A multi-purpose enterprise server is the best candidate for KMS Host since the service is relatively lightweight. Installing the KMS Host (Server) on a machine is simply a product key that gets activated on the computer which initializes the Software Protection Service to listen on port 1688 for license activation requests.

Windows 2008 SP2 (and later) now updates the KMS count regardless of machine type, virtual or physical.

Apparently the KMS Host in Windows 2008 prior to SP2 (and Windows 2008 R2) didn’t update the activated client count when activating virtual machines.

Microsoft Office products are activated with a special KMS version & license key specific to Office.

Running slmgr.vbs /dli on the KMS Host provides the KMS activation count (a count of -1 means no clients have been activated).

Also, KMS doesn’t activate Windows servers until at least 5 different Windows servers have connected to KMS.

KMS doesn’t activate Windows workstations until at least 25 different Windows workstations have connected to KMS.

If the Windows license isn’t re-activated by a KMS server within 180 days (6 months), it shifts into a 30 day grace period after which it enters reduced functionality mode (retail only) or notification mode (where the user is notified regularly to re-activate) and continues to attempt a KMS connection every 2 hours until activated. Once activated by KMS, the KMS client communicates with the KMS server every 7 days to renew its activation as well as resetting the license counter to 0. The KMS client then initializes a connection to port 1688 on the KMS server.īy default, a Windows installation’s license is configured with a grace period of 30 days plus 2 “rearms” ( slmgr.vbs /rearm) for a total of 90 days to activate. The DNS query response includes the KMS server hostname and port number (1688). The KMS client discovers the KMS server by performing a DNS query for the KMS SRV record in DNS.ĭNS: Standard query SRV _vlmcs._ĭNS: standard query response SRV (addr 10.10.10.11) KMS supported clients include Windows Server 2008, Windows Server 2008 R2, Windows Vista, & Windows 7. Every KMS supported Windows version automatically communicates with the KMS server to activate Windows and manage the activation key (configuring the Windows OS with a KMS key forces it to find a KMS Host and get activation from it). KMS shifts the activation requirement to a single machine which is activated with a special KMS Host (server) key.

Starting with Windows Server 2008 & Windows Vista, Microsoft switched to an online activation system where every Windows OS requires activation. The Microsoft Key Management Server (KMS) is part of the Microsoft Volume Activation 2.0 solution managing Windows OS activation keys and performs activation for supported clients automatically.

Windows server 2019 standard kms key