Useful Tricks For Connecting Remote Desktop Protocol (RDP) Client To Localhost

Windows XP users must have noticed that while trying run the Remote Desktop (RD) Client to establish a RDC (Remote Desktop Connection ) with the localhost (i.e. on the own computer itself) via the Terminal Server service, the RDC session either cannot be established or gets disconnected giving an error message. (This post will help you fix the problem of Remote Computer Disconnected the session because of an error in the Licensing protocol in Windows Vista. )

The error message notifies you that the RDP client was unable to connect as the user is already connected to PC’s console and a new session can’t be established.

Basically, the behavior of the Remote Desktop service in Windows XP prevents a Remote Desktop Connection from being established with or locahost. Generally, users who wish to have two sessions on the console or want to tunnel RDC through encrypted Secure Shell (SSH) try to establish a RDC with the localhost.

Sometimes users also attempt to establish RDC with the localhost in order to check whether the termsrv.dll patch has worked to unlock the restriction on concurrent RDC sessions.

However, it is possible that you enable Remote Desktop so as to connect to the localhost for establishing another desktop session. Below mentioned are a few methods that you can apply.

Method 1: Connect RDC to IP address

The trick can be used with Media Center Edition and Professional (Pro) Edition of Windows XP released prior to XP SP2 (Service Pack 2). The IP address is an internal TCP/IP loopback IP address and RD service in Windows XP Media Center and Pro editions prior to SP2 support connection through this loopback address.

However, connection via localhost or string is actively blocked.

Method 2: Connect to Terminal Services using another Non Standard Port.

By this method you may establish a RDC with the localhost (or address) by using another non standard port rather than the default (i.e. 3389) one. This trick is useful in XP SP2 & SP3 versions which do not support localhost connection through loopback IP address. RD listens and connects using the port 3389 by default.

Hence, to use this method you need to first change the listening port.

Method 3: Run RDC (mstsc.exe) Simulated as being run from a different Operating System

In this trick you actually make Terminal Services to think that the RDP Client which is trying to establish a connection with the localhost is from a different operating system, ultimately indicating that the RDC is from a different remote computer. Follow the below mentioned steps:

  • Create a folder named “RDC” in C drive.
  • Navigate to the folder “C:\Windows\System32\ and copy the files “mstscax.dll” and “mstsc.exe” to the newly created folder (i.e. to C:\RDC).
  • Now go to “C:\RDC”, right click on the file “mstsc.exe” and select the option “Properties” from the right-click context menu.
  • Go to the tab “Compatibility”.
  • Check (Tick) the checkbox corresponding to the option for running the program in a compatibility mode for the chosen OS and select Windows Me/ Windows 98 OS from the dropdown list.
  • Then, click on the button “OK”.
  • Double-click on “mstsc.exe” in the “C:\RDC” folder so as to run RDC and now the RDP client will be able to connect to address or localhost.

You need to remember that, when you log on to the RD session, you need to log on as a different user. Otherwise, you might be forcibly logged out.