Last week I had a very peculiar problem with the Terminal Server licensing.
I couldn’t connect to the licensing server anymore, even though it was running. The Terminal Server Licensing app couldn’t detect it anymore. The only thing that still worked was a network ping, but as far as Windows was concerned, we were running unlicensed.
The weird thing was that Terminal Server itself disagreed, and kept working without complaints. One of these servers had been running for a year already, so it was not the 120 day grace period that was hiding an underlying problem.
At the time I didn’t really understand why it still worked, but my colleague pointed out the the system time was wrong. The licensing server is a virtual machine, and for some reason, the time of the virtual machine was not linked to the NTP controlled time of the host. And as we all know, if the system times are off by n minutes, the mutual authentication fails and no secure connection can be established.
As it turns out, Terminal Server Licensing is ever more stupid than I already knew. Not only doesn’t it count licenses, but the Terminal Servers don’t even connect to the license server to ask for licensing. Because if they did, then they would have complained about it since connecting was no longer possible.