ever needed to test open ports on your machine?

you can write a small utility for this purpose in Delphi, using sockects... here's my approach

use this code under you own risk, I present this article for educational purposes only, I take no responsability for the use of it

I'll put a link to the whole demo, here's the unit, I'm sure you can recreate the form and run this:

------- beggining of unit -----
Unit PortScanU;

Interface

Uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ScktComp;

Type
  TMainForm = Class(TForm)
    LblIPAddress: TLabel;
    IPAddressE: TEdit;
    lblScanRange: TLabel;
    MinPortE: TEdit;
    lblPorttoport: TLabel;
    MaxPortE: TEdit;
    StatusL: TLabel;
    ActivityLB: TListBox;
    StartBtn: TButton;
    WSsocket: TClientSocket;
    StopBtn: TButton;
    OpenOnlyCB: TCheckBox;
    Procedure StartBtnClick(Sender: TObject);
    Procedure WSsocketConnect(Sender: TObject; Socket: TCustomWinSocket);
    Procedure WSsocketError(Sender: TObject; Socket: TCustomWinSocket;
      ErrorEvent: TErrorEvent; Var ErrorCode: Integer);
    Procedure StopBtnClick(Sender: TObject);
    Procedure FormCreate(Sender: TObject);
  Private
    { Private declarations }
    PortX, MaxPort:Integer;
    IsRunning:Boolean;
    Procedure SetStuffOnOff(Const St:Boolean);
  Public
    { Public declarations }
  End;

Var
  MainForm: TMainForm;
Implementation

{$R *.dfm}

Procedure TMainForm.SetStuffOnOff(Const St:Boolean);
Begin
  IsRunning:=St;
  StopBtn.Enabled:=St;
  StartBtn.Enabled:=Not St;
  If Not (St) Then
  Begin
    ActivityLB.Items.Add('Done Scanning ' + IPAddressE.text);
    StatusL.Caption:='Status:'
  End
End;

Procedure TMainForm.StartBtnClick(Sender: TObject);
Begin
  ActivityLB.Items.Clear;
  PortX := StrToInt(MinPortE.text);
  MaxPort := StrToInt(MaxPortE.text);

  wsSocket.Address := IPAddressE.text;
  wsSocket.Port := PortX;
  wsSocket.Active := True;

  SetStuffOnOff(True);
  ActivityLB.Items.Add('Beginning scan: ' + IPAddressE.text)
End;

Procedure TMainForm.WSsocketConnect(Sender: TObject;
  Socket: TCustomWinSocket);
Begin
  //socket connection made
  //port must be open!
  ActivityLB.Items.Add('PORT: ' + inttostr(PortX) + '; OPEN!');

  //try next port...
  wsSocket.Active := False;
  PortX := PortX + 1;
  wsSocket.Port := PortX;
  StatusL.Caption:='Scanning port:['+IntToStr(PortX)+']';

  If (IsRunning) Then
    If (PortX > MaxPort) Then
      SetStuffOnOff(False)
    Else
      wsSocket.Active := True //test the new port
End;

Procedure TMainForm.WSsocketError(Sender: TObject; Socket: TCustomWinSocket;
  ErrorEvent: TErrorEvent; Var ErrorCode: Integer);
Begin
  //connection failed....
  ErrorCode:=0; //handle the error
  If Not (OpenOnlyCB.Checked) Then
    ActivityLB.Items.Add('Port: ' + inttostr(PortX) + '; Closed.');

  //try next port
  wsSocket.Active := False; //close it
  PortX := PortX + 1;       //new port to check
  wsSocket.Port := PortX;   //put the port in the socket
  StatusL.Caption:='Scanning port:['+IntToStr(PortX)+']';

  If (IsRunning) Then
    If (PortX > MaxPort) Then
      SetStuffOnOff(False)
    Else
      wsSocket.Active := True //test the new port
End;

Procedure TMainForm.StopBtnClick(Sender: TObject);
Begin
  SetStuffOnOff(False);
  wssocket.Active := False;
  ActivityLB.Items.Add('Stoped scan; port ' + inttostr(PortX) + '!')
End;

Procedure TMainForm.FormCreate(Sender: TObject);
Begin
  IsRunning := False
End;

End.
--------- end of unit ---------
as you can see, the idea is pretty easy...
- set the address
- set the port
- try to activate the socket
- and check if it went good
- next port, repeat steps

note:to test ports on your local machine you need to set
IPAddressE.Text:='localhost'

let me know of any bugs

oh, by the way, the source code of the article was formatted using my:
PAS 2 HTML converter

...keep up coding

EberSys