dism.exe /online /enable-feature /featurename:NetFX3 /all /Source:D:\sources\sxs /LimitAccess D:\ in this case is the path to the Windows Server 2012 installation media.
dism.exe /online /enable-feature /featurename:NetFX3 /all /Source:D:\sources\sxs /LimitAccess D:\ in this case is the path to the Windows Server 2012 installation media.