checking PORT availability

[manofprayer]

Is there any way for me to check for a port setting before assigning it?

Of course when another application is using the port, and I want to use the same port, of course there would be conflict.

Is there anyway for me to be able to check the port avaiability before the system decides to use it?

*thank you*

[harsoni]

SUMMARY
This article describes how to monitor whether a TCI/IP port is in use.



MORE INFORMATION
There are times when it is necessary to know or monitor whether a port is in use. The following sample demonstrates how this is done.



Create a new Standard EXE project. Form1 is created by default.


Add 1 Timer, 2 Labels, 1 Listbox, 1 TextBox and 2 CommandButton controls to Form1. Position Label1 above Text1 and Label2 above List1.


Set the Sorted property of List1 to True.


Add the following code to the General Declarations section of Form1:

Option Explicit

Dim MySock As Object
Const PortsChecked = 200

Private Sub Command1_Click()
Timer1.Enabled = True
Timer1.Interval = 1000
End Sub

Private Sub Command2_Click()
Timer1.Interval = 0
Timer1.Enabled = False
End Sub

Private Sub Timer1_Timer()
Dim X As Integer

List1.Clear
For X = 1 To PortsChecked
DoEvents
Text1.Text = X
Set MySock = CreateObject("MSWinsock.Winsock.1")
MySock.LocalPort = X
On Error Resume Next
MySock.Listen ' If we get an error, the port is busy.
If Err.Number = 10048 Then
List1.AddItem X ' Log Active port # to list box.
Err.Number = 0
End If

MySock.Close
Set MySock = Nothing
Next X
End Sub

Private Sub Form_Load()
Label1.Caption = "Checking Port #"
Label2.Caption = "Ports In Use"
Command1.Caption = "Start"
Command2.Caption = "End"
Text1.Locked = True
End Sub



Run the program. If, for example, you have an active DCOM connection, you should see 135 displayed in the ListBox.

To change the number of ports checked, modify the constant PortsChecked. To change the amount of time between samples modify the constant TimerInt.

CODE FROM MSDN...

Sonia