ZyXEL Communications P-792H v3 - Firewalls; Chapter 10 Firewalls; Overview; What You Can Do in the Firewall Screens

P-79X Series User’s Guide
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CHAPTER 10
Firewalls
10.1 Overview
This chapter shows you how to enable and configure the P-79X firewall. Use these screens to
enable and configure the firewall that protects your P-79X 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 59 Default Firewall Action
10.1.1 What You Can Do in the Firewall Screens
•Use the General screen (Section 10.2 on page 103) to enable firewall on the P-79X, and set the
default action that the firewall takes on packets that do not match any of the firewall rules.
•Use the Rules screen (Section 10.3 on page 104) to view the configured firewall rules and add,
edit or remove a firewall rule.
•Use the Threshold screen (Section 10.4 on page 107) to set the thresholds that the P-79X uses
to determine when to start dropping sessions that do not become fully established (half-open
sessions).
WAN
LAN
3
4
1
2
A