Task 2 - Install a Personal Firewall

I have mentioned in the last section that it is impossible to have a software 100% bugs free, and hence impossible to close every security holes in the system since many remain to be discovered. And also quite often we do get behind in keeping our system properly patched. And because of that we need other tools to protect us for situation like those.

Install and use a firewall program on your computer. What is a firewall anyway? A firewall is a system designed to prevent unauthorized access to or from a private network. Without going into too much details about how firewall works, put simply, it is a guard that checks the incoming or outgoing data traffic. The firewall determines who can go out and who can come in through its security check point. Any unauthorized traffic will be blocked. So any intruder from outside your network wants to come in, they will be blocked from doing so. It does a reasonable good job at keeping unwanted intrusion out, when configured properly.

Keeping external intruders out is probably easy to understand. But what about keeping inside traffic from going out? What's the purpose of this? In the later section we will be looking at viruses, spywares and adwares. When you understand how these work, then it would be easy to understand why inside traffic going out to the Internet needs to be monitored as well. Viruses, spywares, adwares propagate themselves or send out information from your computer to the Internet, without your knowledge. With a firewall in place, an alarm could be sounded, example a popup message warning you that an unknown source is sending information to the Internet. At which point you may grant permission for it to go through (if you know the source) or deny it. The whole point is, the firewall is guarding the entrance/exit of your network to the outside world.

The firewall can be a hardware or a software implementation. Unless you have a big network to protect, a software implementation would be sufficient to protect your personal computer. There are numerous firewall software out there, some cost you some money while others are free. I personally use one called ZoneAlarm and am quite satisfied with it for my needs. You may download the free version of it, which is generally sufficient for general usage.