procedure TForm1.Button1Click(Sender: TObject);
type
 InAddr = Array[0..10] of PInAddr;
 TInAddr = ^InAddr;
var
 Host: PHostEnt;
 pPtr: TInAddr;
 Buffer: Array[0..63] of char;
 i: Integer;
 Socket: TWSAData;
begin
  ListBox1.Clear;
  WSAStartup( $101, Socket );
  GetHostName( Buffer, SizeOf( Buffer ) );
  Host := GetHostByName( buffer );
  if Host = nil then Exit;
  pPtr := TInAddr( Host^.h_addr_list );
  i := 0;
  while pPtr^[i] <> nil do
  begin
     ListBox1.Items.Add( inet_ntoa( pPtr^[i]^ ) );
     Inc( i );
  end;
  WSACleanup;
end;