Microsoft States in MSKB281258

Licenses Required When Using Terminal Services Client Software
This article applies to…
This article was previously published under MSKB281258
SUMMARY
The following licenses are required when you deploy a Windows 2000-based server running Terminal Services in Application Server mode on your network:
Windows 2000 Server License: This license is included with the purchase of the product.
Windows 2000 Server Client Access License: This is required for each computer or Windows-based terminal that connects to the Windows 2000-based server. Client Access Licenses permit clients to use the file, print, and other network services provided by Windows 2000 Server. The Terminal Services component of Windows 2000 Server requires Per Seat licensing for the Windows 2000 Server Client Access License, except when you purchase the Windows 2000 Terminal Services Internet Connector license.
Additionally, one of the following two licenses is also required:
Windows 2000 Terminal Services Client Access License: This license provides each client computer or Windows-based terminal the legal right to access Terminal Services on a Windows 2000-based server. For example, you must have this license to start a terminal session and run Windows-based programs on the server. All non-Windows 2000-based clients must have this type of license.
Windows 2000 Professional or Microsoft Windows XP Professional License: This license permits the installation of Windows 2000 Professional or Windows XP Professional, in addition to providing the legal right to access Terminal Services on a Windows 2000-based server. A computer that is running a licensed copy of Windows 2000 Professional or Windows XP Professional does not require a Terminal Services Client Access License.

Note that Microsoft Windows XP Home Edition and Microsoft Windows XP Embedded both require the purchase of a Terminal Services Client Access License to access Terminal Services on a Windows 2000-based server.
MORE INFORMATION
For additional information, click the article number below to view the article in the Microsoft Knowledge Base:
237801 Windows 2000 Terminal Services Requires Licensing Service

NOTE: A Windows 2000 Terminal Services Licensing server is still required when you access a Windows 2000 Terminal server and you use Microsoft operating systems that can use a built-in token. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
291807 Terminal Services Licensing Server Required for Windows Server Terminal Services Clients

CLIENT TYPE PROTOCOL WINDOWS 2000 CAL TERMINAL SERVICES CAL METAFRAME
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DOS ICA X X X
WIN 3.11 ICA X X X
WIN 3.11 RDP X X
WIN 98/95 ICA X X X
WIN 98/95 RDP X X
WINDOWS NT ICA X X X
WINDOWS NT RDP X X
WIN 2000 ICA X BUILT IN X
WIN 2000 RDP X BUILT IN