Cascading and Distributed License Servers for Autodesk Products

By Anna Liza Montenegro | IT

As you may know, LMTOOLS instances on a server are not aware of, and do not communicate with, other servers running LMTOOLS. In a distributed license server environment, the client computer will query servers in the order specified in the ADSKFLEX_LICENSE_FILE environment variable, in the registry entries and the LICENSE.LIC file (in that order).

Therefore, we might assume when a client requests a license, it will query the first server in its list and look for an available license. If it doesn’t find one there, it checks the second server for an available license, and so forth.

It turns out that this is not the case. Instead, the cascading sequence has priority, regardless of which server the client computer is told to look for first.

  • For example, consider the following cascade sequence:

AutoCAD Structural Detailing 2015
Building Design Suite Standard 2015
AutoCAD Revit Structure Suite 2015
Building Design Suite Premium 2015
Plant Design Suite Premium 2015
Building Design Suite Ultimate 2015
Plant Design Suite Ultimate 2015
Education Master Suite 2015

  • Now, let’s set up two license servers:

LICENSE_SERVER_01 has 10 licenses of Building Design Suite Premium
LICENSE_SERVER_02 has 5 licenses of AutoCAD Revit Structure Suite

  • The client computer’s environment variable is configured as follows:


When the client computer opens up AutoCAD, it will actually pull its license from LICENSE_SERVER_02. Even though LICENSE_SERVER_02  is listed second in the ADSKFLEX_LICENSE_FILE variable, the ARSS is earlier in the cascade sequence, and the client will check out that license first.

The cascading sequence is hard-coded, so there are only a few ways to work around this sequencing. The most direct is to use an OPTIONS file on one or more of the license servers, to prioritize or exclude certain users obtaining licenses.

You can also put users into OU’s, and use group policy to prevent selected users from accessing specific license servers. Keep in mind that since this is a client-side solution, in some environments you may need to clean up the registry and/or CASCADEINFO.CAS file in order for this to work properly.

If you still need help with this issue, send an email to or call us at 888-768-7568.


Published on June 2, 2014 in IT.

About the Author

Anna Liza Montenegro develops design technology conferences for architecture, engineering, and construction (AEC) professionals as a forum to exchange innovative strategies, and best practices, and facilitate discussions into the technology trends driving significant change in building design and construction. As Director of Marketing and as a trained architect, these events are offered to AEC professionals by Microsol Resources, a value-added reseller of Autodesk, Bluebeam, Rhino, Chaos V-Ray & Enscape, Egnyte and other various technology partnerships.