I found this discussion thread interesting as it seems like there now is a version of adskflex.exe available for Linux but it requires you have Maya 2010. It would be good if Autodesk made this available directly from their website as well.
Even though JTB FlexReport still needs Windows to be installed on it can report FLEXnet/FLEXlm usage from other operating systems like Linux, Solaris Sparc, etc.
Update: Download available from DL16273721
Autodesk IPv4 Network License Manager for Linux 32-bit and Linux 64-bit
The Autodesk Network License Manager for IPv4 networks using Linux® 32-bit or 64-bit Red Hat® Enterprise Linux 5.0 WS (U4). Please refer to the appropriate readme file for installation instructions.