Article ID: 886209 - View products that this article applies to.
When users try to connect to a remote desktop on a Microsoft Windows Small Business Server 2003-based network by using a Remote Web Workplace connection, they receive the following error message:
This issue occurs when users click Connect to Server Desktops or Connect to Client Desktops on the Remote Web Workplace site and then try to connect to one of the server desktops or client desktops in the list.
Connectivity to the remote computer could not be established. Ensure that the remote computer is on and connected to the Windows Small Business Server network.
This issue may occur if a process that is running on the Windows Small Business Server-based computer is listening on Transmission Control Protocol (TCP) port 4125. On a Windows Small Business Server-based computer, the Remote Web Workplace uses TCP port 4125 for its remote desktop feature. Sometimes, another process may use TCP port 4125 before Remote Web Workplace can claim port 4125. If another process is listening on this port, Windows Small Business Server cannot respond to the remote computer's connection request.
The most common process that claims TCP port 4125 is Mad.exe. Mad.exe is the Microsoft Exchange System Attendant service.
To resolve this issue, determine which process is listening on port 4125, and then stop that process from listening on that port. To do this, follow these steps:
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
(https://support.microsoft.com/kb/322756/ )How to back up and restore the registry in Windows
This issue may also occur if you have a router or a firewall that is configured between the Windows Small Business Server computer and a client computer. In this scenario, verify that the router or the firewall is configured to permit traffic on TCP port 4125 to the Windows Small Business Server computer. For additional information about how to configure or troubleshoot network connectivity issues, click the following article numbers to view the articles in the Microsoft Knowledge Base:
(https://support.microsoft.com/kb/306802/ )How to configure Small Business Server for full time Internet access with two network adapters
(https://support.microsoft.com/kb/309633/ )How to configure an SBS for full time Internet access with a single network adapter
(https://support.microsoft.com/kb/329155/ )You receive a "The server may be too busy" error message when you try to connect to Terminal Services on a Small Business Server 2000 computer
(https://support.microsoft.com/kb/154596/ )How to configure RPC dynamic port allocation to work with firewalls
Article ID: 886209 - Last Review: December 3, 2007 - Revision: 4.3