What Is A Firewall And How Does It Work..?
A Firewall is either Hardware or Software based Network Security System that controls incoming and outgoing Network Traffic. Firewalls are categorized as either Network Firewalls or Host-based Firewalls. Network Firewall filter traffic between two or more Networks and Host-based Firewalls run on host computers. It control network traffic in and out of those machines.
Firewalls works as a First Line of Defence in Network Security since 25 Years. It also established a barrier between Secure and Control internal networks that can be trusted and untrusted other networks, like Internet.