Hi,
We have many offices and university departments with exactly your requirement - different IP sub-ranges accessing a single network license server, including VPN ranges which can have completely different number values. The IP sub-range system seems to handle these pretty well so I am very interested in the problems you are having.
My guess is that the way forward is to review the ranges you are using and see if there isn't some sort of glitch in the way they are ordered or specified. Could you send them to support@ecotect.com and mark the message to my attention. If you can provide your POP number as well (or even an account email), I can compare it against what is stored at our end.
I'm confident that it will be something pretty simple and that we should have you up and running without these problems quite quickly...
Kind regards,
Andrew
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Dr. Andrew Marsh
Principal Software Engineer
AEC-Simulation
Autodesk, Inc.