IT Baseline Protection Manual - The Information Warfare Site

Data Transmission Systems Firewall
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7.3 Firewall
Description
Firewalls are used to control communication between two
networks. Usually a firewall protects a network against attacks
originating from networks requiring a lower degree of
protection, e.g. when a sub-network requiring protection is
connected to an institution-wide network or when a company
WAN
network is connected to the Internet.
In this chapter, a firewall is a combination of hardware and
software which acts as the sole junction between two separate TCP/IP networks, one of which requires
a higher degree of protection. As a firewall of this kind is often used to protect the internal network
from attacks through the Internet, it is also called an Internet firewall.
In this chapter, only the threats and safeguards specific to a firewall are described. Furthermore, the
threats and safeguards specific to the IT system with which the fire wall is implemented are also to be
considered. It is assumed that a firewall is implemented on a UNIX system, i.e. the threats and
safeguards described in Chapter 6.2 should be observed in addition to those contained below.
Threat Scenario
The following typical threats are assumed for a firewall as part of IT baseline protection:
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IT-Baseline Protection Manual: Otober 2000
LAN