FYI – I found this helpful with one customer. Port 4125 usage battle between services. This is always a pain when a user calls reporting this error. To fix it I’ve been restarting the Microsoft Firewall service and/or the IIS Admin service; however, that didn’t address the root cause.
Users cannot connect to remote desktops by using the Windows Small Business Server 2003 Remote Web Workplace
December 3, 2007
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:
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 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.
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.