for /f "tokens=3" %%a in ('wmic os get caption ^| findstr Microsoft') do set wver=%%a

if %wver% equ 7 (
set key=33PXH-7Y6KF-2VJC9-XBBR8-HVTHH
)
if %wver% equ 10 (
set key=DCPHK-NFMTC-H88MJ-PFHPY-QJ4BJ
)

cscript %WINDIR%\system32\slmgr.vbs /skms #KMS서버의IP주소:1688#
cscript %WINDIR%\system32\slmgr.vbs /ipk %key%
cscript %WINDIR%\system32\slmgr.vbs /ato


위에 게시된 키들은 실제 KMS Client의 키이다.

https://docs.microsoft.com/ko-kr/windows-server/get-started/kmsclientkeys
참조