One of the first lines of security defense that companies (and individuals) should perform is to enable a firewall. Today, most routers include a firewall, most personal-computer operating systems provide a firewall, and their are a variety of network (hardware and software) firewalls available. For this discussion:Define the term firewallDiscuss the goal(s) of a firewallDescribe different types of firewalls (router, server, personal computer, network) and when users should use eachList several commonly available (open source) firewallsDescribe best practices for using a firewall