There are two versions of the Internet Protocol (IP): IP version 4 and IP version 6. Each version defines an IP address differently. Because of its prevalence, the generic term IP address typically still refers to the addresses defined by IPv4. The gap in version sequence between IPv4 and IPv6 resulted from the assignment of number 5 to the experimental Internet Stream Protocol in 1979, which was never referred to as IPv5.
IP address (Internet Protocol address) is a unique number that devices use to identify and communicate with each other on a network using the standard Internet protocol. Any participating device including the routers, computers, time servers, printers, Internet fax machines, and some phone should have its own unique address. The IP address will consist of four parts from 18.104.22.168 to 255,255,255,255, but some of these values are reserved for specific purposes.