The Internet is a marvelous technology advantage that provides access to information in revolutionary ways & in a timeless manner. Its explosive growth also causes major danger that provides the ability to pollute & destroy information in even more revolutionary ways. Everyone is jumping on the Internet bandwagon today. So this leads to various attacks by the unauthorized users. In an organization, the use of some resources or data may be restricted to a few people. People who are unauthorized to use these resources can gain access to them by using the passwords of other people. Over the past few years, the organizations central intelligence agencies, U.S. department of justice & NASA have had their web sites hacked. The hackers are using very sophisticated tools for gaining unauthorized access to computer system. Therefore it is important to secure a network.
Network security is the effort to create a secure computing platform, designed so that users cannot actions thatthey are not allowed to perform but can perform the actions that they are allowed to.
One of the popular techniques to secure the network is implementing firewalls. A firewall provides not only real security but also often plays an important role as a security blanket for management. A firewall can also acts as a corporate ambassador to the Internet. Thus a firewall acts as a safety alarm in this scenario. You can use a firewall to protect your home network and family from offensive Web sites and potential hackers.
In this paper, the way of obtaining a secured network and thereby integrating the freedom and privacy by employing a proper security organization which prevents the unauthorized access caused by several intruders such as viruses, worms, Trojan horses or hackers etc,. Is discussed. This paper also presents the types of attacks and the counter measures to be taken for those attacks.
Initially, there were not many threats to network security. With the Internet becoming more popular, more companies are doing business over the web. In addition, a number of attempts to illegally infiltrate networks have increased. As a result, the need to secure networks has grown. Firewalls were implemented on networks to prevent unauthorized access from external sources. Initially firewalls were complex & unreliable hardware devices. Most of the firewalls were routers that separate a private network from other networks.
Over the years, firewalls have developed into highly reliable solutions. They protect networks from unauthorized access & play an important part in enforcing the security policy for a company. The firewall examines each packet of data that passes through it & allows the authorized data.
The Internet has made large amounts of information available to the average computer user in business, in education and at home. For many people having access to this information is no longer just an advantage, it is essential. Yet connecting a private network to the Internet can expose critical or confidential data to malicious attack from anywhere in the world and raises serious Internet security questions. Users who connect their computers to the Internet must be aware of these dangers, their implications and how to protect their data and their critical systems. Firewalls can protect both corporate networks and individual computers from hostile intrusion from the Internet, must be understood to be used correctly. This document is intended to help you achieve this understanding, and to help you choose the best firewall for your needs.
2. What is a firewall?
Firewall is a device, which is placed between something dangerous, and something to be protected. A typical firewall configuration starting from the left the physical connection to the outside world attached to a border router, which may be under the local area network administrator or another organization. A LAN network such as an Ethernet is attached to the border router. This network is known as de-militarized zone (DMZ). It provides an attachment point for the bastion hosts which provide external connection points for services such as email, web, etc
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