ZyXEL Communications P-324 User Manual
Firewall
12-1
Chapter 12
Firewall
This chapter gives some background information on firewalls and explains how to get started with
the Prestige firewall.
12.1 Introduction
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 an untrusted network. 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.
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 an untrusted network. 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.
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 Prestige Firewall
The Prestige firewall is a stateful inspection firewall and is designed to protect against Denial of Service
attacks when activated (click LOG SETTINGS and then click the Enable Firewall check box). The
Prestige's purpose is to allow a private Local Area Network (LAN) to be securely connected to the Internet.
attacks when activated (click LOG SETTINGS and then click the Enable Firewall check box). The
Prestige's purpose is to allow a private Local Area Network (LAN) to be securely connected to the Internet.