Technologies such as NAT have delayed the problem by allowing many devices to use a single IP address, but a larger address space is needed to serve the modern Internet.
Ranges 127.x.x.x are reserved for the loopback or localhost, for example, 127.0.0.1 is the loopback address. Range 255.255.255.255 broadcasts to all hosts on the local network.
all ports above 400 ends with S, which stands for Secure
official_service_name port_number/protocol_name aliases