The code below uses the WinSock unit to lookup your local IP number. Simply call the function LocalIP - it will return your IP as a string.
In a LAN, it will return your local IP number, e.g. 192.168.100.25, not your external IP number.
If you run through NAT then your public address can only be told by someone else like: http://www.myip.dk/
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, WinSock;
type
TForm1 = class(TForm)
Label1 : TLabel;
Button1: TButton;
Memo1 : TMemo;
procedure FormCreate(Sender: TObject);
private
{ private declarations }
public
{ public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
function LocalIP : String;
type
TArrayPInAddr = array [0..10] of PInAddr;
PArrayPInAddr = ^ TArrayPInAddr;
var
phe : PHostEnt;
pptr : PArrayPInAddr;
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
begin
exit
end;
pptr := PArrayPInAddr(phe^.h_addr_list);
i := 0;
while pptr^[i]<>nil do
begin
result := StrPas(inet_ntoa(pptr^[i]^));
Inc(i);
end;
WSACleanup;
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
ShowMessage ('Your computer''s IP address is: '+LocalIP);
end;
end.