What Is A Firewall; Stateful Inspection Firewall; Guidelines For Enhancing Security With Your Firewall - ZyXEL Communications EMG6765-Q10A User Manual

What is a Firewall?

Originally, the term "firewall" referred to a construction technique designed to prevent the spread of fire
from one room to another. The networking term "firewall" is a system or group of systems that enforces an
access-control policy between two networks. It may also be defined as a mechanism used to protect a
trusted network from a network that is not trusted. Of course, firewalls cannot solve every security
problem. A firewall is one of the mechanisms used to establish a network security perimeter in support of
a network security policy. It should never be the only mechanism or method employed. For a firewall to
guard effectively, you must design and deploy it appropriately. This requires integrating the firewall into
a broad information-security policy. In addition, specific policies must be implemented within the firewall
itself.

Stateful Inspection Firewall

Stateful inspection firewalls restrict access by screening data packets against defined access rules. They
make access control decisions based on IP address and protocol. They also "inspect" the session data to
assure the integrity of the connection and to adapt to dynamic protocols. These firewalls generally
provide the best speed and transparency; however, they may lack the granular application level
access control or caching that some proxies support. Firewalls, of one type or another, have become
an integral part of standard security solutions for enterprises.
About the EMG6765-Q10A Firewall
The EMG6765-Q10A'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 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
EMG6765-Q10A's purpose is to allow a private Local Area Network (LAN) to be securely connected to
the Internet. The EMG6765-Q10A 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 EMG6765-Q10A 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 EMG6765-Q10A 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.

Guidelines For Enhancing Security With Your Firewall

Change the default password via Web Configurator.
1
Think about access control before you connect to the network in any way, including attaching a
2
modem to the port.
Limit who can access your router.
3
Chapter 17 Firewall
EMG6765-Q10A User's Guide
128