ZyXEL Communications P-320W v3, User Manual

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P-320W v3 User’s Guide
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H A P T E R
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Firewall
12.1 Overview
This chapter gives some background information on firewalls and explains how to
get started with the P-320W v3’s 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.
12.2 What You Can Do
• Use the General screen ( Section 12.4 on page 119 ) to enable or disable the P-
320W v3’s firewall.
• Use the Services screen ( Section 12.5 on page 119 ) to to enable service
blocking, enter/delete/modify the services you want to block and the date/time
you want to block them.
12.3 What You Need to Know
The following sections provide more information about the P-320W v3’s firewalls.