Chapter 13 Firewall
NBG-417N User’s Guide
136
13.2 What You Can Do
•Use the General screen (Section 13.4 on page 137) to enable or disable the
NBG-417N’s firewall.
•Use the Services screen (Section 13.5 on page 137) screen 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-417N’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-417N Firewall

The NBG-417N firewall is a stateful inspection firewall and is designed to protect
against Denial of Service attacks when activated (click the General tab under
Firewall and then click the Enable Firewall check box). The NBG-417N's
purpose is to allow a private Local Area Network (LAN) to be securely connected to
the Internet. The NBG-417N 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-417N 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-417N 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.