Yes, that is as of now. When IPv6 gets the nod, the new IP
address may look like this: 0.0.0.0.0.0
And there won't be 4 billion users at any one time, due to the
limitations of IP addressing.
Class D and Class E IP addresses are not used, any IP address that
ends with 0 and 255 won't be used, IP addresses belonging to
hardware won't be used, any IP address that start with 0 won't be
used.
