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Can you help me with my software licensing question?

We have a Xenapp 5.x server running for over a year now. It does not have any purchased Terminal Services (Remote Desktop) licenses installed. It is running on a Windows 2008 Server box. I am aware that Terminal Services runs fine for about 3 months and then supposedly stops issuing licenses. On occasion, Xenapp stops working and we see lots of License errors in the event log, although not necessarily every time. In most cases, a reboot or 2 resolves the problem. We figured it was because of the lack of TS licenses. I spoke with Citrix and they said we had to have the licenses, but it begs the question that if we have to have the licenses, how does it work the majority of the time without them!!?? I have not received a straight answer yet and before I tell my client to shell out more money, I need to understand the technical reasoning for how this is actually working if we are breaking the rules here. We will buy the licenses if necessary, but there has to be an explanation for this. I am hoping the community can help where Citrix apparently cannot. Thanks much!

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marked as duplicate by Iain Jan 27 '12 at 23:00

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Straight answer: you need a valid TS license for every Citrix connection.

The reason is that Citrix runs ON TOP of TS: each Citrix ICA session is actually a RDP session that uses a different connector.

It's a real pain because the two systems have different licensing models, but it's the way things are.

As to why it used to work, it's pretty simple: RDP clients, when they initially connect, are issued a temporary license that are converted to permanent license when they expires. The TS license server itself never stops running, even though you have not installed any license. However, to have the clients successfully connect once their temporary license have expired you need to either have the TS license server issue them a real license (which can only be reclaimed if the client doesn't connect for, IIRC, 3 month) or delete the temporary license on the client and have a new one re-issued.

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Technically the reason is that you are using a terminal session, regardless of how the data is transmitted. I.e. if you used VNC in each session you'd still need a licence for each session. –  Andrew J. Brehm Jul 2 '10 at 16:04

It doesn't matter if it works without them, you need TS CALs to be properly licensed.

The technical reason for it to be working shouldn't really matter, most software in this world will not block their use even when not properly licensed.

There's also a history of per-user TSCALs not being enforced, where you simply set licensing mode to per-user and it stops enforcing it (probably because it's a lot harder to track users than to track devices for the licensing service). Citrix however does track this but in a completely different manner (concurrent users) adding to the confusion. That still doesn't mean you can get away without purchasing an appropriate amount of user CALs ^^

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I think you misunderstand my motive. We are not trying to avoid buying licenses, as a matter of fact we did buy them. I actually prefer to understand how things work so that I can give my clients well founded answers and recommendations and explain event the the most non-intuitive behavior. –  John Virgolino Jul 26 '10 at 4:32
    
Well, most software continue to work when under-licensed, in my experience. Even if this case was a glitch or a fluke, in most cases there's simply nothing stopping it - ie the technical reason is just that. See the KB I added a link to. –  Oskar Duveborn Jul 26 '10 at 11:21

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