ZyXEL Communications NBG-417N, User Manual, Page: 140 / 279

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Firewall
13.1 Overview
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
13.1.1 What You Can Do in this Chapter
• Use the General screen ( Section 13.2 on page 144 ) to enable or disable the
NBG4115 ’ s firewall.
• Use the Services screen ( Section 13.3 on page 144 ) screen enable service
blocking, enter/delete/modify the services you want to block and the date/time
you want to block them.
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