[megaloman]

Можно без setlocal enabledelayedexpansion

Код:

@Echo Off
cls
	set /A min=1, max=20
	For /L %%i In (1,1,10) Do (
		call :gen
		call echo Attempt %%i n=%%r10%%
		Call ping -n %%r10%% 127.0.0.1 >nul
	)
pause
Exit /B

:gen
	set /a r10=min+(max-min+1)*%random%/32768
exit /b

Код:

@Echo Off
cls
	set /A min=1, max=20
	For /L %%i In (1,1,10) Do call :gen %%i
pause
Exit /B

:gen
	set /a r10=min+(max-min+1)*%random%/32768
	echo Attempt %1  n=%r10%
	ping -n %r10% 127.0.0.1 >nul
exit /b