Insufficient counts after KMS host migration

For this new AD forest, I've been leveraging on someone else KMS service. As it grows bigger, time to setup its own KMS host. It's pretty straightforward to migrate KMS server. Plenty of step-by-step online like this. I have also manually updated the _vlmcs._tcp SRV record on DNS server.  And there is a problem. If you attempt to activate small number of new KMS clients after migration, it would report insufficient count. For KMS to work, you would need at least either 5 KMS servers or 25 KMS clients.  

So, I tried to re-activate existing machines by uninstalling existing KMS client key and re-installing it. The count level on the KMS host still won't jump and remain under 5. You can see the current count level by entering "slmgr -dlv" on the KMS host.

After going through all the slmgr options, I noticed an option to disable KMS host caching. Could it because the existing machines still activate on old KMS server? 

On a number of existing KMS client machines:

> slmgr -ckhc

> slmgr -ato

Hurry, the count is raised! New KMS clients are activated at once.

Activating Windows 8 and Windows Server 2012 on existing AD environment

As we putting new Windows 8 and Windows Server 2012 into existing AD environment, there are 2 things that need to be done. First, if you're still using Windows Server 2008 as KMS host, download and install the update 2757817. Otherwise, you'll see the following error when you activate KMS with the new key:

Error: 0xC004F050 The Software Licensing Service reported that the product key is invalid

Next, upgrade the existing key on the KMS host by running:

1. "slmgr /upk" to uninstall existing key, 
2. "slmgr /ipk xxxxx-xxxxx-xxxxx-xxxxx-xxxxx" to install new KMS key and;
3. "slmgr /ato" to activate the new key.
4. "slmgr /dlv" to verify the key has been successfully upgraded to support the new Windows 8. You should see "VOLUME_KMS_2012_C_channel" on the description.

For detailed step-by-step, check out this blog post.

KMS requirements

Microsoft Volume Licensing Activation comes in 2 forms: Multiple Activation Key (MAK) and Key Management Service (KMS). It is also well published in Microsoft website if you have at least 5 servers or 25 clients, you should go for KMS.

Now, we have about a dozen of servers in a particular network activated by KMS. Recently, I joined the first Win7 client to the domain and was unable to activate this client. Error: "The count reported by your KMS server is insufficient". Ops! I thought I already have more than 5 servers in this domain!?

A further check with Microsoft now confirms this:
KMS volume activation requires a minimum number of physical Windows clients: five (5) for Windows Server 2008, or twenty five(25) for Windows Vista. However, KMS does not differentiate between the two systems when counting the total number of clients. For example, a KMS host with a count of three (3) Windows Vista clients and two (2) Windows Server 2008 clients would activate the two (2) Windows Server 2008 clients because the cumulative count is five (5) clients. But KMS would not activate the three (3) Windows Vista computers until the total client count reached twenty-five (25). Each time a new machine contacts a KMSHOST, it is added to the count for thirty calendar (30) days, after which its record is deleted, similar to Time-To-Live (TTL) for Domain Name System (DNS) records.

Migrating KMS Host for Windows Activation

Two types of activation for Microsoft OS, MAK (Multiple Activation Key) and KMS (Key Management Service). The former activation is mainly used for less than 5 servers. If you use KMS, the first four hosts won't be activated until the fifth is activated. Earlier, we did a mistake of keying in the KMS host license key into some of our servers instead of the KMS client keys. As a result, multiple SRV of _VLMCS._tcp. appears on the DNS servers. Furthermore, the current KMS server is not supposed to have Internet access. Hence, we decided to migrate the KMS to another VM.

Note: If you just need to install a new KMS server, jump straight to step 5.

Steps to migrating the KMS:

1. Uninstall the KMS host key first by running the following command:

slmgr -upk

2. Then, install the default kms key by running the following command:

slmgr /ipk [KMS Client Setup Key]

The default KMS client setup keys for W2K8 R2 Enterprise is 489J6-VHDMP-X63PK-3K798-CPX3Y. As for the rest, the default KMS client keys can be found here.

3. Delete the old SRV record from the DNS:

Open DNS console:

Expand _tcp node under the domain.com. There will be a record _VLMCS. Delete this record.

4. The KMS server is uninstalled.

5. To install KMS on a new server, enter:

cscript C:\windows\system32\slmgr.vbs /ipk

then to activate the KMS host, enter:

cscript C:\windows\system32\slmgr.vbs /ato

6. After activation is complete, restart the Software Licensing Service by running "net stop sppsvc && net start sppsvc"

7. Verify that the record is created for the new server in the DNS.

To verify that the KMS host is configured correctly, you can check the KMS count to see if it is increasing. Run slmgr.vbs /dli on the KMS host to obtain the current KMS count. You can also check the Key Management Service log in the Applications and Services Logs folder for 12290 events, which records activation requests from KMS clients. Each event displays the name of the computer and the time-stamp of an individual activation request.
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Windows 7 and Server 2008 KMS Client Keys
Windows 7 Professional - FJ82H-XT6CR-J8D7P-XQJJ2-GPDD4
Windows 7 Professional N - MRPKT-YTG23-K7D7T-X2JMM-QY7MG
Windows 7 Enterprise - 33PXH-7Y6KF-2VJC9-XBBR8-HVTHH
Windows 7 Enterprise N - YDRBP-3D83W-TY26F-D46B2-XCKRJ
Windows 7 Enterprise E - C29WB-22CC8-VJ326-GHFJW-H9DH4

Windows Server 2008 R2 HPC Edition - FKJQ8-TMCVP-FRMR7-4WR42-3JCD7
Windows Server 2008 R2 Datacenter - 74YFP-3QFB3-KQT8W-PMXWJ-7M648
Windows Server 2008 R2 Enterprise - 489J6-VHDMP-X63PK-3K798-CPX3Y
Windows Server 2008 R2 for Itanium-Based Systems - GT63C-RJFQ3-4GMB6-BRFB9-CB83V
Windows Server 2008 R2 Standard - YC6KT-GKW9T-YTKYR-T4X34-R7VHC
Windows Web Server 2008 R2 - 6TPJF-RBVHG-WBW2R-86QPH-6RTM4