Running Linux, 5th Edition - Matthias Kalle Dalheimer [496]
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To interoperate with Microsoft's RDP, rdesktop uses industry-standard protocols: the Internet Engineering Task Force standards discussed in RFCs 905 and 2126. Those documents implement the Telecommunication Standardization Sector ITU-T.128 application sharing protocol. Matthew released rdesktop under the GNU Public License (GPL) as free, open source software.
TSClient is the most popular and easy-to-use graphical interface to rdesktop. Most Linux distributions provide rdesktop and TSClient in their default configurations. Occasionally, you might have to specify the RDP components as options when installing Linux or download them from a repository.
Setting up Windows Terminal Services
Unless you have configured a Windows server, you may find it difficult to visualize the kinds of tasks required to enable Linux to use Win32 applications from NT Version 4 or 5. Initially, you will need a Microsoft NOS and the ability to install Terminal Services. You will also need to configure a way for the terminal server to resolve your Linux workstations to a TCP/IP address.
Figure 28-2 provides a look at how a Windows 2000 server sets up Terminal Services. Notice the large screen with the heading Windows 2000 Configure Your Server. On the left side of that window under the heading Application Server, you can see the subheading Terminal Services.
Figure 28-2. Configuring Terminal Services in Windows 2000 and Windows Server 2003
The small window in the foreground of Figure 28-2 shows the progress of installation while the operating system installs the terminal server components in the background. Prior to the release of Windows 2000 Server, you had to order a separate component to run applications from NT. Now, Terminal Services come as an integral part of the NOS.
Figure 28-3 shows the same process for Windows Server 2003. The configuration wizard still displays a dialog screen, but you see a more verbose set of instructions on the wizard screen.
Figure 28-3. The configuration wizard in Windows Server 2003
One of the major differences in the 2003 version of the NOS deals with license management. Microsoft requires activation of Client Access Licenses for its latest server. So, in addition to installing Terminal Services, users must install a license server and activate it over the Internet or by phone.
If you have fewer than 25 users requiring Terminal Services, license services can reside on the same computer. If you have more than 100 users accessing the terminal server, you will want a second computer just to manage the Client Access Licenses.
Figure 28-4 shows how to configure a Windows 2003 server in the role of a terminal server. Select the role and double-click it. You can see, in the highlighted section of this screen, a "Yes" under the column entitled "configured."
Figure 28-4. Service Options in Windows Server 2003
To summarize what we just covered, remember the following:
You must set up Terminal Services on Microsoft servers explicitly by adding it as a Windows component.
Terminal Services require Client Access Licenses, and the current Microsoft servers require you to activate the licenses with Microsoft or the server will refuse connection requests.
Microsoft applications running in terminal service mode require licenses for each user and require explicit activation.
Connecting to the terminal server
Before you can run a Windows application on your Linux desktop from the terminal server, you need to install and set up rdesktop. The best way to run rdesktop involves using TSClient. TSClient is simply a graphical interface to rdesktop. You can execute the rdesktop commands from a console, but the TSClient GUI makes connecting easier for some people. It also allows you to save a configuration file for one or more terminal servers to which you might connect. Figure 28-5 shows TSClient running Microsoft