The public internet is a very large network indeed. The language used to communicate data packets between computers connected to the internet is called the Internet Protocol (IP). There are two versions of IP is use on the Internet.
IPv4 – which has addresses that are made up of 32 bits, represented by four 8 bit decimal numbers separated by a dot. Valid IP addresses range from 0.0.0.0 to 255.255.255.255 – however all are not assignable to individual computers as they serve special purposes. The address space of IPv4 is limited to 4,294,967,296 addresses and they are all but used up! You can learn more about IPv4 here.
IPv6 – To address the lack of available addresses, and several other security and management concerns, IPv6 will become the new addressing standard for the Internet. IPv6 addresses are made up of 128 bits, represented by 8 groups of 4 hexadecimal digits separated by a colon – for example 1010:0aa2:32ef:0012:065a:0023:0abb:cce2 – the address space of IPv6 is big – really big! If you had to write it down it would look something like 340,282,366,920,938,000,000,000,000,000,000,000,000 – countless trillions times more addresses than IPv4! You can learn more about IPv6 here.