Port Scanner using Python

Prerequisites: Socket Programming in Python

This article is just to provide a sample code to generate a Port Scanner. This Port Scanner will work for both the Web Applications as well as remote Host. This tool has been created to provide the basic functionality of a Port Scanner. The general concept of Sockets had been used to provide the functionality. Port Scanner is built on Python 3 and uses some extra libraries such as socket and pyfiglet (for a fancy banner). 

Please find the below source code for the Port Scanner : 

Source Code 

Python3

import pyfiglet
import sys
import socket
from datetime import datetime

ascii_banner = pyfiglet.figlet_format("PORT SCANNER")
print(ascii_banner)

# Defining a target
if len(sys.argv) == 2:

    # translate hostname to IPv4
    target = socket.gethostbyname(sys.argv[1])
else:
    print("Invalid amount of Argument")

# Add Banner
print("-" * 50)
print("Scanning Target: " + target)
print("Scanning started at:" + str(datetime.now()))
print("-" * 50)

try:

    # will scan ports between 1 to 65,535
    for port in range(1,65535):
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        socket.setdefaulttimeout(1)

        # returns an error indicator
        result = s.connect_ex((target,port))
        if result ==0:
            print("Port {} is open".format(port))
        s.close()

except KeyboardInterrupt:
        print("\n Exiting Program !!!!")
        sys.exit()
except socket.gaierror:
        print("\n Hostname Could Not Be Resolved !!!!")
        sys.exit()
except socket.error:
        print("\ Server not responding !!!!")
        sys.exit()

Output:

Note: In the above code at line 27 i.e for the port in range(1, 65535): you can custom define your ports under which range you have to scan. This port scanner will generally take the time of 2 mins maximum to produce output in the format, that so and so ports are open or closed.