For a complete computer and network security, a combination of a standard anti-virus and a spy ware removal tool is not enough. Your computer is exposed to countless threats once you access the internet. The internet is a zone where harmful elements such as trojan horse, malware, and the typical virus roams freely here and about. So in order to protect your computer from these dangerous threats, it is highly recommended that you set up a firewall on your machine.
So what is a firewall? A firewall may be hardware device, a software program or a combination of both that can be configured in order to either reject, accept or proxy some data across a network of computers. A firewall has different levels of trust.
The internet, as mentioned above, has many threats. It is also, by far, a zone with no trust. An example of a zone that may have a high level of trust is a typical local network / simple internal network where data being transmitted between member computers are fully monitored and are certified clean and harmless.
Main task. The main task of a firewall is to maintain network security by controlling the access to or from the computer. The user will be having the capability to limit the types or forms of data going in or out of his machine using a firewall. Some examples of data that may contain malicious contents are those coming from unknown sites.
Unofficial websites may also contain threats. So before accepting data such as files, folders or application installers, always make sure that your firewall does the dirty work. But before this, of course you need to properly configure your firewall tool. Indicate the sites that you fully trust and the ones that seem to bring danger to your machine.
Once you have successfully set the conditions, your resident firewall will ensure that the packets of data going through your computer would comply with the specifications you set by carefully scanning each port on your device.
Other threats. Firewalls don’t only serve as data filters into and out of your machine. They also prevent illegal access from 3rd party users. A firewall will make sure that your computer is safe from hackers, data snatchers, or just plain software trespassers who wish to infiltrate your system.
How do I set-up a firewall on my machine? If you have a machine running on Windows XP Integrated with Service Pack 2, you don’t need to activate your firewall since it will be in action by default. To enable/disable your firewall, go the Control panel, and if you have switched to classic view, click on the Windows Firewall and a dialogue box will appear. At the General Tab, either click on the radio button with label On (recommended) or the radio button with label Off. If you have no Service Pack 2, go to Control Panel, double click on Network Connections then right click on the connection you use for Internet access. Select Properties and click the Advanced Tab. Select Protect My Computer and network by preventing access to the Internet and click OK. If you don’t have Windows XP on your computer, some recommended firewall softwares that you can use are Comodo, Zone Alarm, and McAfee.
Firewall for Computer and Network Protection 
