Windows Server (2008 R2) blog by Kurt Roggen [BE]

Terminal Services Web Access (TS Web Access) is a TS role service in the Windows Server 2008 operating system that enables users to access RemoteApp programs or the full terminal server desktop from a Web site.
By default, the TS Web Access Web site enables you to point to a single terminal server or to a single terminal server farm to populate the list of RemoteApp programs that appear on the site. If you have multiple terminal servers or multiple terminal server farms, you could even use Windows SharePoint Services to create a single Web access point for RemoteApp programs and/or full terminal server desktop connections that are available on different terminal servers.

After you install TS Web Access, you can specify (on the Configuration tab) from which terminal server you want to populate the Web Part. Any RemoteApp programs on the specified terminal server that are configured to show in TS Web Access will appear in the Web Part. Because the Web server can populate the list from an external data source, the TS Web Access server does not have to be a terminal server, but could be running on a dedicated (virtualized) webserver.

Remote Desktop Web Connection

Terminal Services Remote Desktop Web Connection enables a user to connect to the desktop of a remote computer from the TS Web Access Web site. To connect to a remote computer, you must meet the following conditions:

• The remote computer must be configured to accept Remote Desktop connections.
• The user must be a member of the Remote Desktop Users group on the remote computer.

A user can access Remote Desktop Web Connection by clicking the Remote Desktop tab on the TS Web Access page (see below). As an administrator, you can even configure whether the Remote Desktop tab is available to users. Additionally, you can configure settings such as the TS Gateway server to use, default device and resource redirection options.

All these settings will be set from the ASP.NET Application Settings (see below) on the TS Virtual Directory in IIS.
To configure the default TS Gateway server, double-click DefaultTSGateway, enter the fully qualified domain name of the TS Gateway server (eg: tsg.company.com).

To configure the TS Gateway authentication method, use GatewayCredentialsSource and enter the number that corresponds to the desired authentication method in the Value box.

These settings correspond with the authentication options on the RDP client.

To configure whether the Remote Desktop tab even appears on the TS Web Access page, use ShowDesktops. In the Value box, type true to show the Remote Desktop tab or false to hide the Remote Desktop tab.

To configure default device and resource redirection settings, use the setting that you want to modify (xClipboard, xDriveRedirection, xPnPRedirection, xPortRedirection, or xPrinterRedirection). In the Value box, type true to enable the redirection setting by default or type false to disable the redirection setting by default.

NOTE: All settings above only apply to the Terminal Services Remote Desktop Web Connection.

All default values are listed below.

The changes made above are located in the %windir%\Web\TS\Web.config file and take effect immediately on the TS Web Access Web site when the webpage is refreshed.

NOTE: Terminal Services Web Access (TS Web Access) requires the most recent update to the Remote Desktop Connection (RDC) client software. 
You must have Remote Desktop Connection (RDC) client version 6.1 installed to use TS Web Access. RDC 6.1 is available with the following operating systems:

• Windows Server 2008
• Windows Vista with Service Pack 1 (SP1)
• Windows XP with Service Pack 3 (SP3)

For more information: RDC client requirements for Terminal Services Web Access in Windows Server 2008

Related reading:

• Step-By-Step Guide: Windows Server 2008 TS Gateway Server Step-By-Step Setup Guide
• Step-By-Step Guide: Customizing TS Web Access by Using Windows SharePoint Services
• Servicing Branch Offices with Terminal Services
• TechNet Webcast: Windows Server 2008 Terminal Services RemoteApp and Web Access (Level 300)