This hack will allow you to connect multiple time to your Microsoft Windows XP machine using an RDP client coming from a Mac, Linux, or another PC like a real Terminal Server, or a Windows Server running Citrix.

In detail, this hack patches many pieces of Windows XP in order to allow the same Terminal Services functionality that you find in Microsoft Windows Terminal Server, but without the licensing costs. The stability of the hack has not been verified, but the virtual machine used has been running for over a week now with 20 conenctions to it and has yet to fail once.

In order to perform the hack you will need one external file, some guts, and a backup. The backup is extremely important. I highly recommend that you test the procedure using virtualisation technoloy like Parallels, Virtual Server (free), or VMWare Server (also free). You have no excuse to procede without a backup – consider yourselves warned.

Let’s begin.

The file needed for the hack is actually a combination of some registry tweaks and DLL/EXE patches made by “antiwpa”. antiwpa is known for dealing with another Windows XP issue that we won’t get into here – I’m sure you can guess what it is easily.

No that you have the file, and backup, we’ll extract it and start the install process. It’s quite simple – you double-click on the application, it starts a command line window, you press a key and the patch commences. Eventually the command line portion will end and you will get a Windows warning regarding system files having been replaced – we’ll cancel the restore “feature”, and let Microsoft know that we are running untested code by pressing the “yes” button on the next window.

A second patcher launches with full GUI this time. We click on the “patch” button and we are finished. Easy huh?

Moving on… If you try to connect to the XP machine now, you will notice that the maximum number of connections has been reached. This is easy enough to fix, but it’s readily apparent where we need to go. Click on Start, then Run, and type in:

gpedit.msc

Once the Group Policy Editor has opened, navigate to “Computer Configuration”, “Administrative Templates”, then “Terminal Services”.

In the “Terminal Services” tree, you’ll see a policy named “Limit number of connections”. Double-click on this policy. Set the policy to enabled, and adjust the maximum connections to suit your need. I recommend trying “2″ to start off with.

Now reboot your machine, and attempt to connect the amount of times you have specified. If you need mre connections, navigate back to the policy editor and set the maximum amount higher.

Once you have completed your testing, back the machine up once more for good measure. If you don’t have disk imaging software, I’d recommend using the open source g4u – otherwise commercial applications such as Symantec Ghost will work.

Moving on, if you feel the need to manage the users (log them off, control sessions) like on a real Terminal Server, you can grab a copy of the “tsadmin.exe” file from a Windows Server 2003 machine’s “SYSTEM32″ folder and copy to the Windows XP machine’s SYSTEM32 folder. Running TSAdmin is as easy as clicking on Start, Run, then typing tsadmin, but you might also want to make a shortcut to the file for good measure.