What is a firewall?

What is a firewall?

A firewall is software that intercepts the data between the Internet and your computer. It is the TCP/IP equivalent of a security gate at the entrance to your company. All traffic (data) must pass through it, and the security guard (firewall) there allows only authorized people (data) to pass into the facility (computer).

Today’s advanced software firewalls are very effective at protecting your computer from hackers and "Trojan Horse" programs like Back Orifice and Netbus. The firewall has complete control of everything incoming and outgoing on your computer. It warns you anytime a program attempts to access the internet. Everything coming in or going out must go through the firewall. Even Windows, Internet Explorer and your email program must have permission from the firewall to access the internet.

One of the most important tasks a firewall has is regulating outbound internet access. For example, if you installed a program like ICQ (chat and file exchange program), the firewall must allow ICQ to connect to the internet. The first time you ran the ICQ program, the firewall would pop up a message asking you if you want ICQ to have access to the internet. Depending on the exact firewall you have installed, you would either just click "yes" to allow ICQ access, or you would create a rule allowing inbound and outbound access for that program. From then on the firewall would know to allow ICQ access to the internet without asking you each time (unless you decided to remove ICQ access for some reason). On the other hand, if you got a Trojan program on your computer like Netbus, when the firewall asked you if you wanted to allow Netbus access to the internet, you would just click "no" to block it, and it would be stopped in its tracks.

Perhaps more important then the regulating of outgoing connections is the regulating of incoming connections. Without a firewall your computer is open to many forms of attack by hackers. Hacking tools like port scanners that can easily scan every one of the over 65,000 ports on your computer within minutes are available to anyone for free on the internet. When a hacker uses a port scanner on your computer he is looking for an open port that he can gain access to your computer through. The port scanner scans your computer ports, asking your computer one by one if each port is open or closed. Your computer being the nice guy that it is, automatically sends a response telling whoever asked if the port is open or closed. All this can and does go on without you ever knowing anything about it. What is bad is that even if every port on your computer is closed (which is rare on a Windows computer) the hacker still knows that the port and your computer exists, so he can come back another time and try again.

A good firewall can make a hackers port scanner absolutely worthless. Today’s top firewalls make each and every port on your computer completely "stealth". Stealth means that to a hacker the port is neither open nor closed, it is not there. If you're using a good firewall and a hacker runs his port scanner on your computer, he will get no reply at all, just like your computer doesn't exist. The firewall blocks all the incoming requests from the port scanner, not allowing your computer to respond to them. Therefore, the hacker will get no information about your computer ports at all, either open or closed. No port means no connection and no way into your computer. The hacker might as well move on to easier prey.

The security experts at Cyber Kreations can come to your home or business and install a top rated firewall on your computer for only $50. Email us at webmaster@cyberkreations.com or call (979) 299-9755 for more information.

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