Firewall Principles; The Role Of The Firewall; What Is A Firewall; How Does A Firewall Work - D-Link DFL-1600 User Manual

3.1

The Role of the Firewall

3.1.1

What is a Firewall?

When you connect your computer or your local area network to another
network, e.g. the Internet, measures need to be taken to prevent intruders
from gaining access to resources and material you consider confidential or
sensitive. In order to achieve this, a firewall must be implemented in the
network. Its task is to ensure that only approved communication is allowed
to flow between networks and that unauthorized communication is blocked
and logged.
3.1.2

How does a Firewall work?

The primary purpose of a firewall is to enforce a security policy stating who
can communicate with whom and in what way.
The firewall accomplishes this by examining the traffic that passes through
it, comparing this information to a set of rules programmed into it and
making a decision based on factors such as sender address, destination
address, protocol and ports. This allows you to install less secure network
services on your protected networks and prevent all outsiders from ever
gaining access to these services.
Most firewalls, including D-Link firewalls, ensure that network traffic
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Firewall Principles

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