Tamirat Atsemegiorgis Building a Secure Local Area Network

1 
Introduction 
In today
’s interconnected world it is irrational to believe a computer network system is 
immune from an attacks or think of it as too small to be considered as a predator by 
intruders to gain whatever advantage they need. Sometimes company owners de-
ceived by thinking that 
company’s resource are not highly valued and hence, they are 
not worth to be targeted. The reality is even at this moment companies are losing a 
significant amount money and wealth because of negligence or lack of awareness 
about the security issues.
On the other hand smart leaders are taking steps not to be victims of globally-based 
cyber-attacks. Companies
’ managers are spending a considerable amount of money to 
protect their resources and assets in order to achieve sustainable growth and stability 
on the course as desired. It is worth spending money and energy on 
asses’ network 
vulnerability and to identify the possible threats that might cause damage to the current 
system and resources. This will help in developing an effective security policy that dic-
tates what to do and by whom in the situation when a system is under an attack coming 
from inside or outside the company's premises. Hence these days it is absolutely nec-
essary for companies to pay special attention to tightening their security layers to exist 
as companies and contest at the global level.
The purpose of this project is to design a Local Area Network (LAN) for a small compa-
ny and study the vulnerability of the system and implement security measures to pro-
tect network resources and system services. To do so, I will deal with the physical and 
logical design of a LAN by building a network in a test laboratory, consisting of com-
puters, a ASA (Appliance Security Appliance) 5505 firewall, and switches and then 
configuring them for end-to-end connectivity and finally applying security layers on 
those devices needed to keep the system safe.
The goal of this thesis is to examine the security issues of the Local Area Network set 
up for a small company and build a secure LAN system and also to recommend the 

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best practices that would help to protect the network system from internal and external 
attacks. 
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