Terminal Services Client Cannot Connect to NLB Cluster TCP/IP Address (280805)

SYMPTOMS

If Network Load Balancing (NLB) is installed on a Windows 2000-basedserver or Windows Server 2003-based-server that is running Terminal Services, a client that attempts to connect to the cluster TCP/IP address may be rejected with the following message:

The client could not connect to the Terminal server. The server may be too busy. Please try connecting later.

Connecting to the host address of the Terminal Services server works correctly.

CAUSE

Remote Desktop Protocol (RDP) is currently able to "listen" only on either one IP address or all addresses. RDP cannot listen on a selection of addresses.

Using the netstat -an command shows that when RDP is enabled on all adapters, port 3389 is listening on TCP/IP address 0.0.0.0. However, when RDP is enabled on only one adapter, only the first TCP/IP address is shown as listening on port 3389.

NOTE: "Nbtstat" is used to display local or remote NetBIOS information. "Netstat" is used to show TCP connection specific information including "listening" ports.

RESOLUTION

To resolve this issue, use either of the following methods:

Method 1

Click Start, point to Run, type tscc.msc in the Open box, and then click OK.
Double-click RDP-Tcp in the right pane.
On the Network Adapter tab, click All network adapters configured with this protocol in the Network adapter box.

Method 2

Make sure that the cluster IP address is listed as the primary IP address for the network adapter. (This prevents access to the Terminal Services server by using the host address, but enables the NLB functionality to work.)

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.