Introduction
Not too long ago, the “firewall” as we know it today belonged to an exclusive group of highly trained network engineers and programmers as a tool set for defending an organization’s networks.
Back then, a person really needed to know what he was doing to set up a firewall. Less than a handful of today’s commercial products were available, and most network engineers and programmers resorted to building their own firewalls. This was because, at the time, only a few organizations on the Internet had to really worry about protecting themselves.
But today, access to e-mail and other Internet resources is very much a necessity for conducting business and accessing information. However, along with the convenience that network connectivity brings, it also raises serious security concerns. In a system that is not protected with any security measures, malicious code such as viruses can infect systems and cause damage that may be difficult to repair. Unscrupulous characters on the Internet are always snooping around trying to find open computers from which they can steal personal files, personal information or create other forms of mischief. The loss of financial records, e-mail, customer files, can be devastating to a business or to an individual.
In conjunction with other security measures, firewalls can help to prevent this devastation.
What are Firewalls?
In real life a firewall is a construction that will stop the fire from spreading straight throughout the building. In the world of networking a firewall is a device that will stop (or at least does its best effort to stop - as a real firewall) unwanted networking to go from a network to another - it is a controlled gateway between one network and another. Firewalls are tools that can be used to enhance the security of computers connected to a network, such as a LAN or the Internet.
In order to avoid any interference and to prevent any intruder from coming...