I had to change the RWW port number recently, due to recent Windows updates on the server hosting RWW that blocked the original RWW port.
By default, RWW receives requests through port 4125 and then forwards the request to the Remote Desktop app at port 3389. There are several potential fixes you can find around on the Internet, but none of those seem to work – or they only work in specific instances. The problem with this issue is that port 4125 is not exposed until RWW activates. Also, if another process is using port 4125, such as a system attendant type of service, you won’t see the port in use until that process is active. But, what is true is that a recent Microsoft update (not sure which one at this point) either blocked 4125 or added a process that utilizes or locks it. Changing the port number for RWW from 4125 to 4150 was the only solution.
Changing the RWW port is done through a registry change. Once the registry is changed, the change to RWW is automatic, i.e., you don’t have to restart IIS or anything. On a more critical note, don’t forget to change the router or gateway port forwarding from 4125 to 4150 so that RWW can be accessed externally.
To change the RWW listening port:
- In the registry, navigate to: HKLM/Software/Microsoft/Small Business Server/RemoteUserPort
- Change the port value from 4125 to 4150
