A thought on firewall

"Firewall", as mentioned by the name, it's a wall that prevents us from get burnt. Isn't it funny?
I try to explain this in simple terms so that most people can understand(not too technical).
Anti-virus software is popular before firewall comes in. In my understanding, anti-virus is passively fight against virus, trojan horse etc. It's only when the viruses were found then the cure is implemented. This is similar to most medical situation since we do not know when will the latest diseases spread out.
Firewall works another way, it prevents the malicious entry actively. However, we decide whether our computer can be infected easily since the decision of approving or rejecting lies in our hand. Before Microsoft releases service pack 2, there are a variety of firewall.
I tried zonealarm free edition and sygate personal firewall. Both of these are quite good since the primary function are prevent malicious access(and also unauthorize sending out information from your computer). Windows XP service pack 2 includes firewall, therefore you may get the free firewall update by installing windows xp service pack 2.
In conclusion, you need both anti-virus software and firewall to really ensure your computer is in safer(not totally safe) situation. You will never know what happen next. You can download free anti virus software from http://www.download.com or go to my website for some paid firewall's introduction http://www28.brinkster.com/woeihau .

All the best!
Low Woei Hau