Using a Personal Firewall
If you own a personal computer that connects to either a private network or the Internet, a personal firewall can provide you with a certain amount of protection from hackers. Often home computers on a network share files or use common resources like a printer. If this is the case, a firewall will allow more access than when connecting to the Internet.
Accessing the Internet is a riskier venture, so the firewall controls for it should be much stricter. Incoming and outgoing data should be restricted and any unnecessary ports, standardized number used to route traffic, should be closed.
If all this sounds like “geek speak,” don’t worry. Most systems come configured relatively securely by default. If anything needs to be altered, you will receive an alert warning you.
There are two basic components to most personal firewalls. One component looks at the data coming to your computer. It determines if this data should be allowed through or not. Information on the network is grouped into chunks called packets. A packet filter analyzes each packet that comes in from the Internet and then either allows the packet to pass or not. A packet must comply with rules set up by the firewall in order to pass. If it does not meet those rules, it is dropped.
The second component sets up rules for applications. It will allow a program to either access the Internet or not. For example, a browser needs to access the Internet. Therefore, the firewall policy is configured so that sending and receiving data through post 80, the standard one, is allowed. But, securing all other ports doesn’t necessarily mean your computer is safe.
Programs use modules and those modules can become infected. By installing an antivirus program, you can detect modules, which have become infected. But there are new viruses created each day and the antivirus program can only stop those that it knows about. In cases like this, undesirable traffic could still be passed through to your computer, thus opening it up to attacks.
Firewalls cannot provide 100% protection against hackers and viruses, but they are effective at keeping out average threats as long as you keep the antivirus program up-to-date. The main rule with firewalls is, if you do not know the visitor, treat them as a risk.