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.