the role of firewall

Published: Last Edited:

This essay has been submitted by a student. This is not an example of the work written by our professional essay writers.

In today's technology the networks are very important because they allow different communities to share same data or any relevant information on other side or online. Networks could be interconnected system of things or people. The online world has grown up as unlimited in few years. And the ability of accessing the resource or data is easier with the touch of figure. The organization or networks can communicate with other organization networks outside the country. But unfortunately as with all good things there are is also a dark side, which is unauthorized access to data. These networks carry important data or sensitive data that need to protect form unauthorized access. One of most recent development in network security is role of firewall in active data network. Firewalls are getting well known software in these days. Due to every day changes in technology and security threats all the companies want to save their data from unauthorized access or virus they wants to implement a firewall with its user policies. That can keep their data save form any unknown threat .A firewall is a part of a computer system or data network that is designed to block unauthorized access while permitting authorized communications. A firewall is a barrier to keep destructive forces away from our property .It could be a system or group of system that enforce an access control policy between the networks. Some firewall play an important role in blocking the traffic and some firewall play important role in permitting the traffic .the most important thing in firewall is to understand the implement and access control policies. The firewall interrupts free communication between trusted and untested networks attempting to manage the information flow and also limit the dangerous free access.

"Firewalls are barriers between 'us' and 'them' for arbitrary values of 'them.'


The main purpose of my dissertation is studying on firewall, its types and limitations. The idea of research on firewall is to provide a brief detail on firewall security features. My work will cover the role of firewall in live environment like in active data network after that I will explain its different policies, limitations and what a firewall can do such as protect form DoS attack, internal attack as well as protect us from ourselves. In network security policies I will describe the minimum security policies for the user. For example password, type of connection allowed etc. How to handle an incident? My research area will also include the possible benefits of firewall, for example how it controls the access to data network. I will analysis the ability to track network use locate network abuse spy etc. With all these benefits I will research on firewall disadvantages like why we should not use a firewall, for example it can interfere with the valid traffic or it can block the actual traffic. It can give a false sense of security. It can ignore the internal threats. The role of proxy server which is most important factor in data networks will be explained. There are different books and journals on network security which will help me to study about my objectives.

Back ground

The idea of creating the firewall is to protect the internal data or information from outside the network. The idea of firewall to keep out the intruders back thousand years. For example over two thousand years ago the Chinese built the Great Wall of China as protection from neighbouring the northern tribes. In late 1980`s then there was development in networking by using the routers that separate the network form other. Firewall technology emerged in the late 1980s when the Internet was a fairly new technology in terms of its global use and connectivity. The predecessors to walls for network security were the routers used in the late 1980s to separate networks from one another. The firewall has been existing since about 1987.In the future challenges for network firewall will be network growth such as if we expand the network then firewall should protect the expended network as well. Firewall is not basically use to prevent form attack but they reduce the security risk.

* What a network firewall is.

Firewall set up is use to control the traffic flow in two data networks. It ensures the data protection and works by blocking certain types of traffic between source and a destination. All data networks have its source and destination protocols like TCP, UDP, and ICMP.A data networks firewall protects a network from unauthorized access. Data network firewall can include a hardware or software program or it could be combination of two. It basically guards the internal computer networks against any unauthorized or malicious access from outside. It also provides limited access to end user. Such as in college lab IT students can only use the limited software but they cannot download and run them on lab computers. As well as they cannot use chat software. They common type of network firewall is proxy server. These networks provide safety by hiding the internal LAN address from outside internet. The firewall allows different roles that allow limited authorization to limited users. For example Most firewall blocks all the traffic coming from the internet. This is good. It creates some problems we want to give some access to limited users. Such as if we want to allow user to access the network we need to create a role allowing such authorization such as this specific user can access the FTP server. If a user has a problem running a program which is connected with internet through the firewall .then firewall allows to change the setting up on to DMZ it stands for demilitarized zone. Which is basically portion of network that is accessible from the internet but separate form other networks.

* Why network wants a firewall.

There are different type of communities on the internet some are try to break your personal or sensitive information as well as try to get access to system though the network .And some people try to get real work done over the internet. The main purpose of firewall is to keep out the jerk out of network while still letting to get job done. There is a possibility when we go to internet we put our sensitive data at risk from attack by hacker in internet. It is possibility that the hacker can use our personal data in any criminal activities. Firewall save our sensitive data from any unauthorized activities. Firewall in data network saves the computer in large company such as if we suppose a company with 100 employee with hundred remote computers. And the entire hundred computer have a network card that connect them with the network as well as the company will also have an internet connect it could be one or more by some link T1 or T3 line. If we consider this network without firewall so its means any one can access them with any permission directly from internet. And they can make direct FTP connection to them. There is a possibility that any employee makes a mistake and leaves a security hole. So the hacker can get in to the machine. By using the firewall the company will place a firewall at each connection to internet such as T1 line that is coming to company. The firewall will provide some security rules inside the company out of 100 computers only one or two will allow receiving the FTP traffic. So other computer will be saving. So company can select which one is work like FTP or Telnet etc. The company can set up some rules like how employee will connect to internet and what file can be accessed .so firewall give tremendous control over the network as well as provide different method to control the traffic.

In data network there are two types of data threats are common complete data destruction and another one is data tempering. In compete the there is a possibility the hacker can get into the network and remove all the organization backups, it could be employee record or customer accounts etc. The second one is less dangerous than the previous one in this one the hacker or intruder temper with data or change the data integrity .the hacker will change the actual state. These changes can be roll back by using the backup.

* When we need the firewall.

First of all we need to understand the requirement of firewall in a proper networking environment. The installation is likely should have to direct control to each machine which is connected to network. The firewalls are tools used to implement network security policy so it require clear picture of network architecture. No firewall design ever be help full without first clearly defining the ultimate security policy goals.

* What can a fire wall protect against

It allows user to remote login in which the user can log in into specific remote computer. It also allow the application back door as well as STMP it is mail transport protocol that allows a network to send and receive the e-mail via STMP. It also save a network from e-mail bomb that can send 100 or 1000 of e mail to network till it gets full. Network firewall also save a network form vinous and spasm. the fire wall cannot protects against any attack which does not go through the firewall. There any many network or organizations that are worried about their data leakage outside the network though the router.

Aims and Objectives

The main objectives include deep study of different firewalls in different network environments .There will be 75 % research base and 25% practical. There are some front line objectives such as * Purpose of firewall in active data network * General study of firewall. * What kind of firewalls are available * Where a firewall located * Introduction to firewall policies. * Introduction to packet filtering. * Firewall approaches * Firewall encryption * Introduction to proxy server how they work * Role of proxy server in firewall * Comparison of different installed firewalls in active data network * What is a Good Security Policy

These are front line objective they will be further discussed with examples in main dissertation such as different types of protocols like TCP/IP, data encryption. As well as I will explain how intruder try to get in into the network through the firewall. After the all the research I will install the latest firewall and configure them and I will make comparison between those firewalls that will be shown in my practical of my dissertation which will be 25% of my total work.

Research Methods/Results

There is different work has been done on firewall in different time periods such as firewall products have changed a great deal over time a well. Firewall has existed since about 1987 and there are several surveys and history already been written but none of them provide the both depth of survey.

"Alec Muffett" "1994 wrote a paper in which he provides the excellent review of the firewall policies and architecture of time. This paper becomes the implementation of firewall also describing the technologies and how to maintain a firewall". If there is a will then there is a way so if there is no problem we will not find the problem solution. If there is no threat or security risk so we will not work on network security to make it batter. To improve the tool that enhance the security of our network we need to find the types and kind of security threats which can effect out sensitive data.

My research method will be internet browsing, book study, journals, blogs and any available online digital library such as or That will help me to research about my objectives. The result of my research work will depend upon my practical work. I will analysis the different network firewalls by installing them into any small network. The difference will be written in periodic form such as tables. There will be conclusion writing about which firewall was most easy to install and easy to operate. And which one is user friendly.


After general study of network firewall for this proposal the main problem for firewall is always open internet connection it is similar like leaving a car running with the key in it and its door are unlocked which may invite the thief to steal it. A firewall is like a military check point it stop all traffic in and out of network. It inspect the traffic to se weather it meets the network polices. After that it allows or denies the traffic base on security policies. It's like a real check point that slows the traffic. It could be a feeling of increasing the security that any network or its content being protected. As a network server is expensive to purchase and it is hard to setup on large scale but it still remain the security solution for its contents. In conclusion to prevent the internal data network any threat or attack a firewall is absolutely necessary. Based upon the acknowledge of about the attacks the feature of each type of firewall or network security can be realized as much as possible. When we look at the future of firewall there are different opinions such as some says that the firewall has no future, like with web 2.0.The reason of this dispute is the corporate worker are blocked from the new business application offered by companies such as Google Inc and Skype ltd. A firewall alone is not a solution of the problem of securing the network. The main aspect is employee or user need to understand the and well informed to see the security of their computers that are connected with the network. The system need to be maintained on regular base in order to meets the change in technologies. There is a need of introducing the policing and guidelines among the user or employees. A reliable system will have multiple layer of security so if any layer can fail so it does not effect on all components or it does not loss the control of network.


  • "A History and Survey of Network Firewall" Accessed 2002 Feb 20 R. Anderson. (2002) "Security Engineering", John Wiley & Sons, Inc.