IPv4, also known as Internet Protocol version 4, is an inter-networking method used to route internet traffic. In order to connect a device to the internet, an internet protocol like IPv4 is required. Though the supply of original IPv4 addresses has run out (an event known as the IPv4 runout), IPv4 addresses are still available for purchase on the secondary market. When purchasing IPv4, you cannot purchase a single address. Instead, it is necessary to purchase a block of addresses.