ZyXEL Communications VMG8825-B Series, Руководство пользователя, Страница: 205 / 360

VMG8825-B Series User’s Guide
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C
HAPTER
18
Firewall
18.1 Overview
This chapter shows you how to enable and configure the VMG’s security settings. Use the firewall to
protect your VMG 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 116 Default Firewall Action
18.1.1 What You Can Do in this Chapter
• Use the General screen to configure the security level of the firewall on the VMG ( Section 18.2 on
page 206 ).
• Use the Protocol screen to add or remove predefined Internet services and configure firewall rules
( Section 18.3 on page 207 ).
• Use the Access Control screen to view and configure incoming/outgoing filtering rules ( Section 18.4
on page 209 ).
• Use the DoS screen to activate protection against Denial of Service (DoS) attacks (. Section 18.5 on
page 211 ).
DSL