Client Licensing

In addition to server licenses (or per-processor licenses in the case of Datacenter), most editions of Windows Server require clients to be licensed with CALs or External Connectors. Two Windows Server features, Remote Desktop Services and Active Directory Rights Management Services, also require their own client licenses. (For prices, see the chart “Client License Prices for Windows Server“.)

Client Access Licenses

A Windows Server CAL gives one person or physical device the right to connect to and use any instance of the Windows Server (Standard, Enterprise, Datacenter, or Itanium editions) running within the organization. CALs are the only option available for licensing an organization’s employees and onsite contract employees. However, organizations can also use CALs to license nonemployees—such as business partners, suppliers, customers, retirees, and alumni users.

Organizations making even limited use of Windows Server internally are generally obligated to have each internal client licensed with a CAL for the most recent version of Windows Server deployed within their organization. For example, setting up a single Windows Server 2008 machine as a Dynamic Host Configuration Protocol (DHCP) server triggers the requirement that all clients that might possibly access it (even across a global network) be licensed with a Windows Server 2008 CAL, even though DHCP is arguably an ancillary service and is likely to be accessed infrequently.