A firewall is a network security system that can be either hardware or software-based. This system controls both the incoming as well as outgoing network traffic using analysis of data packets to decide whether the traffic should be allowed into the network. This is done by applying a rule set upon setting up the firewall. A firewall provides a barrier between one network that is trusted and secured, and one that cannot be assumed to be trusted and secure, ie the internet. Most personal computers utilize software-based firewalls.
How does a firewall affect me? There are different ways that a firewall can affect the average consumer. They are not just meant for businesses to protect themselves from security breaches and attacks.