VB.NET Port Scanner [TUT]

[Fragma]

Note: I take no credit for the coding of this port scanner..
Credits go to David Kramer for posting it on Code Project

Ok so first off create a new Windows Application Form
You will need to add:

- TextBox X2
- ListBox X2
- Button X2
- Labels
- Timer


Add a label next to TextBox1 saying 'Host:'
And add 1 next to TextBox2 saying 'Port:'
Change the text on Button1 to 'start'
Change Button2 to 'stop'
Add a label for ListBox1 saying 'Ports being scanned:'
Add 1 for ListBox2 saying 'Open ports:'

----------------------------------------------------

Ok now for the coding...

First off declare the variables

Code:

Dim host As String
Dim port As Integer
Dim counter As Integer

Add the following to Form_load

Code:

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Button2.Enabled = False
        TextBox2.Text = "0"
        'set counter explained before to 0
        counter = 0
    End Sub

Add the following to Timer_tick

Code:

Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
      'Set the host and port and counter
        counter = counter + 1 'counter is for the timer
        TextBox2.Text = counter
        host = TextBox1.Text
        port = TextBox2.Text
        ' Next part creates a socket to try and connect on with the given user information.
    
        Dim hostadd As System.Net.IPAddress = System.Net.Dns.GetHostEntry(host).AddressList(0)
        Dim EPhost As New System.Net.IPEndPoint(hostadd, port)
        Dim s As New System.Net.Sockets.Socket(System.Net.Sockets.AddressFamily.InterNetwork, _
        System.Net.Sockets.SocketType.Stream, System.Net.Sockets.ProtocolType.Tcp)
        Try
            s.Connect(EPhost)
        Catch
        End Try
        If Not s.Connected Then
            ListBox1.Items.Add("Port " + port.ToString + " is not open")
        Else
            ListBox1.Items.Add("Port " + port.ToString + " is open")
            ListBox2.Items.Add(port.ToString)
        End If
        Label3.Text = "Open Ports: " + ListBox2.Items.Count.ToString
    End Sub

Add the following to the Start button_click

Code:

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        ListBox1.Items.Add("Scanning: " + TextBox1.Text)
        ListBox1.Items.Add("-------------------")
        Button2.Enabled = True
        Button1.Enabled = False
        Timer1.Enabled = True
        Timer1.Start()
    End Sub

Add the following to Button2_click (stop)

Code:

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        'stop button
        Timer1.Stop()
        Timer1.Enabled = False
        Button1.Enabled = True
        Button2.Enabled = False
    End Sub

Hope this helps.