What is the solution used nowadays?
As a temporarily solution to alleviate the lack of IPv4 addresses, NAT (Network Address Translation) is being deployed. NAT is a networking protocol that allows networks of private IP addresses to be set up using a single real IPv4 address. Using NAT, a local area network (LAN) can be set up with no special configuration of the Internet connection. To the Internet, the network looks like one computer, but on the LAN, every computer has its own internal IP address.