Key Management Service (KMS) is a feature provided by Microsoft for activating software deployed in bulk across many machines in an organization. KMS uses a client-server topology to active systems. KMS client machines connect to a KMS host, called the KMS server, for activation.
KMS activation is used to activate volume licensed versions of Microsoft Windows and Office products. It’s designed for mid-to-large sized organizations that have a Volume Licensing agreement with Microsoft. KMS allows IT administrators to complete activations on their local network, eliminating the need for individual computers to connect to Microsoft for product activation. This reduces the administrative overhead and makes it easier to deploy and manage software assets.
How KMS Activation Works
The KMS activation process works as follows:
- A KMS host key is installed on a system that will act as the KMS server. The KMS host key is unique to the organization and maps to their specific licensing agreement.
- The KMS host software is installed and activated on the KMS server using the KMS host key. The KMS server does not need to be a dedicated system, but can be any Windows server on the network.
- Computers that need to be activated, known as KMS clients, are configured with a generic volume license key (GVLK). The GVLK is built into the Windows and Office installation media and is the same for all customers.
- When a KMS client joins the network, it automatically searches for the KMS server by sending out DNS queries for specific SRV records.
- Upon finding the KMS server, the client sends an activation request to the server. The request includes information about the software that needs activation.
- The KMS server checks that the GVLK sent by the client matches its KMS host key and that the activation threshold is met. The default activation threshold is 25 computers for Windows Server and 5 for Windows desktop systems.
- If the checks pass, the KMS server sends back an activation response to the client, activating the software. The activation is valid for 180 days.
- The client will automatically attempt to renew its activation every 7 days. As long as the KMS server remains available, the activation will be transparently renewed without any user interaction.
Benefits of KMS Activation
There are several benefits to using KMS for volume activation in an enterprise:
- Reduced Internet Connectivity Requirements: Since activation takes place within the local network, individual computers do not need to connect to Microsoft’s activation servers. This is useful for secure environments with limited internet access.
- Simplified Deployment: With KMS, IT administrators can use a single volume license key (the GVLK) for installation. The actual activation process is automatic and transparent to the end user.
- Centralized Management: KMS provides a centralized solution for license activation. Administrators have a single point of control for monitoring and managing software activations.
- Scalability: KMS is designed to handle a large number of activation requests. A single KMS server can activate thousands of computers.
- Reduced Costs: KMS is available at no additional cost to customers with a Volume Licensing agreement. There are no additional fees for using KMS.
Considerations for Implementing KMS
While KMS provides a streamlined activation process, there are a few things to keep in mind:
- KMS Server Availability: KMS clients must be able to reach the KMS server to activate and renew their activation. If the KMS server becomes unavailable, clients will eventually enter a grace period and then become deactivated.
- Activation Thresholds: A minimum number of computers (25 for Windows Server, 5 for Windows desktop) must request activation from a KMS server before the server will begin activating clients.
- DNS Configuration: KMS clients find the KMS server by querying DNS. Proper DNS configuration is necessary for KMS to function correctly.
- Client Configuration: KMS clients must be configured with the GVLK and have the appropriate licensing information installed. This is typically done through volume license media or a custom image.
- Licensing Compliance: While KMS simplifies the activation process, it’s still important for organizations to ensure they are compliant with their Volume Licensing agreement. KMS does not enforce or manage license compliance.
Conclusion
KMS activation is a valuable tool for organizations deploying Microsoft software in volume. It simplifies the activation process, reduces internet connectivity requirements, and provides a centralized point of control. When properly implemented, KMS can significantly reduce the administrative overhead associated with software activation.
However, KMS is just one part of an overall software asset management strategy. Organizations must still ensure they have the appropriate licenses for their software and that they are complying with the terms of their licensing agreement. Used in conjunction with other tools and processes, KMS can help organizations efficiently manage their Microsoft software assets.