i would like to you as i am little bit confused.... can i apply server 2012 std. kms to my existing KMS of Server 2008 R2 Enterprise. if yes, then how can i achieve this. if no, then what are your suggestion As i have windows Server 2012 std machines running with no license, i have to install license for Server 2012 std.

Hello Imran, Check this article hope it will help you somehow. Also remember, The CAL (Client Access License) accessing the instance of Windows Server must be equivalent or higher in version than the server being accessed. You will need a Windows Server 2012 CAL to access a Windows Server 2012 instance and 2008 CALs are no more useful. Still you have a doubt about OS Licensing: For licensing questions, I suggest contact Microsoft Licensing Center for detailed explanation. http://www.microsoft.com/licensing/contact-us.aspx please call 1-800-426-9400 (select option 4), Monday through Friday, 6:00 A.M. to 5:30 P.M. (PST) to speak directly to a Microsoft licensing specialist. Worldwide customers can use the Guide to Worldwide Microsoft Licensing Sites http://www.microsoft.com/licensing/index/worldwide.asp to find contact information in their locationsRegards, Ravikumar P

Hello Imran, Check this article hope it will help you somehow. Also remember, The CAL (Client Access License) accessing the instance of Windows Server must be equivalent or higher in version than the server being accessed. You will need a Windows Server 2012 CAL to access a Windows Server 2012 instance and 2008 CALs are no more useful. Still you have a doubt about OS Licensing: For licensing questions, I suggest contact Microsoft Licensing Center for detailed explanation. http://www.microsoft.com/licensing/contact-us.aspx please call 1-800-426-9400 (select option 4), Monday through Friday, 6:00 A.M. to 5:30 P.M. (PST) to speak directly to a Microsoft licensing specialist. Worldwide customers can use the Guide to Worldwide Microsoft Licensing Sites http://www.microsoft.com/licensing/index/worldwide.asp to find contact information in their locationsRegards, Ravikumar P