The Lost Art of AV: IPv4 & IPv6 Explained.

Internet Protocol version 4 (IPv4) is the fourth version of the Internet Protocol (IP). It is one of the core protocols of standards-based internetworking methods in the Internet and other packet-switched networks. IPv4 was the first version deployed for production on SATNET in 1982 and on the ARPANET in January 1983. It still routes most Internet traffic today,[1] despite the ongoing deployment of a successor protocol, IPv6.
Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol, the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet.