[NumLock]

Код:

procedure TForm1.Button1Click(Sender: TObject);
var
  i: Integer;
begin
  for i:=1 to 5 do
  begin
    ListBox1.Items.Add('i='+IntToStr(i));
    IdIcmpClient1.Host:='www.delphisources.ru';
    IdIcmpClient1.ReceiveTimeout:=5000;
    IdIcmpClient1.Ping;
  end;
end;

procedure TForm1.IdIcmpClient1Reply(ASender: TComponent;
  const AReplyStatus: TReplyStatus);
begin
  ListBox1.Items.Add('Reply:'+IntToStr(AReplyStatus.MsRoundTripTime));
  Application.ProcessMessages;
end;