Learning Python Networking - Second Edition

Getting information about ports, protocols, and domains

The socket module provides the socket.getservbyport(port[, protocol_name]) method, which allows us to get the port name from the port number. For example:

>>> import socket>>> socket.getservbyport(80)'http'>>> socket.getservbyport(23)'telnet'

We can also get information about the service name at the application level if we pass the protocol name as a second parameter.

You can find the following code in the socket_finding_service_name.py file:

#!/usr/bin/env python3import socketdef find_service_name():    protocolname = 'tcp'    for port in [80, 25]:        print ("Port: %s => service name: %s" %(port, socket.getservbyport(port, protocolname))) print ("Port: %s => service name: %s" %(53, socket.getservbyport(53, ...