Best UI to allow expert users to enter an ip address? (IPv4)

1. Who provides IPv4 address?
2. Which of the following are valid IPv4 address give justification?

Who provides IPv4 address?

So, the full IP addressing range goes from 0.0.0.0 to 255.255.255.255. IP addresses are not random. They are mathematically produced and allocated by the Internet Assigned Numbers Authority (IANA), a division of the Internet Corporation for Assigned Names and Numbers (ICANN).

Which of the following are valid IPv4 address give justification?

A valid IPv4 address must be in the form of xxx. xxx. xxx. xxx, where xxx is a number from 0-255.