Terminal Services enables all client application execution, data processing, and data storage
to be performed over any TCP/IP connection to a Terminal Server.
Terminal Services provides remote access to a server desktop through terminal emulation software.
This means that users can disconnect from a session without logging off. So they can
leave a session active (running) while disconnected and then reconnect to the existing session at another time or even from another machine.
The Terminal Services client software is a “super-thin client”.
it sends keystrokes and mouse movements to the Terminal server,
which manipulates the data locally and passes back the display.
This brings Windows desktops to machines that cannot run Windows, such as
legacy desktops including Win16, Macintosh, and Unix.
Terminal Services contains its own methods for licensing clients that log on to Terminal servers.
This enables users to simultaneously log on to multiple Terminal Server sessions from different desktops.
The Terminal Services licensing method is separate from the method used for Windows 2000 Server clients.
With Windows NT4, Terminal Services Edition was a separate product called Terminal Server Edition.
With Windows 2000, Terminal Services is a built-in feature of Windows 2000 Server.
Terminal Services Licensing includes four primary components:
- the Microsoft Clearinghouse,
- a license server,
- a Terminal server, and
- client licenses.
Terminal Services is enabled in either Remote Administration mode
or Application Server mode.
Remote Administration allows you to administer a Windows 2000 Server computer remotely over any TCP/IP connection.
You can administer file and print sharing, edit the registry, or perform any task as if you were sitting at the console.
Remote Administration installs only the remote access components of Terminal Services.
It does not install application sharing components, which means you can use Remote Administration with little overhead.
Terminal Services allows up to two concurrent Remote Administration connections.
No additional licensing is required, and you do not need a license server. In Application Server mode, you can deploy and manage applications from a central location. You can install applications directly on the Terminal server, or you can use remote administration. After an application is deployed in Terminal Services, clients can connect through a remote access connection, a LAN or WAN, and from many types of clients. Client licensing is required when deploying a Terminal server as an application server. Each client computer must have the Terminal Services Client Access License as well as the Windows 2000 Server Client Access License .
The three standard permission levels for Access Control Settings:
- Full Control
- User Access
- Guest Access
There are no group policies to control Terminal Services connections.
Microsoft provides for free the
Terminal Services Remote Desktop Connection
for Windows XP SP1, Windows 2000, and even prior systems.
Download it
Microsoft White Paper: Using Terminal Services for Remote Administration of the Windows 2000 Server Family
Windows Remote Access and Terminal Services
"Access Denied" by
Application Development
netsh diag gui 
