ZyXEL Communications P-2302HWL-P1 Series - Manual (Page 189)

P-2302HW/HWL-P1 Series User’s Guide
Chapter 14 Firewall 189
C
H A P T E R
1 4
Firewall
Use these screens to enable, configure and disable the firewall that protects your ZyXEL
Device and your LAN from unwanted or malicious traffic.
14.1 Firewall Overview
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.
14.1.1 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.
14.1.2 About the ZyXEL Device Firewall
The ZyXEL Device firewall is a stateful inspection firewall and is designed to protect against
Denial of Service attacks when activated. The ZyXEL Device's purpose is to allow a private
Local Area Network (LAN) to be securely connected to the Internet. The ZyXEL Device 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 ZyXEL Device 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 ZyXEL Device 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.