ZyXEL NBG-460N User Guide - Page 170

About the NBG-460N Firewall, Triangle Routes

Page 170 highlights

Chapter 13 Firewall • Use the Services screen (Section 13.5 on page 172) to enable service blocking, enter/delete/modify the services you want to block and the date/time you want to block them. 13.3 What You Need To Know The NBG-460N's firewall feature physically separates the LAN and the WAN and acts as a secure gateway for all data passing between the networks. 13.3.1 About the NBG-460N Firewall The NBG-460N's firewall feature physically separates the LAN and the WAN and acts as a secure gateway for all data passing between the networks. It is designed to protect against Denial of Service (DoS) attacks when activated (click the General tab under Firewall and then click the Enable Firewall check box). The NBG-460N's purpose is to allow a private Local Area Network (LAN) to be securely connected to the Internet. The NBG-460N can be used to prevent theft, destruction and modification of data, as well as log events, which may be important to the security of your network. The NBG-460N is installed between the LAN and a broadband modem connecting to the Internet. This allows it to act as a secure gateway for all data passing between the Internet and the LAN. The NBG-460N has one Ethernet WAN port and four Ethernet LAN ports, which are used to physically separate the network into two areas.The WAN (Wide Area Network) port attaches to the broadband (cable or DSL) modem to the Internet. The LAN (Local Area Network) port attaches to a network of computers, which needs security from the outside world. These computers will have access to Internet services such as e-mail, FTP and the World Wide Web. However, "inbound access" is not allowed (by default) unless the remote host is authorized to use a specific service. 13.3.2 Triangle Routes If an alternate gateway on the LAN has an IP address in the same subnet as the NBG-460N's LAN IP address, return traffic may not go through the NBG-460N. This is called an asymmetrical or "triangle" route. This causes the NBG-460N to reset the connection, as the connection has not been acknowledged. 170 NBG-460N User's Guide

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Chapter 13 Firewall
NBG-460N User’s Guide
170
Use the
Services
screen (
Section 13.5 on page 172
) to enable service blocking,
enter/delete/modify the services you want to block and the date/time you want
to block them.
13.3
What You Need To Know
The NBG-460N’s firewall feature physically separates the LAN and the WAN and
acts as a secure gateway for all data passing between the networks.
13.3.1
About the NBG-460N Firewall
The NBG-460N’s firewall feature physically separates the LAN and the WAN and
acts as a secure gateway for all data passing between the networks.
It is designed to protect against Denial of Service (DoS) attacks when activated
(click
the
General
tab under
Firewall
and then click the
Enable
Firewall
check
box). The NBG-460N's purpose is to allow a private Local Area Network (LAN) to
be securely connected to the Internet. The NBG-460N can be used to prevent
theft, destruction and modification of data, as well as log events, which may be
important to the security of your network.
The NBG-460N is installed between the LAN and a broadband modem connecting
to the Internet. This allows it to act as a secure gateway for all data passing
between the Internet and the LAN.
The NBG-460N has one Ethernet WAN port and four Ethernet LAN ports, which are
used to physically separate the network into two areas.The WAN (Wide Area
Network) port attaches to the broadband (cable or DSL) modem to the Internet.
The LAN (Local Area Network) port attaches to a network of computers, which
needs security from the outside world. These computers will have access to
Internet services such as e-mail, FTP and the World Wide Web. However, "inbound
access" is not allowed (by default) unless the remote host is authorized to use a
specific service.
13.3.2
Triangle Routes
If an alternate gateway on the LAN has an IP address in the same subnet as the
NBG-460N’s LAN IP address, return traffic may not go through the NBG-460N.
This is called an asymmetrical or “triangle” route. This causes the NBG-460N to
reset the connection, as the connection has not been acknowledged.