Chapter 7 Firewalls; Overview; What You Can Do In The Firewall Screens; What You Need To Know About Firewall - ZyXEL Communications P-660R-F1 series User Manual

7.1 Overview

This chapter shows you how to enable and configure the ZyXEL Device firewall. Use these screens
to enable and configure the firewall that protects your ZyXEL Device and network from attacks by
hackers on the Internet and control access to it. By default the firewall:
• allows traffic that originates from your LAN computers to go to all other networks.
• blocks traffic that originates on 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 48 Default Firewall Action
LAN
A

7.1.1 What You Can Do in the Firewall Screens

• Use the General screen to enable firewall and/or triangle route on the ZyXEL Device, and set the
default action that the firewall takes on packets that do not match any of the firewall rules.
• Use the Rules screen to view the configured firewall rules and add, edit or remove a firewall rule.
• Use the Threshold screen to set the thresholds that the ZyXEL Device uses to determine when
to start dropping sessions that do not become fully established (half-open sessions).

7.1.2 What You Need to Know About Firewall

DoS
Denials of Service (DoS) attacks are aimed at devices and networks with a connection to the
Internet. Their goal is not to steal information, but to disable a device or network so users no longer
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