ZyXEL Communications EMG6726-B10A, Руководство пользователя

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EMG6726/8726-B10A User’s Guide
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H A P T E R
17
Firewall
17.1 Overview
This chapter shows you how to enable and configure the EMG’s security settings. Use the firewall to
protect your EMG 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 120 Default Firewall Action
17.1.1 What You Can Do in this Chapter
• Use the General screen to configure the security level of the firewall on the EMG ( Section 17.2 on
page 186 ).
• Use the Protocol screen to add or remove predefined Internet services and configure firewall rules
( Section 17.3 on page 187 ).
• Use the Access Control screen to view and configure incoming/outgoing filtering rules ( Section 17.4
on page 189 ).
• Use the DoS screen to activate protection against Denial of Service (DoS) attacks (. Section 17.5 on
page 191 ).