ZyXEL Communications wireless n gigbit router zyxel About the NBG-460N Firewall, Triangle Routes

Chapter 13 Firewall

•Use the Services screen (Section 13.5 on page 182) to enable service blocking, enter/delete/modify the services you want to block and the date/time you want to block them.

13.3What 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.

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NBG-460N User’s Guide