A firewall monitors all incoming Internet traffic and allows in only what is known or trusted. The traffic enters through “ports” on your PC. There are over 65,000 ports available under the Internet Protocol. Trying to manually restrict or grant access to each of these would be impossible. Firewall software does this by allowing ports that need to be open and closing off those that do not. It also makes the computer “invisible” on the
Internet so Hackers will have a much harder time finding the PC.