Page 157 - DCAP516_COMPUTER_SECURITY

Unit 13: Firewalls
Manmohan Sharma, Lovely Professional University

Unit 13: Firewalls Notes

CONTENTS
Objectives
Introduction

13.1 Meaning of Firewall
13.2 Firewall Characteristics
13.2.1 Stateful vs. Stateless Firewalls

13.2.2 Rules based vs. Policy based Firewalls
13.2.3 Packet Filtering vs. Packet Inspecting Firewalls
13.2.4 Proxy Firewall
13.2.5 Network Address Translation (NAT)
13.2.6 Virtual Private Networking (VPN)

13.3 Types of Firewalls
13.3.1 Network Layer
13.3.2 Layer Firewalls

13.3.3 Circuit-Level Firewalls
13.4 Firewall Configuration
13.5 Summary
13.6 Keywords
13.7 Review Questions

13.8 Further Readings

Objectives

After studying this unit, you will be able to:

Define firewall
Explain the various firewall characteristics
Describe firewall types
Understand the methodology of firewall configuration

Introduction

A system designed to prevent unauthorized access to or from a private network. Firewalls can
be implemented in both hardware and software, or a combination of both. Firewalls are frequently
used to prevent unauthorized Internet users from accessing private networks connected to the
Internet, especially intranets. All messages entering or leaving the intranet pass through the
firewall, which examines each message and blocks those that do not meet the specified security
criteria.

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