As part of the series on getting the best out of Windows Server 2003, here we look at Terminal Server. That's the bundled multi-user software which enables a Windows server to host multiple user sessions, typically using low-cost, thin client devices to handle the graphical user interface (GUI). Additional licences are required if you want to host remote applications, but for server administration the software can be used for free.

Going remote
Because it's free, it's worth trying out Terminal Server in remote administration mode. Imagine, no more trips to the machine room to add or change users, check on backups and so on - all these tasks can all be performed from your own desk.

Unfortunately, as part of its drive to make Windows Server 2003 as secure as possible, the Terminal Server software isn't included in the default server setup. Rather you have to log on as an administrator and choose Add/remove Programs in the Control Panel, to start a wizard to guide you through setup.

Up to two simultaneous remote sessions can be supported in remote administration mode, accessed using either a custom thin client device or software based client. The software approach is the easiest to start with and, if you use Microsoft's Remote Desktop Connection, the cheapest too.

On a Windows XP system start Remote Desktop Connection from the Start/All Programs/Accessories/Communications menu. Otherwise download it here for use on other versions of Windows. An ActiveX implementation can also be downloaded and used in a browser.

From the client
To start a session simply point the client at the DNS name or IP address of the host server. You're then presented with an XP-like desktop on the local machine, from which you logon in the usual way.

Although it appears to be running locally, the desktop and any applications started from it are all hosted remotely on the server. This obtains keyboard and mouse input and refreshes the local display using a protocol called RDP (Remote Desktop Protocol) which is much enhanced in Windows Server 2003. Earlier versions were limited to 256 colour displays, but the latest version can handle up to 24-bit colour and resolutions up to 1600 x 1200. The client hardware also plays a part here, however, so you can't select a higher resolution or more colours than the local graphics controller can handle.

Another big change in RDP 5.1 is the ability to make local client resources available to a server session. So, for example, a remote application can open files on local storage devices (including external USB devices), use the local audio facilities to plays sounds and print to local printers.

In fact just about anything you can do from the server console can be done remotely although there are exceptions. In particular some programs (typically backup and mail server applications) require a "real" console session to operate. The only option then is either a hardware KVM (Keyboard Video Mouse) switch or remote control software to mirror the console session itself rather than run a separate session completely.

Application server mode
Apart from the two-session limit, there's no difference in functionality between Terminal Server in remote administration mode and when configured as an application server. To try it in this mode the software can be installed and used for 90 days free of charge. After that, however, it reverts to supporting two remote administration sessions unless you buy and install the appropriate licences.

You don't actually need a licence for the server-side software, but you will have to buy a Client Access Licence (CAL) for every user - just as when accessing a server from an ordinary networked PC. In addition, every session hosted by the Terminal Server requires a separate TS-CAL which can be purchased on a per user as well as a per device basis.

Performance is likely to be an issue in application server mode, much more than when using Terminal Server for remote administration. Because it has to host multiple desktops and applications the specification of the server is very important. On the plus side the Windows Server 2003 implementation is the most scalable yet and can take full advantage of extra processors and memory. Server and session based load balancing facilities have also been added with improvements too in manageability via a new WMI (Windows Management Instrumentation) provider and support for Terminal Server in Group Policy.

Finally, Terminal Server can be enhanced with add-ons from Citrix and other specialists, plus there are lots of custom thin clients available, including tablets and portable wireless products. The end result may not be quite the same as running Windows locally, but it's a good alternative, especially for task-oriented users. Moreover, because everything is hosted centrally, it's a lot more secure and an easier to manage solution as well.