Client Access License (CAL)

CAL, or Client Access Licence, is a license that grants a client machine access to a Microsoft BackOffice product running on a network of computers.

Waht is CAL (Client Access Licence)?

A license that grants a client machine access to a Microsoft BackOffice product running on a network of computers. Every client computer on a network, regardless of whether it is running a Microsoft or non-Microsoft operating system, requires a client access license (CAL) if it will be accessing any of the following Microsoft Windows NT or Windows 2000 services:

  • File services, for accessing shared files and folders on a server
  • Print services, for accessing shared network printers
  • Remote Access Service (RAS) or Routing and Remote Access Service (RRAS)
  • File and Print Services for NetWare (FPNW)
  • File and Print Services for Macintosh (FSM)
  • Microsoft Transaction Server (MTS) and Microsoft Message Queue (MSMQ) Server access
  • Windows NT Terminal Server functionality

Client access licenses can operate in one of two modes:

  • Per Server licensing, which is based on concurrency of access to network resources
  • Per Seat licensing, which is the more commonly implemented solution and is supported by all BackOffice applications