Key Management Service (KMS) is a technology used by Microsoft for volume licensing of its products․ It allows organizations to activate Windows and Office products on multiple computers within a network without having to contact Microsoft directly for each activation․ This article will dive deep into the intricacies of KMS auto licensing and activation cycles, providing a comprehensive understanding of how it works․ The KMS Server and Client Model KMS utilizes a client-server model for activation․ A designated server, called the KMS host, is installed on the network and acts as the central licensing authority․ Client computers, such as workstations or servers running Windows or Office, connect to this host for activation․ Activation and Renewal Cycles The KMS activation process involves a series of steps⁚ Client Request⁚ A KMS client computer initiates an activation request to the KMS host․ KMS Host Verification⁚ The KMS host verifies the client's license and checks if the minimum activation threshold has been met․ Activation Grant⁚ If the verification is successful, the KMS host grants a temporary activation to the client, typically for a period of 180 days․ Renewal Process⁚ Before the activation period expires, the client will automatically attempt to renew its activation with the KMS host․ This process repeats every seven days․ Minimum Activation Threshold A crucial aspect of KMS is the minimum activation threshold․ For each product version, there is a minimum number of client computers that need to be activated on the KMS server before it can grant activation to other clients․ This threshold ensures that KMS is only used for legitimate volume licenses․ For example, Windows 10 requires a minimum of 25 client activations․ KMS Client Setup Keys (GVLK) KMS client setup keys, also known as Generic Volume License Keys (GVLK), are specific keys used to redirect Windows clients to the KMS server for activation․ These keys are different from the KMS host keys used on th