If you use rdesktop to gain access to a Windows Server 2008 Terminal Server from Linux, you may experience the following error:

rdesktop my.terminalserver.com

Autoselected keyboard map en-us

disconnect: Internal licensing error.

This happens when your terminal server is Windows Server 2008 or 2008 R2, the licensing mode is set to "per device", and you are using rdesktop 1.7.0 or less. There are two ways to resolve this error. You can either set the licensing mode to "per user", or you install rdesktop 1.7.1. rdesktop 1.7.1 includes a patch for the problem connecting to 2008 terminal servers with "per device" licensing.

To fix error on Ubuntu Linux, install rdesktop 1.7.1:

sudo apt-get install libx11-dev libssl-dev

wget http://iweb.dl.sourceforge.net/project/rdesktop/rdesktop/1.7.1/rdesktop-1.7.1.tar.gz
tar -zxvf rdesktop-1.7.1.tar.gz
cd rdesktop-1.7.1
./configure
make
sudo make install

​You may have to close and open a new terminal window before you run rdesktop again, but you won't receive the error any more.

***Note***

There are a couple of workarounds for this problem that have surfaced, but they are all outdated as of rdesktop 1.7.1. Do not use these workarounds, as 1.7.1 fixes the issue. Here are two of the work arounds:

1:

rm -rf ~/.rdesktop

touch ~/.rdesktop

rdesktop will complain that .rdesktop isn't a directory, but it will connect anyway.

2:

 chown -R root.root /home/<username-with-problems-here>/.rdesktop

chmod -R 444 /home/<username-with-problems-here>/.rdesktop

Then delete ~/.rdesktop/license.<hostname>