Firewall is a security guard between networks and it manages and controls the traffic on the networks. It protects the system from viruses, software bugs and malicious software applications from the networks or the IP of the system. Some of the most commonly used firewall applications are Iptables, IPCop firewall, Shorewall, Uncomplicated Firewall (UFW), Pfsense and IPFire. Iptables is the most flexible utility, which supports the features like backup and restoration.