If you want to reserve (block) a specific license of a CAD application from your Autodesk license server FlexLM/FlexNet for a particular user or a user group, use the option "RESERVE".
In the license folder on your license server, create or edit the text file ADSKFLEX.OPT. Using Notepad.exe, add the reservation lines into this file - e.g.:
RESERVE 1 86295ACD_2015_0F HOST HP_Workstation_D18
RESERVE 1 86314INVNTOR_2015_0F INTERNET 192.168.0.117
Or you can limit access to licenses from specific machines - e.g.:
EXCLUDE 86296PLNT3D_2015_0F INTERNET 192.168.0.*
MAX 3 86268PDSU_2015_0F INTERNET 192.168.0.*
EXCLUDE_BORROW 86268PDSU_2015_0F INTERNET 192.168.0.*
In the above examples, 1 license of AutoCAD 2015 is reserved for the computer with network name "HP_Workstation_D18", and 1 license of Inventor 2015 is reserved for the machine with IP address "192.168.0.1". Using any licenses of Plant 3D 2015 is excluded from workstations with IP addresses starting with "192.168.0." and using licenses of Product Design Suite Ultimate 2015 from these machines is limited to maximum 3 (concurrently), and at the same time these licenses can't be borrowed from these machines. You need to restart the license service after you edit the OPT file.
NLM Feature codes of the individual CAD products can be found on the page Products and on knowledge.autodesk.com.