What is firewall. How firewall protects your computer
It is common practice to call firewalls as walls for good reason. Firewall — it is a wall, that protects both from the inside and from the outside. From the outside the wall protects your ports from undesirable activity and entry. From the inside the wall prevents your data leak into unautghorized locaion, also the program upgrade restriction can save your traffic, especially if it is a limited one.
How firewall protects your computer. Operation principle
Imagine that your computer is equipped with a number of doors, through which computers are connected to the network, exchange the information and so on. There is no need to explain that such exchange is not always desirable and sometimes dangerous. The wall covers your doors and opens it only with your permission to those who you trust. Also the wall will not open the door and let anything that is precious for you out, including personal information and many others.
What is firewall good for
First of all it restrains all suspicious software contacts with the outside world. For some programs it is completely normal to receive and to send the formation to network, as, for example, for e-mail clients, browsers and so on. However, if the application starts go on-line by itself, or if an application, that can work without Internet connection, starts to seek the way out into the world, in such cases a firewall is needed. It is intended to sift out the whole traffic according to the rule list that was built-in on default or according to your own rules that are convenient only for tou.
Another significant aspect is the all your computer ports monitoring. The wall closes all unnecessary for the operation moment ports. Ports are ment not only for the connection with the outside world, but also the attack on your computer can be made through them. The wall resists all such unauthorized entries.
The third very important moment is the monitoring all the installed applications. With the very first application starting, firewall memorizes all the application data, also some walls can exercise such control more deeply, on all program component level.
Firewall and antivirus
After all mentioned above, this brings up the question: if there is a need in an antivirus in this case? Yes, it needs. It needs to catch destructive viruses. Such viruses don’t need Internet access, they are aimed only to destruction. Antiviruses have heuristic analyzers that can not only catch viruses registered in the pattern, but also prevent the disaster according to behaviour analysis.