This article shows a workaround whenever you cannot connect to a Windows Terminal Server anymore with either rdesktop or KRDC (which uses rdesktop). KRDC is an RDP client, part of the KDE distribution. Running rdesktop directly from the command line results in the following error:

I don't know exactly why this happens, but what I've learned is that a temporary license is created which is valid for a certain amount of time. Then the license expires and you cannot use it anymore. By supplying a different name, a new temporary license is created. It might not be completely correct, but on the other hand, I don't care enough to figure this out. I was more interested in a fix, which is -fortunately- easy. Just add the -n parameter to the rdesktop call, followed by some arbitrary name:

Whenever this name stops working, just make up a new one and reconnect. By default, rdesktop sends your hostname to the server, the -n flag is used to override it. This is also the reason why some people report that things work again when they change their machine hostname. But I like this solution better.

Within KRDC, you can also send additional parameters to rdesktop. Go to Settings, Configure KRDC..., Plugins, click the wrench at RDP and enter -n aoueidhtns in the Extra Options field. It's also possible to specify this for a single host.

When solely using the rdesktop command, you could also alias it to the following:

which generates a new name every day.