service_name.py

#!/usr/bin/env python

# thanks to book py net prog cookbook
import socket

def 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, 'udp'))

if __name__ == '__main__':
    find_service_name()