Firewalls, 1 firewall overview, 2 types of firewalls – ZyXEL Communications P-2602HWLNI User Manual

Page 233: 1 packet filtering firewalls, Chapter 14 firewalls, 1 firewall overview 14.2 types of firewalls, Firewalls (233)

P-2602HWLNI User’s Guide

233

H A P T E R

Firewalls

This chapter gives some background information on firewalls and introduces the ZyXEL
Device firewall.

14.1 Firewall Overview

Originally, the term “firewall” referred to a construction technique designed to prevent the
spread of fire from one room to another. The networking term “firewall” is a system or group
of systems that enforces an access-control policy between two networks. It may also be
defined as a mechanism used to protect a trusted network from an untrusted network. Of
course, firewalls cannot solve every security problem. A firewall is one of the mechanisms
used to establish a network security perimeter in support of a network security policy. It should
never be the only mechanism or method employed. For a firewall to guard effectively, you
must design and deploy it appropriately. This requires integrating the firewall into a broad
information-security policy. In addition, specific policies must be implemented within the
firewall itself.
Refer to

Section 15.5 on page 248

to configure default firewall settings.

Refer to

Section 15.6 on page 249

to view firewall rules.

Refer to

Section 15.6.1 on page 251

to configure firewall rules.

Refer to

Section 15.6.2 on page 254

to configure a custom service.

Refer to