Firewall: A Wall Providing Security To Your ‘castle'

By Author: Nick Gray
Total Articles: 9
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There are several circumstances in which you don't want to limit the access to your system from external entities or customize the entropy coming your way. You might want to restrict your children's web surfing habits, you want to stop your network's hosts from accessing the mainframe computer, or any other reason due to which you want to restrict the access of your computer or limit the traffic entering your system then there is a software which will do the perfect job for you and provide you security as well as stress free surfing experience, that software is Firewall.

Most of you might have heard of Firewalls but they are not just implemented in software forms, they can also be implemented in hardware form. The term ‘Firewall' means basically a wall which protects your software. It first made its appearance around 1988 as packet filter Firewalls. These systems became the first generation of this software application. There followed two other generations of Firewalls namely Application Layer which worked on protocols and checked them and Stateful ...
... filters which inspected each individual packet entering the system and treating it separately. Thus security provided by Firewalls improved as Firewalls evolved from time to time.

Talking about the types of Firewalls, they can be classified in 4 different types namely Packet filter, Application Gateway, Circuit-level gateway, and Proxy server. Packet filter, as the name suggests it filters every packet and checks if the packet follows the pre-defined rules or not. If it violates the rules it discards the packets. The problem with this kind of Firewalls is that it cannot work on IP spoofing. Talking about Application Gateway, they are a gateway for specific applications working on web like Telnet, FTP, etc. They provide high level resistance to restricted content. Circuit level gateway is an intelligent arrangement which comes into action during TCP or UDP connections are established. The packets need not more filtering under this arrangement. Lastly the proxy server works as a network gateway and all traffic flows in and out of a network across it and it also helps in obscuring the true address.

A lot can be talked about Firewalls as it is a very wide topic. But basically we need to understand that it is a filtering mechanism to put a check on the content flowing in your system. It is highly recommended that you always keep your Firewall enabled and configured.