What open source port scanning tool is considered to be one of the most popular and the standard for port scanning?

Examples of registered ports

A short example of registered ports that you may be familiar with are in Table 8.3 (Note that this is just a sample of the list.)

Table 8.3. Examples of Registered Ports

To develop the simplest Port Scanner in Python, I need to know just a few things:

What IP address to target?

What port range should I scan?

Whether I should display all the results or should I only display the ports that were found to be open. In other words ports that I could successfully connect to.

Figure 8.9 depicts the GUI for our simple Port Scanner. The GUI allows the user to specify the IP address to scan along with the port range. The GUI also includes a checkbox that allows the user to specify whether all the results or only the successful results are displayed.

I have provided detailed documentation in line with the program so you can walk through the program reading the comments for clarity. Figure 8.10 depicts the launch of the startup Port Scanner GUI. As you can see in Figure 8.10, I launched the program from the command line with administrative privilege. This is necessary as administrator privilege is required to perform the port scan network operations.

Before diving into the code take a look at the overall layout of the program. I recommend that you start by examining the “Setup the Application Windows” section a couple pages down in the code. Then, I would move back to the beginning of the code and examine the portScan event handler starting with “def portScan(event)”:

As you can see most of the work is related to setting up the GUI application and setting up the list of host ports to scan. Once that is done, the code that actually scans each port and checks the result is only a few lines as shown here.

# open a socket

reqSocket = socket(AF_INET, SOCK_STREAM)

# Try Connecting to the specified IP, Port

response = reqSocket.connect_ex((baseIP, port))

#

# Python Port Scanner

#

import wxversion

wxversion.select("2.8")

import wx # Import the GUI module wx

import sys # Import the standard library module sys

import ping # Import the ICMP Ping Module

from socket import * # Import the standard library module socket

from time import gmtime, strftime # import time functions

#

# Event Handler for the portScan Button Press

#

def portScan(event):

 # First, I need to check that the starting port is <= ending port value

 if portEnd.GetValue() < portStart.GetValue():

 # This is an improper setting

 # Notify the user and return

 dlg = wx.MessageDialog(mainWin,"Invalid Host Port Selection", "Confirm", wx.OK | wx.ICON_EXCLAMATION)

 result = dlg.ShowModal()

 dlg.Destroy()

 return

 # Update the Status Bar

 mainWin.StatusBar.SetStatusText('Executing Port Scan .... Please Wait')

 # Record the Start Time

 utcStart = gmtime()

 utc = strftime("%a, %d %b %Y %X + 0000", utcStart)

 results.AppendText("\n\nPort Scan Started: "+ utc + "\n\n")

 # Build the base IP Address String

 # Extract data from the ip Range and host name user selections

 # Build a Python List of IP Addresses to Sweep

 baseIP = str(ipaRange.GetValue())+

 '.'+str(ipbRange.GetValue())+

 '.'+str(ipcRange.GetValue())+

 '.'+str(ipdRange.GetValue())

 # For the IP Addresses Specified, Scan the Ports Specified

 for port in range(portStart.GetValue(), portEnd.GetValue()+1):

 try:

 # Report the IP Address to the Window Status Bar

 mainWin.StatusBar.SetStatusText('Scanning: '+ baseIP+' Port: '+str(port))

 # open a socket

 reqSocket = socket(AF_INET, SOCK_STREAM)

 # Try Connecting to the specified IP, Port

 response = reqSocket.connect_ex((baseIP, port))

 # if we receive a proper response from the port

 # then display the results received

 if(response == 0) :

 # Display the ipAddress and Port

 results.AppendText(baseIP+'\t'+str(port)+'\t')

 results.AppendText('Open')

 results.AppendText("\n")

 else:

 # if the result failed, only display the result

 # when the user has selected the "Display All" check box

 if displayAll.GetValue() == True:

 results.AppendText(baseIP+'\t'+str(port)+'\t')

 results.AppendText('Closed')

 results.AppendText("\n")

 # Close the socket

 reqSocket.close()

 except socket.error, e:

 # for socket Errors Report the offending IP

 results.AppendText(baseIP+'\t'+str(port)+'\t')

 results.AppendText('Failed: ')

 results.AppendText(e.message)

 results.AppendText("\n")

 # Record and display the ending time of the sweep

 utcEnd = gmtime()

 utc = strftime("%a, %d %b %Y %X + 0000", utcEnd)

 results.AppendText("\nPort Scan Ended: "+ utc + "\n\n)"

 # Clear the Status Bar

 mainWin.StatusBar.SetStatusText('')

# End Scan Event Handler ==========================

#

# Program Exit Event Handler

#

def programExit(event):

 sys.exit()

# End Program Exit Event Handler =================

#

# Setup the Application Windows ==================

#

app = wx.App()

# define window

mainWin = wx.Frame(None, title="Simple Port Scanner", size =(1200,600))

#define the action panel

panelAction = wx.Panel(mainWin)

#define action buttons

# I'm creating two buttons, one for Scan and one for Exit

# Notice that each button contains the name of the function that will

# handle the button press event. Port Scan and ProgramExit respectively

displayAll = wx.CheckBox(panelAction, -1, 'Display All', (10, 10))

displayAll.SetValue(True)

scanButton = wx.Button(panelAction, label='Scan')

scanButton.Bind(wx.EVT_BUTTON, portScan)

exitButton = wx.Button(panelAction, label='Exit')

exitButton.Bind(wx.EVT_BUTTON, programExit)

# define a Text Area where I can display results

results = wx.TextCtrl(panelAction, style = wx.TE_MULTILINE | wx.HSCROLL)

# Base Network for Class C IP Addresses has 3 components

# For class C addresses, the first 3 octets define the network i.e 127.0.0

# the last 8 bits define the host i.e. 0-255

# Thus I setup 3 spin controls one for each of the 4 network octets

# I also, set the default value to 127.0.0.0 for convenience

ipaRange = wx.SpinCtrl(panelAction, -1, '')

ipaRange.SetRange(0, 255)

ipaRange.SetValue(127)

ipbRange = wx.SpinCtrl(panelAction, -1, '')

ipbRange.SetRange(0, 255)

ipbRange.SetValue(0)

ipcRange = wx.SpinCtrl(panelAction, -1, '')

ipcRange.SetRange(0, 255)

ipcRange.SetValue(0)

ipdRange = wx.SpinCtrl(panelAction, -1, '')

ipdRange.SetRange(0, 255)

ipdRange.SetValue(1)

# Add a label for clarity

ipLabel = wx.StaticText(panelAction, label="IP Address: ")

# Next, I want to provide the user with the ability to set the port range

# they wish to scan. Maximum is 20 - 1025

portStart = wx.SpinCtrl(panelAction, -1, '')

portStart.SetRange(1, 1025)

portStart.SetValue(1)

portEnd = wx.SpinCtrl(panelAction, -1, '')

portEnd.SetRange(1, 1025)

portEnd.SetValue(5)

PortStartLabel = wx.StaticText(panelAction, label="Port Start: ")

PortEndLabel = wx.StaticText(panelAction, label="Port End: ")

# Now I create BoxSizer to automatically align the different components neatly

# First, I create a horizontal Box

# I'm adding the buttons, ip Range and Host Spin Controls

actionBox = wx.BoxSizer()

actionBox.Add(displayAll, proportion=0, flag=wx.LEFT|wx.CENTER, border=5)

actionBox.Add(scanButton, proportion=0, flag=wx.LEFT, border=5)

actionBox.Add(exitButton, proportion=0, flag=wx.LEFT, border=5)

actionBox.Add(ipLabel, proportion=0, flag=wx.LEFT|wx.CENTER, border=5)

actionBox.Add(ipaRange, proportion=0, flag=wx.LEFT, border=5)

actionBox.Add(ipbRange, proportion=0, flag=wx.LEFT, border=5)

actionBox.Add(ipcRange, proportion=0, flag=wx.LEFT, border=5)

actionBox.Add(ipdRange, proportion=0, flag=wx.LEFT, border=5)

actionBox.Add(PortStartLabel, proportion=0, flag=wx.LEFT|wx.CENTER, border=5)

actionBox.Add(portStart, proportion=0, flag=wx.LEFT, border=5)

actionBox.Add(PortEndLabel, proportion=0, flag=wx.LEFT|wx.CENTER, border=5)

actionBox.Add(portEnd, proportion=0, flag=wx.LEFT, border=5)

# Next I create a Vertical Box that I place the Horizontal Box components

# inside along with the results text area

vertBox = wx.BoxSizer(wx.VERTICAL)

vertBox.Add(actionBox, proportion=0, flag=wx.EXPAND | wx.ALL, border = 5)

vertBox.Add(results, proportion=1, flag=wx.EXPAND | wx.LEFT | wx.BOTTOM | wx.RIGHT, border=5)

# I'm adding a menu and status bar to the main window

mainWin.CreateStatusBar()

# Finally, I use the SetSizer function to automatically size the windows

# based on the definitions above

panelAction.SetSizer(vertBox)

# Display the main window

mainWin.Show()

# Enter the Applications Main Loop

# Awaiting User Actions

app.MainLoop

Now that you have reviewed the code, Figures 8.11 and 8.12 depict program execution. The only difference between the two figures is the setting of the Display All checkbox.