急！急！急！如何在DELPHI程序中获取动态IP动址？？？？(50分)

急！急！急！如何在DELPHI程序中获取动态IP动址？？？？

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
Winsock, StdCtrls, ExtCtrls, Menus ,clipbrd;

type
TForm1 = class(TForm)
Timer1: TTimer;
PopupMenu1: TPopupMenu;
Exit1: TMenuItem;
Label1: TLabel;
Copy1: TMenuItem;
procedure FormCreate(Sender: TObject);
procedure Timer1Timer(Sender: TObject);
procedure Exit1Click(Sender: TObject);
procedure formmousedown(sender: tobject; button: tmousebutton;
shift: tshiftstate; x, y: integer);
procedure Edit1StartDrag(Sender: TObject; var DragObject: TDragObject);
procedure Copy1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.DFM}

// returns ISP assigned IP
function HostName : string;
var
Buffer : array [0..63] of char;
GInitData : TWSADATA;
begin
WSAStartup($101, GInitData);
Result := '';
GetHostName(Buffer, SizeOf(Buffer));
Result := StrPas(Buffer);
WSACleanup;
end;

function LocalIP : string;
type
TaPInAddr = array [0..10] of PInAddr;
PaPInAddr = ^TaPInAddr;
var
phe : PHostEnt;
pptr : PaPInAddr;
Buffer : array [0..63] of char;
I : Integer;
GInitData : TWSADATA;

begin
WSAStartup($101, GInitData);
Result := '';
GetHostName(Buffer, SizeOf(Buffer));
phe :=GetHostByName(buffer);
if phe = nil then Exit;
pptr := PaPInAddr(Phe^.h_addr_list);
I := 0;
while pptr^ <> nil do begin
result:=StrPas(inet_ntoa(pptr^^));
Inc(I);
end;
WSACleanup;
end;

{subject : moving forms (and other twincontrols) without using the caption-bar}

procedure tForm1.formmousedown(sender: tobject; button: tmousebutton;
shift: tshiftstate; x, y: integer);
const
sc_dragmove = $f012;
begin
releasecapture;
twincontrol(application.mainform).perform(wm_syscommand,sc_dragmove, 0);
end;

procedure TForm1.FormCreate(Sender: TObject);
var
FullRgn, ClientRgn, ButtonRgn: THandle;
Margin, X, Y: Integer;
begin
top:=screen.Height-50;
left:=screen.width-120;
height:=Label1.Height;
width:=Label1.width;
Margin := (Width - ClientWidth) div 2;
FullRgn := CreateRectRgn(0, 0, Width, Height);
X := Margin;
Y := Height - ClientHeight - Margin;
ClientRgn := CreateRectRgn(X, Y, X + ClientWidth, Y + ClientHeight);
CombineRgn(FullRgn, FullRgn, ClientRgn, RGN_DIFF);
X := X + Label1.Left;
Y := Y + Label1.Top;
ButtonRgn := CreateRectRgn(X, Y, X + Label1.Width, Y + Label1.Height);
CombineRgn(FullRgn, FullRgn, ButtonRgn, RGN_OR);
SetWindowRgn(Handle, FullRgn, True);
//Hide Taskbar Icon
ShowWindow( Application.Handle, SW_HIDE );
SetWindowLong( Application.Handle, GWL_EXSTYLE,
GetWindowLong(Application.Handle, GWL_EXSTYLE) or
WS_EX_TOOLWINDOW and not WS_EX_APPWINDOW);
ShowWindow( Application.Handle, SW_SHOW );
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
Timer1.interval:=1000*100;
Label1.Caption:='IP: '+LocalIP + #13#10
+ 'HostName: '+HostName;
end;

procedure TForm1.Exit1Click(Sender: TObject);
begin
application.terminate;
end;

procedure TForm1.Edit1StartDrag(Sender: TObject;
var DragObject: TDragObject);
const
sc_dragmove = $f012;
begin
releasecapture;
twincontrol(application.mainform).perform(wm_syscommand,sc_dragmove, 0);

end;

procedure TForm1.Copy1Click(Sender: TObject);
begin
Clipboard.SetTextBuf(Pchar(copy(Label1.caption,0,255)));
end;

end.
不但有IP，连主机名都有了。

弧岛师傅，是否能显示internet公用的动态IP 地址呢？

如果是局域网内部机器查询对外IP就麻烦多了。。
我试了很久，
可以用SocketClient和SocketServer来实现取得。

能具体点吗？？？
为什么有的网站一登录就显示IP？？

怎样用SocketClient和SocketServer来实现取得？能具体点吗