4.1.2 Port Numbers (1/3)
nThe concatenation of IP address and Port
Number provides a unique
identifier for transferring information between a source and a destination. This is known as a socket, the door between an application and the underlying
transport system.
nEach
application service is allocated a unique port number:
–FTP - 21
–Telnet - 23
–Domain Name Server - 53,
etc.