ZyXEL Communications P-660HN-F1 User Manual

P-660HN-F1 User’s Guide

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 79   Default Firewall Action

• 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).

3
4

1
2