It’s your first line of defense in protecting information you stored in your computer to get leaked out.  Firewalls are designed to work for both the hardware and the software – typically used in combination, and generally used to prevent unauthorized Internet users to gain access to private networks.  There are a few firewall techniques which you can consider using for your computer. 

 

A proxy server intercepts all messages that enter and leave the network, as well as hides the true network address. A packet filter, as the name implies inspects each packet that enters or leaves the network and based on the user configuration will accept or reject the packet. There’s also the application gateway, and the circuit-level gateway that applies security mechanisms for specific applications  such as FTP and protocol connections like TCP.