Existing Customers

A KMS key is a Volume License Key that is used to establish an activation service that is hosted locally in your environment. After the service is established, you can activate your client and server computers by connecting to the KMS host computer. Computers activated through KMS must reactivate at least once every six months by connecting to the KMS host.

A KMS key can activate six KMS hosts with 10 activations per host. Each host can be used to activate an unlimited number of computers that are running Windows Server 2008, Windows Vista Business, or Windows Vista Enterprise. If you need more activations for your KMS key, you can call your Microsoft Activation Center to request an increase.

• Find the telephone number for your Microsoft Activation Center

• Download a document about MAK and KMS Volume License Keys and activation limits (DOC, 57.5 KB)

KMS keys can be obtained in the same ways you obtained Volume Activation 1.0 keys (that is, keys for Windows XP Professional and Windows Server 2003 R2):

• Go to the Volume Licensing Service Center (VLSC). KMS keys are available from the Existing Keys page

• Contact your Microsoft Activation Center.

If you are a Service Provider License Agreement (SPLA) customer, you will need to request keys by calling your Activation Center; the keys are not available through the VLSC.

A Multiple Activation Key (MAK) is a Volume License Key that activates your client and server computers by connecting them to a Microsoft activation server one time. After the computers are activated, no further communication with Microsoft is required.

There are two activation methods for MAKs:

1. MAK Independent Activation. Each computer is activated individually by connecting to Microsoft servers over the Internet or by telephone.

2. MAK Proxy Activation. By using the Volume Activation Management Tool (VAMT), you can activate multiple computers at the same time through a single connection to Microsoft servers over the Internet or phone.

Download the Volume Activation Management Tool

There are two ways to get a MAK:

1. Go to the Volume Licensing Service Center (VLSC).

   On the New MAK Keys page, find the agreement you want. Select the check boxes for each MAK you want to request, and then click Request MAK Key. Your request will be processed and the page will be updated to provide your MAKs. The next time you log on to the VLSC, these keys will be displayed on the Existing Keys page.

   Note: If you navigate away from this page before you click Request MAK Key, you will discard your selections.

2. Contact your Microsoft Activation Center.

   If you are a Service Provider License Agreement (SPLA) customer, you will need to request keys by calling your Activation Centers; the keys are not available through the VLSC.

MAKs allow a predetermined number of activations. This number depends on the type of agreement you have. The number of activations can be revised (at the request of the customer or by Microsoft) to accommodate your regular usage. If your existing MAK activation limit is inadequate for your deployment, please contact the Microsoft Activation Center.

• Find the telephone number for your Microsoft Activation Center

• Download a document about MAK and KMS Volume License Keys and activation limits (DOC, 57.5 KB)

Yes. Volume Licensing customers can use KMS keys, MAKs, or both to activate their computers.

Yes. MAKs and KMS keys are available per server product group and edition. The following table shows the details of the types of keys available. Windows Server 2008 keys are aligned with product group editions and there are more keys available; this may entail more planning and management until you are comfortable with the changes. For example, Windows Vista Volume License Keys worked for both Windows Vista Enterprise and Windows Vista Business.

Products Activated by MAK

MAKs for Windows Server 2008 must be used with specific server products. For example, if you purchase licenses for Windows Server 2008 Enterprise, you must use the MAK_B key.

Products Activated by KMS Key

KMS keys are hierarchical. For example, if you have licenses for Windows Server 2008 Datacenter and Standard editions, you should use the KMS key associated with Datacenter product (KMS_C key) to activate machines installed with Windows Server 2008 Datacenter as well as Windows Server 2008 Standard.

Yes. You can use a Windows Server 2008 computer as a KMS host. If you do this, you do not need to set up a host computer by using a Windows Vista KMS key.