Protocol to Port Number Conversion - Python

import socket

proto_names = ['ftp', 'telnet', 'http', 'https', 'gopher']

for x in proto_names:
    print(x + '\t runs on port: \t' + str(socket.getservbyname(x)))

This Python code performs the following tasks:

1. Imports the 'socket' module using the 'import' keyword. This module provides a way to communicate over a network.

2. Defines a list 'proto_names' that contains the names of various network protocols such as 'ftp', 'telnet', 'http', 'https', 'gopher'.

3. Uses a 'for' loop to iterate over each element in the 'proto_names' list.

4. Within the loop, calls the 'socket.getservbyname()' method, passing the current element of the 'proto_names' list as an argument. This method returns the port number associated with the given service name.

5. Concatenates the service name and its associated port number as a string, and then prints it to the console using the 'print()' function.

Let's break down each line of code in more detail:

import socket

This line imports the 'socket' module into the script, which provides access to the socket interface for network communication.

proto_names = ['ftp', 'telnet', 'http', 'https', 'gopher']

This line defines a list 'proto_names' that contains the names of various network protocols such as 'ftp', 'telnet', 'http', 'https', 'gopher'.

for x in proto_names:

This line starts a 'for' loop that iterates over each element in the 'proto_names' list. The loop variable 'x' takes on the value of each element in the list in turn.

print(x + '\t runs on port: \t' + str(socket.getservbyname(x)))

This line calls the 'socket.getservbyname()' method, passing the current element of the 'proto_names' list as an argument. This method returns the port number associated with the given service name. The returned port number is then converted to a string and concatenated with the service name and some whitespace characters to form a formatted string that specifies the service name and its associated port number. The formatted string is then printed to the console using the 'print()' function.

This Python code retrieves and displays the port numbers associated with a list of common network protocols. For each protocol, the service name and its associated port number are concatenated into a formatted string and printed to the console.