Meaning – The term firewall, refers to a functional unit that protects and controls the connection of one network to other networks. The firewall (a) prevents unwanted or unauthorized communication traffic from entering the protected network and (b) allows only selected communication traffic to leave the protected network.
A firewall mechanism can also be found inside every computer, and its main task is to flag applications that seem suspicious and hold potential threats to the system as a whole. However, there are some genuine applications that can appear suspicious to the firewall, mostly due to their programming, and in such cases, you can instruct the firewall to give the selected application, permission to operate on the system.
Example of usage – “He was eager to play the new game that he had downloaded onto his system. However, every time he tried to run the program, he would get an alert on the firewall and the game would not open.”