Implementation of Windows Server CAL Licenses

Introduction

User management and proper license administration are ongoing challenges for IT managers in SMEs. In Windows server environments, understanding and properly implementing CAL licenses (Client Access Licenses) is essential to maintain software license compliance and ensure smooth network operations. In this blog, we explain what Windows Server CALs are, how to plan their implementation, and how to carry it out step-by-step. Additionally, we provide a practical example and compare Microsoft license management with Adobe Creative Cloud license administration.

What Are Windows Server CAL Licenses and Why Do They Matter?

A Windows Server CAL is a Client Access License that grants legal rights to a user or device to access Windows Server services. In other words, when you purchase a Windows Server license for your server, that license allows you to install the server software, but it does not automatically cover the clients that connect to that server. To legally allow each user or device to access the server's resources (e.g., domain authentication, shared files, network printers, business applications), a CAL is required for each one.

Why are these licenses important? Because they ensure that your environment is properly licensed according to Microsoft’s terms. Allowing client access without the proper CALs constitutes a violation of the license agreement. In the event of an audit, Microsoft may require the immediate purchase of the missing CALs and impose penalties. Technically, Windows Server does not restrict the number of client connections, but legally, you need a CAL for every user or device that connects.

Another important aspect is version compatibility: CALs are tied to the version of the server. A CAL grants access to the same version of Windows Server for which it was issued (and to earlier versions), but not to later versions. For example, Windows Server 2019 CALs allow access to 2019 or earlier servers, but not to a 2022 server; for that, 2022 CALs would be required. This is a crucial point if you’re planning to upgrade your server to a newer version.

Implementation of Windows Server CAL LicensingImplementation of Windows Server CAL Licensing

Types of CAL Licenses: User vs Device

Microsoft offers two main types of CALs for Windows Server: User CAL and Device CAL. Both serve the same purpose (authorizing client access to the server), but they differ in who or what the license is assigned to.

User CALs

A User CAL grants access rights to an individual user to access the server, regardless of the devices they use. The license is assigned to the person (for example, to Juan Pérez’s account in Active Directory) and allows Juan to connect from his desktop, laptop, or any other device without requiring additional licenses for each device.

This model is ideal when employees use multiple devices for work or if the company has a BYOD (Bring Your Own Device) policy. For example, if an employee uses both an office PC and a laptop to connect to the server, one User CAL will cover both devices (1 user = 1 CAL). In contrast, Device CALs would require one license per machine. User CALs are more efficient in environments where the total number of devices exceeds the number of users, as fewer licenses (one per user) are needed to cover all access.

Device CALs

A Device CAL grants server access rights to a specific device (PC, laptop, tablet, etc.), regardless of how many different users operate that device. The license is assigned to the machine.

This option is suitable when multiple users share a few physical devices. For instance, if you have a shared PC used in shifts by several employees, one Device CAL assigned to that computer will allow all users to access the server (1 device = 1 CAL), regardless of how many individuals use it during the day. Device CALs are cost-effective for businesses with more employees than devices—like shift-based workstations, kiosks, or shared computers in a workshop—because with fewer licenses (one per device), you can cover all users who use that machine.

It’s possible to purchase both types of CALs within the same organization, depending on the needs of each area (for example, User CALs for office employees with multiple devices, and Device CALs for shared factory PCs). Just make sure to keep clear records to cover all access points without duplicating or overlooking licenses.

Visual tip: A comparative infographic would be helpful to show one user with multiple devices vs. multiple users sharing a single device, illustrating how User and Device CALs apply in each scenario.

User or Device? How to Choose the Right CAL Type

Factors to consider when deciding:

  • Usage profile (users vs. devices): Assess how many unique users and how many different devices will connect, and how they’ll connect. If each employee uses multiple devices (e.g., desktop and laptop), User CALs are likely the better option. If multiple employees share the same equipment (shift workstations, kiosks, etc.), then Device CALs are more appropriate. Analyzing who uses what and how many devices per person is the most important factor for choosing correctly.
  • Growth and turnover: Consider near-future expansion. If you're planning to add more staff or workstations, purchase enough CALs to avoid shortages. Also consider employee turnover: User CALs can be reassigned when someone leaves and another person takes over, while Device CALs are tied to the physical device (so adding more devices will require more licenses). If possible, keep a few spare licenses for unexpected needs.
  • Cost and optimal mix: Compare the total cost of each licensing model in your scenario. Sometimes the best solution is to mix CAL types for greater efficiency (e.g., assign User CALs to office staff with multiple devices, and Device CALs to shared workstations on the shop floor). The key is to cover all access needs using the fewest licenses, choosing the right type for each case.

Technical Implementation of CAL Licenses in Windows Server

Once you've defined which licenses are needed, how do you actually implement CALs in a Windows Server environment? Since standard CALs are not installed in the system, implementation focuses on administrative tracking and, for Remote Desktop, configuring a license server. We'll divide this section into two parts: first, actions for managing standard Windows Server CALs; second, how to implement Remote Desktop Services (RDS) CALs.

Managing Standard CALs in Windows Server

For standard Windows Server CALs (not related to Remote Desktop), consider the following:

  • They are not installed on the server: There is no setup wizard or product key for standard CALs; Windows Server does not automatically track these licenses. Compliance is based on the organization's honesty and responsibility.
  • Maintain manual tracking: Keep a record of how many CALs you own and how many users or devices are accessing the server. You can use spreadsheets, inventories, or license management software to ensure usage stays within licensed limits.
  • Configure licensing mode (informational only): Optionally, you can set in the server configuration or Group Policy whether you're licensing "Per User" or "Per Device." This does not enforce limits, but serves as an internal reference of your chosen model.
  • Perform internal audits: Regularly review and confirm compliance. If your company grows and new users or devices are added, acquire the additional CALs needed before exceeding license limits. This proactive habit helps avoid issues during external audits and last-minute purchases under pressure.

Implementing Remote Desktop Services (RDS) CALs

If your organization uses Remote Desktop in Windows Server, you must install and activate RDS CALs on a dedicated license server. The process is summarized as follows:

  1. Install the Remote Desktop Licensing role: On the designated server, open Server Manager and add the Remote Desktop Services role > Licensing Server. This enables the RDS licensing console on that machine.
  2. Activate the RDS license server: Launch the Remote Desktop Licensing Manager console (via Administrative Tools). Right-click the server name and select Activate Server. Follow the wizard, entering the requested company information to register your license server with Microsoft.
  3. Install the purchased RDS CALs: After activation, right-click the server again and choose Install Licenses. A wizard will open where you select the licensing program and enter the codes or keys provided by Microsoft for your RDS CALs. Complete the wizard and verify the new licenses appear in the console.
  4. Configure RDS Session Hosts: On each Session Host server, configure the licensing mode and specify the license server. For example, in the Session Host properties (or via Group Policy), set the licensing mode to Per User (or Per Device, depending on your CAL type) and enter the name of the license server you just activated.
  5. Verify functionality: Ensure users can log in via Remote Desktop successfully. In the RDS licensing console, you’ll see a log of issued licenses. Keep in mind that after a 120-day grace period, an unlicensed RDS server will begin denying new Remote Desktop connections.

Visual tip: A screenshot of the Remote Desktop Licensing Manager console showing installed CALs and the “Server Activated” status would be helpful to familiarize the reader with this interface.

Windows Server CAL licensesWindows Server CAL licenses

Practical Example: Combined Use of User and Device CALs

A company with 60 employees implemented Windows Server 2019 for domain and file services. Some staff members have dedicated PCs, but many floor operators share devices. The IT administrator chose a mixed strategy: they purchased 25 User CALs for employees with personal devices and 20 Device CALs to cover 20 shared PCs used in shifts. In total, they used 45 licenses instead of 60, achieving significant cost savings while still legally covering all users and devices.

License Management in Adobe Creative Cloud: Lessons for IT Administrators

The Adobe Creative Cloud platform is a modern example of user-based cloud licensing. Through the Adobe Admin Console, IT administrators can perform tasks such as:

  • Adding or removing users: Register new employees (typically with their corporate email) or remove users who no longer need access.
  • Assigning product licenses: Grant each user the Adobe Creative Cloud licenses they require (either the full subscription or individual apps like Photoshop, Illustrator, etc.).
  • Reassigning licenses easily: When an employee leaves or changes roles, their license can be released and reassigned in just a few clicks, ensuring no licenses go unused.
  • Monitoring usage and availability: The console shows how many total licenses were purchased, how many are assigned, and how many remain available—making it easy to track compliance and anticipate the need for more licenses or to redistribute existing ones.

In Adobe license management, there is no need to deal with physical devices; everything revolves around named users with cloud-based permissions. This approach parallels User CALs in Windows Server: each authorized individual has a license assigned to access services. The key difference is that Adobe automatically applies and validates these assignments through its servers, while Windows Server relies more on manual tracking and internal policy enforcement.

For an IT manager, administering the Adobe Admin Console becomes similar to managing accounts in Active Directory: you must keep user access up to date, revoke licenses when employees leave, and plan ahead for new hires or projects. In both environments—on-premises and cloud—the essential task is to proactively manage users and licenses to maximize efficiency and ensure compliance.

Conclusion

Proper implementation of Windows Server CAL licenses is not just an administrative formality—it’s a critical step to ensure legal compliance and IT stability within a company. By understanding the types of CALs and planning their use according to specific needs (whether through User CALs, Device CALs, or a combination), an IT administrator can optimize costs and avoid unpleasant surprises during software audits. Proper CAL management enables a company to grow in an organized way, adding users or devices without falling out of compliance.

In today’s world—where local infrastructure and cloud services coexist—the IT administrator’s role extends to mastering various licensing platforms. Whether implementing CALs in Windows Server or managing users in platforms like Adobe Creative Cloud, the goal remains the same: providing each employee with the tools they need while maintaining license control. Effective license management not only avoids penalties but also boosts productivity by ensuring authorized users always have timely access and that software investments are fully utilized.

Frequently Asked Questions (FAQ)

What is a Windows Server CAL license?

A CAL (Client Access License) is a license purchased for each user or device that will access a Windows Server. It is not software that gets installed, but rather a legal permission: if 10 users are going to use a Windows Server, the company needs 10 CALs to be properly licensed.

What is the difference between a User CAL and a Device CAL?

A User CAL is assigned to one person and includes all the devices that person uses to connect to the server. In contrast, a Device CAL is assigned to a machine and covers any number of users who use that device to access the server. In short: a User CAL covers one user (with all their devices); a Device CAL covers one device (shared by multiple users).

How do I know how many CALs my company needs?

Count how many users or devices will access the server in total. If you're using User CALs, you'll need one license for each unique user (regardless of how many devices they use). If you're using Device CALs, count each distinct device that will connect (PCs, laptops, tablets, etc.). It’s advisable to purchase a few extra licenses in case more users or devices are added in the future.

What is the Adobe Creative Cloud Admin Console?

The Adobe Admin Console is the web-based platform where companies manage their Adobe Creative Cloud licenses. It allows administrators to add or remove users and assign (or revoke) Adobe product licenses centrally. This way, the administrator controls which users have access to Adobe software in the organization—similar to how User CALs in Windows Server control who has access to the server.