Scan port using Python

19 JANUARY 2019

Overview

This post will show how you can make a small and easy-to-use port scanner program written in Python.

There are many ways of doing this with Python, and I’m going to do it using the built-in module Socket.

Sockets

The socket module in Python provides access to the BSD socket interface.

It includes the socket class, for handling the actual data channel, and functions for network-related tasks such as converting a server’s name to an address and formatting data to be sent across the network. Source

Sockets are widely used on the Internet, as they are behind any kind of network communications done by your computer.

The INET sockets, account for at least 99% of the sockets in use.

The web browser’s that you use opens a socket and connects to the web server.

Any network communication goes through a socket.

code source :

    import socket
    import subprocess
    import sys
    from datetime import datetime

    subprocess.call('clear', shell=True)

    # Ask for input
    remoteServer    = input("Enter a remote host to scan: ")
    remoteServerIP  = socket.gethostbyname(remoteServer)

    # Print a nice banner with information on which host we are about to scan
    print ("-" * 60)
    print ("Please wait, scanning remote host", remoteServerIP)
    print ("-" * 60)

    # Check what time the scan started
    t1 = datetime.now()

    # Using the range function to specify ports (here it will scans all ports between 1 and 1024)

    # We also put in some error handling for catching errors

    try:
        for port in range(1,1025):
            sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            result = sock.connect_ex((remoteServerIP, port))
            if result == 0:
                print ("Port {}: 	 Open".format(port))
            sock.close()

    except KeyboardInterrupt:
        print ("You pressed Ctrl+C")
        sys.exit()

    except socket.gaierror:
        print ('Hostname could not be resolved. Exiting')
        sys.exit()

    except socket.error:
        print ("Couldn't connect to server")
        sys.exit()

    # Checking the time again
    t2 = datetime.now()

    # Calculates the difference of time, to see how long it took to run the script
    total =  t2 - t1

    # Printing the information to screen
    print ('Scanning Completed in: ', total)