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Firewall Testing About VESARiA |
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2 Background and Firewall Basics
Before being able to understand a complete discussion of firewalls,
it's important to understand the basic principles that make firewalls
work.
2.1 What is a network firewall?
A firewall is a system or group of systems that enforces an access
control policy between two networks. The actual means by which this is
accomplished varies widely, but in principle, the firewall can be
thought of as a pair of mechanisms: one which exists to block traffic,
and the other which exists to permit traffic. Some firewalls place a
greater emphasis on blocking traffic, while others emphasize
permitting traffic. Probably the most important thing to recognize
about a firewall is that it implements an access control policy. If
you don't have a good idea of what kind of access you want to allow or
to deny, a firewall really won't help you. It's also important to
recognize that the firewall's configuration, because it is a mechanism
for enforcing policy, imposes its policy on everything behind it.
Administrators for firewalls managing the connectivity for a large
number of hosts therefore have a heavy responsibility.
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Vesaria
3640 Fords Lane, Suite D
Baltimore, MD 21215
443 - 501 - 4044
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