KMS - What clients are licensed?

We have been running KMS for a while now and I am curious what clients are currently using this licensing method. I can easily pull the event logs from the server and comma delimited parse them in Excel, but you may have a client that hasn't checked in since the last log was archived. Something that may go hand in hand with this is at least figuring out how many licenses have been given out and how many are remaining in the host key.

Does anyone know if a good way to get the KMS server to tell you what, or how many unique, clients are using the KMS host licensing method?

KMS is by design stateless. The documents stated pretty clearly that there is no reporting capabilities, which means you're on your own for making one. You're already doing everything you can. The next step is to make a long term archive of event-logs so you can get longer timescales beyond what the server running KMS keeps.

Honestly, KMS is the most convenient way to license large number of computer, but the buck stops right there. You can pull statistics from it using cscript slmgr.vbs /dli; but the licensed count will never exceed twice the minimum to activate a particular license (ie Win 7 takes 25 to activate, so the count will never go over 50). It doesn't keep track of more than double the minimum, so it will only keep track of the most recent number.

Pulling the client information from the event log is the easiest centralized way to see what's activated. You can also use the Volume Activate Management Tool (VAMT, from the Windows AIK) meant for activating clients with MAK keys, it can also report the client status from KMS clients (however it has to contact the client and get the information directly from them; it doesn't talk to the KMS server).

Hopefully MS realizes the frustration they're putting everyone through and releases a better KMS server some day... This stuff ain't rocket science and you're not the first to stumble on it.

The Volume Activation Management Tool v3.1 has been released and it now includes several reports including how many clients of each type (MAK, KMS) have been activated. You can read an overview of the tool on TechNet at http://technet.microsoft.com/en-us/library/hh824953.aspx