IP verification in batch script - first match by findstr, secondly verify by for loops (only using windows built in functinallity?

Question

This is a question for the batch pro\'s i guess. Seems a lot of people do stumble over IP veriffication while batching, while just using windows built in functinallity, but

Answer 1

Basic structure for ip validation. Adapt as needed

@echo off
    setlocal enableextensions enabledelayedexpansion

    rem try some ip addresses 
    for %%i in ("1.1.1.1" "0.1.1.1" "250.1024.1.1" "10.0.2.1" "something" "" ) do (

        echo --------------------------------------------

        rem call with a variable to get return value
        call :validateIP %%~i ret 
        echo %%~i : return value : !ret! 

        rem call with or without variable to get errorlevel
        call :validateIP %%~i  && echo %%i is valid || echo %%i is invalid

    )   

    exit /b 

:validateIP ipAddress [returnVariable]
    rem prepare environment
    setlocal 

    rem asume failure in tests : 0=pass 1=fail : same for errorlevel
    set "_return=1"

    rem test if address conforms to ip address structure
    echo %~1^| findstr /b /e /r "[0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*" >nul

    rem if it conforms to structure, test each octet for rage values
    if not errorlevel 1 for /f "tokens=1-4 delims=." %%a in ("%~1") do (
        if %%a gtr 0 if %%a lss 255 if %%b leq 255 if %%c leq 255 if %%d gtr 0 if %%d leq 254 set "_return=0"
    )

:endValidateIP
    rem clean and return data/errorlevel to caller
    endlocal & ( if not "%~2"=="" set "%~2=%_return%" ) & exit /b %_return%