Chapter 14. Understanding Firewall Fundamentals

This chapter covers the following topics:

Firewall concepts and technologies

Using Network Address Translation

Creating and deploying firewalls

The word firewall commonly describes systems or devices that are placed between a trusted and an untrusted network. A detailed understanding of how firewalls and their related technologies work is extremely important for all network security professionals. This knowledge helps you to configure and manage the security of your networks accurately and effectively.

Complete separation means that no network connectivity exists, which does not serve anyone very well. By allowing specific traffic through the firewall, you can implement a balance of the required connectivity and security. Traffic that may be identified as harmful is any traffic that compromises confidentiality, data integrity, or availability for the intended users.

Several network firewall solutions offer user and application policy enforcement that supplies protection for different types of security threats. These solutions often provide logging capabilities that enable the security administrators to identify, investigate, validate, and mitigate such threats.

In addition, several software applications can run on a system to protect only that host. These types of applications are known as personal firewalls. This section includes an overview of network and personal firewalls and their related technologies.