1. Introduction
The Internet and the e-commence are more and more popular in recent years. Researches
on the network security technologies have become very important for both government
organizations and business corporations [1].
To investigate the Security technologies in use, Gordon et al. show that use of firewall
technologies is the most popular among their respondents in USA [2]. Use of the firewall
technology is accounted for 97% of the 687 respondents. However, most firewalls in use are
based on the conventional firewall architecture. They consist of either application software or
utilities running on the PC or network nodes. The conventional firewalls are usually set up on
the entry point of the network for the organization or corporation.
A number of serious problems of the conventional firewalls can happen. First, since these
firewalls are set up in a single choke point, if the firewall is broken due to power outage or
flooding attacks, all computers in the intranet will be disconnected to the Internet.
Second, the intranet threat is also a problem confronting Management Information Systems
(MIS) in many corporations. For example, if an employee inadvertently opens a malicious email
from the Internet and infects his computer with a worm. Suddenly, all of the other
computers inside the same intranet would be infected with the worm via this employee’s
computer.
Therefore, we propose to implement a Distributed Security System implemented with am
embedded firewall to improve the efficiency of the conventional firewall. And this
Distributed Security System is shown to not only have functions of conventional firewalls but
also be able to work against intranet threats.