Chapter 8 Firewall Screens; Firewall Overview; Figure 50 Default Firewall Action - ZyXEL Communications ZyWALL 2Plus User Manual

This chapter shows you how to configure your ZyWALL's firewall.

8.1 Firewall Overview

The networking term firewall is a system or group of systems that enforces an access-control
policy between two networks. It is generally a mechanism used to protect a trusted network
from an untrusted network.
The ZyWALL physically separates your private Local Area Network (LAN) of computers
from the WAN (Wide Area Network) connection to the Internet and acts as a secure gateway
for all data passing between the two networks. The ZyWALL protects against Denial of
Service (DoS) attacks, prevents theft, destruction and modification of data, and logs events.
• Enable the firewall to protect your LAN computers from attacks by hackers on the
Internet and control access between the LAN and WAN.
• By default the firewall allows traffic that originates from your LAN computers and
blocks traffic that originates from the WAN.
• You should only need to configure firewall rules if you want to restrict what the LAN
computers can access or allow access from the WAN.
The following figure illustrates the default firewall action. User A can initiate an IM (Instant
Messaging) session from the LAN to the WAN (1). Return traffic for this session is also
allowed (2). However other traffic initiated from the WAN is blocked (3 and 4).

Figure 50 Default Firewall Action

Chapter 8 Firewall Screens

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Firewall Screens
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