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Client access license

(also CAL)

Client access license definition

A client access license is a software license that permits a client to access server software services.

See also: access control entry, access control system, discretionary access control, network access control, mandatory access control, risk-based access control, access management

Types of client access license

  • User CALs. A user can access the server from any number of devices. This option is ideal when users access the server from multiple devices, such as a work computer, personal laptop, smartphone, or tablet.
  • Device CALs. Many users can access the server from the same licensed device. This option is suitable in scenarios where multiple users share the same device, like a computer in a training room or a workstation in a factory.

Organizations often use a combination of both types to optimize their workflow based on their particular mix of users and devices.

Usage of CALs

Businesses that use server-based software applications are the most common users of CALs. For example:

  • Windows Server environments
  • Database servers like Microsoft SQL Server
  • Email and communications servers like Microsoft Exchange or SharePoint
  • Remote Desktop Services (RDS)
  • Enterprise resource planning (ERP) or Customer relationship management (CRM) systems like Microsoft Dynamics
  • File and print services