KMS Activation High Level Overview

Hello, folks!

This blog is aimed to provide a high level overview of the Key Management Server (KMS) technology.

You may have found a lot of dispersed activation information available elsewhere on the Internet, but I’m going to try and pull it all together for you in a concise format that I hope you’ll find is easy to digest.

First, make sure you can meet the initial KMS requirements for deployment:

1. By default, the following ports are required for activation:

  • 80
  • 443
  • 1688

2. Activation requests are fulfilled after meeting the corresponding product count minimum.

  • Workstation OS: 25
  • Server OS: 5
  • Office: 5

3. Activated products require a connection to the corporate network at least once every 180 days.

Next, let’s take a look at the basic KMS infrastructure:


KMS host machines distribute activation signals, whereas KMS clients are machines that needs to be activated (they can be either servers or workstations).

KMS host or client machine roles can be distinguished through the type of keys used. KMS Host Key directs host machine to create a SRV record (_VLMCS) in DNS. To obtain a host key, visit here. KMS Client Key directs client machines to look for a SRV record in DNS which points to the KMS host machine. Obtain a client setup key here.


Office Volume Activation:

The Microsoft Office Volume License Pack is required on Office KMS host. Obtain the license packs here:

Microsoft Office 2013 Volume License Pack
Microsoft Office 2010 KMS Host License Pack

After installing the license pack, it will prompt you to install Office KMS host key. If nothing goes wrong with that process, your Office KMS should be all set.


For your reference, here are TechNet guides for setting up Office KMS activation.

Prepare and set up the Office 2013 KMS host
Set Up an Office 2010 KMS Host


Additional Tool:

Volume Activation Management Tool (VAMT) is a free utility that is very helpful to apply product keys and manage activation status.

Download and Installation

  • This tool is part of the Windows Assessment and Deployment Kit (ADK), available here.
  • The latest version of VAMT is 3.1 as of this writing, and supports OS’s up to Windows 8.1 and Server 2012 R2.
  • VAMT Requirements:
  • The .NET Framework is required and is installed automatically with the ADK.
  • SQL Server Express is required and you should choose to install it as a feature when going through the ADK setup wizard.
  • More Information:

There are a couple of best practices to keep in mind when using KMS, and a few common mistakes you’ll want to avoid.


Best Practices

  1. KMS OS host and KMS office host can be the same server
  2. Keep roaming users on MAK key (roaming users are those who would not be connected to the company domain at least once every 180 days)


Common KMS Mistakes

  1. Installing a KMS host key on clients.
  2. The KMS host key does not match the host machine OS
  3. The latest patches have not been applied to the host machine.


And now on to some common KMS commands you’ll want to keep on tap.

Install a product key on the KMS Host

  • slmgr /ipk <KMS Host Key>

Activate a product key:

  • slmgr /ato

Display OS License Information:

  • slmgr /dlv

Display All License Information (including office activation status):

  • slmgr /dlv all

Note: The popup window for this command doesn’t scroll, so run the following command to write the output to a text file.

cscript.exe c:\windows\system32\slmgr.vbs /dlv all > c:\temp\dlv.txt

I hope this has been a helpful high-level overview of our KMS technology and wish you all the best!

Kind regards,
Sophie Fei Xu
Support Escalation Engineer
Microsoft Global Business Support