ZyXEL Communications wireless n gigbit router zyxel Manual Do Utilizador

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Chapter 13 Firewall
NBG-460N User’s Guide
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• Use  the  Services screen (
) 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.