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Can you help me with my software licensing question?

We need to build out a server running Windows 2008 R2 Standard that can allow up to 10 simultaneous RDP/Terminal Services connections and I'm a little confused about how the CAL licenses work. From one source I was told I needed 10 "server CALs" and an additional 10 "RDP CALs" (total of 20 CALs). From another, I was told I just needed the 10 "RDP CALs", which implicitly came with the server CAL. The Microsoft licensing website ( seems to support scenario #1, but it is still not real clear what those server CALs are needed for. Also, can we use the 2 "built-in" RDP clients, meaning we only need to purchase 8 CALs to reach a total of 10?

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marked as duplicate by Iain, Scott Pack, jscott, Ben Pilbrow, Zoredache Mar 9 '11 at 17:26

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

up vote 5 down vote accepted

You will need to purchase the 10 server CALs as well as the 10 RDP CALs.

The server CALs are needed so that the users are licensed to talk to the Windows 2008 R2 OS. If you already have Windows 2008 R2 CALs then you don't need to purchase more.

You can not use the default 2 admin RDP connections. Those are not RDP CALs as they are built in for remote admin use only, so you'll still need to purchase 10 RDP cals.

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Microsoft licensing is so complicated they actually have a certification for it.

Okay, here's the lowdown:

  • For each client connecting to a Windows Server (any kind of service), you need 1 CAL

  • In addition, to activate Terminal Server so that it can serve more than 2 RDP sessions, you need 1 TS CAL per client who wants to connect.

  • When you've applied TS CAL to your Terminal Server, the 2 'free' administrator RDP sessions get disabled. IOW, you cannot buy (N-2) TS CALs.

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Also you have a choice when buying Remote Desktop Services CALs (RDP). User based or device based, there is no "concurrent" session option as there is with Citrix XenApp. User based will mean a single user account can connect from anywhere, but it's tied to their account. Device based means every device that connects will take a license and not give it until unused for up to 90 days. In the end this almost always requires people to buy more Session Host CALs then they original planned for in order to have a buffer.

choosing a mode

about license types

how to manually get device based CALs back

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