ZyXEL Communications AMG1302-T11C, Руководство пользователя

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AMG1302-T11C User’s Guide
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H A P T E R
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Firewall
15.1 Overview
This chapter shows you how to enable the AMG1302-T11C firewall. Use the firewall to protect your
AMG1302-T11C and network from attacks by hackers on the Internet and control access to it. 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.
• blocks SYN and port scanner attacks.
By default, the AMG1302-T11C blocks DDOS, LAND and Ping of Death attacks whether the firewall
is enabled or disabled.
The following figure illustrates the 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 81
Default Firewall Action
15.1.1 What You Can Do in the Firewall Screens
• Use the General screen ( Section 15.2 on page 167 ) to select the firewall protection level on the
AMG1302-T11C.
• Use the Default Action screen ( Section 15.3 on page 168 ) to set the default action that the
firewall takes on packets that do not match any of the firewall rules.
• Use the Rules screen ( Section 15.4 on page 169 ) to view the configured firewall rules and add,
edit or remove a firewall rule.
• Use the Dos screen ( Section 15.5 on page 174 ) to set the thresholds that the AMG1302-T11C
uses to determine when to start dropping sessions that do not become fully established (half-
open sessions).
WAN
LAN
3
4
1
2
A