The fourth version of the Internet Protocol, used to transfer data between devices online. It defines the IP address format and the structure of packets, or standard blocks of information.

IPv4 addresses are written in the form of four values between 0 and 255, separated by periods. This version of the protocol is limited to approximately 4.3 million unique combinations of IP addresses. That is no longer sufficient to identify all devices connected to the Internet. The sixth version of the protocol (IPv6) overcomes this issue.