An IP address (Internet Protocol address) uniquely identifies a device connected to a computer network. An IP address identifies a specific computer or other device within a network. IP addresses can be assigned locally to achieve a LAN (Local Area Network), the IP addresses can change their value depending on many factors or user's choice. An IP address is assigned to an interface that identifies a network host, a personal computer, a smartphone, a router or appliances in general. It must be considered in fact that a host will often contain many interfaces, for example: a router has multiple interfaces and for each need an IP address.