59.5. Overview of Host and Service Conversion Functions

Computers represent IP addresses and port numbers in binary. However, humans find names easier to remember than numbers. Employing symbolic names also provides a useful level of indirection; users and programs can continue to use the same name even if the underlying numeric value changes.

A hostname is the symbolic identifier for a system that is connected to a network (possibly with multiple IP addresses). A service name is the symbolic representation of a port number.