Simply put, you are playing with fire if you aren’t using a firewall to protect your PC and home network from unauthorized access from outside your network.
The term “firewall” originally referred to a physical barricade against the potential spread of fire. In home computing terms, a firewall is a component of a computer or network that acts as a barrier between your home network or PC and the Internet. The firewall blocks unauthorized access while allowing authorized access to your systems. Firewalls can be hardware devices or based in software, both serving the same function.
Firewalls work by inspecting all traffic, both inbound and outbound, and deciding whether the traffic is denied or allowed passage based on a set of pre-established rules or policies. These rules and policies can work in one or more of several methods: