User's Guide

EMG3435-Q20A User’s Guide
140
C HAPTER 14
Se c urity
14.1 O ve rvie w
Use these screens to enable and configure the firewall that protects your EMG3435-Q20A and your LAN
from unwanted or malicious traffic.
Enable the firewall to protect your LAN computers from attacks by hackers on the Internet and control
access between the LAN and WAN. By default the firewall:
• allows traffic that originates from your LAN computers to go to all of the networks.
• blocks traffic that originates on the 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).
Fig ure 96 Default Firewall Action
14.1.1 Wha t Yo u C a n Do
• Use the IPv4 Fire wa ll screen to enable or disable the EMG3435-Q20A’s IPv4 firewall (
Section 14.2 on
page 141
).
• Use the IPv6 Fire wa ll screen to enable or disable the EMG3435-Q20A’s IPv6 firewall (
Section 14.3 on
page 143
).
14.1.2 Wha t Yo u Ne e d To Kno w
The following terms and concepts may help as you read through this chapter.
WAN
LAN
3
4
1
2
A