covers the following CompTIA-specified objectives for the “Network Implementation” section of the Network+ exam:

Identify the purpose, benefits, and characteristics of using a firewall.

• Firewalls are a means by which to secure a network from outside intruders. With the proliferation of the Internet and WAN connectivity, the use of firewalls is becoming commonplace.

Identify the purpose, benefits, and characteristics of using a proxy server.

• The Internet provides many benefits to a modern business. One of the challenges associated with being connected to the Internet, though, is providing access to all users within an organization in a controlled manner. Proxy servers are the tools that allow us to do this.

Given a scenario, predict the impact of a particular security implementation on network functionality (e.g., blocking port numbers, encryption, etc.).

• The measures used to protect networks also add a layer of complexity to these networks. Understanding how these measures operate and the consequences of changing or removing services are key skills for a network administrator.

OUTLINE

Introduction

Threats to Security

Security Responsibilities of a Network Administrator

Physical and Logical Security

Physical Security

Logical Security

Authentication, Passwords, and Password Policies

File System Security

Firewalls

The Purpose and Function of a Firewall

Packet-Filtering Firewalls

Circuit-Level Firewalls

Application Gateway Firewalls

Demilitarized Zones

Proxy Servers

Caching Proxy Servers

Using a Proxy Server

Understanding How Security Affects a Network

Blocking Port Numbers

Port Blocking and Network Users

Encryption

Internet Protocol Security (IPSec)

Data Encryption Standard (DES)

3DES

Pretty Good Privacy (PGP)

Auditing

Chapter Summary

Apply Your Knowledge

STUDY STRATEGIES

• Read the objectives at the beginning of the chapter.

• Study the information in the chapter, paying special attention to the tables, which summarize key information.

• Review the objectives again.

• Answer the exam questions at the end of the chapter and check your results.

• Use the ExamGear test on the CD-ROM that accompanies this book to answer additional exam questions concerning this material.

• Review the notes, tips, and exam tips in this chapter. Make sure you understand the information in the exam tips. If you don't understand the topic referenced in an exam tip, refer to the information in the chapter text and then read the exam tip again.