ZyXEL Communications eir F1000, Руководство пользователя

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187
eir F1000 Modem User
’s Guide
1 3
Firewall
13.1 Overview
This chapter shows you how to enable and configure the Device’s security settings. Use the firewall
to protect your Device 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
LAN
1
A
2
WAN
3
4
13.1.1 What You Can Do in this Chapter
• Use the General screen to configure the security level of the firewall on the Device ( Section 13.2
on page 189 ).
• Use the Protocol screen to add or remove predefined Internet services and configure firewall
rules ( Section 13.3 on page 189 ).
• Use the Access Control screen to view and configure incoming/outgoing filtering rules ( Section
13.4 on page 191 ).
• Use the DoS screen to activate protection against Denial of Service (DoS) attacks (. Section 13.5
on page 194 ).