ZyXEL Communications NBG4115 User Manual

User’s Guide

Use these screens to enable and configure the firewall that protects your NBG4115 
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 73   Default Firewall Action

• Use  the  General screen (

) to enable or disable the 

NBG4115’s firewall.

• Use  the  Services screen (

) screen enable service 

blocking, enter/delete/modify the services you want to block and the date/time 

you want to block them. 

3
4

1
2