ZyXEL Communications SBG5500-A, User Manual

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SBG5500 Series User’s Guide
138
C
HAPTER
9
Firewall
9.1 Overview
This chapter shows you how to enable and configure the SBG’s security settings. Use the firewall to
protect your SBG 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 108 Default Firewall Action
9.1.1 What You Can Do in this Chapter
• Use the Firewall Overview screen to activate the firewall feature on the SBG ( Section 9.2 on page
140 ).
• Use the DoS screen to activate protection against Denial of Service (DoS) attacks ( Section 9.3 on
page 141 ).
• Use the Firewall Rules screen to view the configured firewall rules and add, edit or remove incoming/
outgoing filtering rules ( Section 9.4 on page 141 ).
• Use the Device Service screen to configure through which interfaces, which services can access the
SBG ( Section 9.5 on page 144 ).
SBG