Windows Server and Remote Desktop Services Licensing Basics

The best sources of Windows Server licensing info are Microsoft's licensing datasheets and Product Terms. This doc lists the most important aspects of licensing on-premise installations of Windows Server at UW-Madison.


  • Windows Server uses the server/client licensing model. In the server/client licensing model, both servers and clients connecting to the servers must be licensed.
    • All UW System faculty, staff, and students are licensed for client access to Windows Server under the terms of our Microsoft campus agreement. This means that you only have to purchase Windows Server licenses unless you have external users.
  • Windows Remote Desktop Services (RDS) also uses the server/client licensing model.
    • RDS servers are licensed with Windows Server; if you own a Windows Server license you're licensed to use an RDS server on the same machine.
    • RDS clients are not licensed, so if you want to use RDS, you have to purchase RDS user or device client access licenses (CALs) or external connector licenses.

Windows Server Editions

  • Standard: Fully licensing the server licenses you to run 2 VMs. You can fully license the server again to add an additional 2 VMs and you can repeat this process as many times as you like.
  • Datacenter: Fully licensing the server licenses to run unlimited VMs.
  • In addition, these technologies are available in Datacenter but not in Standard:
    • Storage features including Storage Spaces Direct and Storage Replica
    • Shielded Virtual Machines
    • Networking stack

Software Assurance


Determining What Licenses To Buy

  • Windows Servers

    • Windows Server licensing always references the physical cores (not processors, not CPUs, not virtual cores) of the machines being licensed.
    • Each of the Windows Server license SKUs available for purchase in the catalog licenses two cores in one physical server.
    • Microsoft enforces a minimum purchase of eight of the license SKUs per server, which licenses up to 16 cores in one machine. More cores would require additional purchases.
    • If you have Windows Server VMs running on multiple physical hosts, all of the cores in all of the physical hosts must be licensed.
      • However, if you can limit Windows Server VMs to specific hosts (using VMWare's VM-Host Affinity Rule or similar techology), you would only have to license the cores in the hosts to which the servers are restricted.
    • CALs - Since UW-Madison is already licensed for Windows Server CALs, you generally don't need to purchase CALs. If you want to license access by users unaffiliated with UW-Madison, you would buy an External Connector license to license one server for an unlimited number of external users.
    • Licensing by virtual machine - this is a new option for licensing that Microsoft now offers as of October 2022. You can find full information about this program at this link:
  • RDS

    • CALs are required for each device or user. They are required regardless of the technology used to remotely access the server.
    • CALs are required for any device or user accessing any Remote Desktop Service, including but not limited to Remote Desktop Gateway, Remote Desktop Web Access, Remote Desktop Connection Broker, Remote Desktop Session Host, and/or Remote Desktop Virtualization Host.
    • One device CAL is required for each unique device accessing the server, not for the total number of devices at a given time.
    • One user CAL is required for each unique, named user accessing the server, not for the total number of users at a given time.
    • External Connector Licenses...
      • license access to Remote Desktop Services on one server by an unlimited number of users not employed by UW-Madison.
      • can be used to license students.

Windows Server and Remote Desktop Services licenses can be purchased from the Software Order Form.

Keywordswindows server license licensing 2019 2016 2012 2008 2008r2 r2 core VM virtual machine host physical   Doc ID97311
OwnerNick R.GroupDoIT Help Desk
Created2020-01-24 09:16:21Updated2024-01-19 17:02:18
SitesDoIT Help Desk
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