While the term "firewall" creates a powerful visual picture, in reality, it doesn't involve any fire or pyrotechnics.
A computer firewall is used to protect a networked server or client machine from damage by unauthorized users.
The firewall can be either hardware or software-based.
A router is a good example of a hardware device that often has a built-in firewall.
Software programs that monitor and restrict external access to a computer can also serve as firewalls.
A network firewall allows only certain messages from the
Internet to flow in and out of the network. So, I guess in a way it really is like a wall of fire. Well, sort of.