Firewall; Chapter 19 Firewall; Overview - ZyXEL Communications NBG-419N User Manual

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H A P T E R

19.1 Overview

This chapter shows you how to enable and configure the firewall that protects your
NBG-419N and your LAN from unwanted or malicious traffic.
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 to go to all of the
networks.
• blocks traffic that originates on the other networks from going to the LAN.
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 101 Default Firewall Action
NBG-419N User's Guide
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Firewall

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