Restricting access to an Ansys license on a license server



Access to the license can be controlled by the ANSYS License Manager on your license server for OpticsBuilder or OpticStudio. These access rules can be defined in the 'ansyslmd.opt' options file.

Important note

This article only applies to those using Ansys FlexLM licenses. Those using legacy Sentinel LDK licenses (starting with license number L or T such as L100000) should see this article. Those with black USB network licenses (from 22000-40999) should see this article
Authored By Don Dickinson (credit to Lumerical for most examples)


  • Ansys License Manager and installed OpticStudio or OpticsBuilder license
  • Access to the license server directly or via remote access. 
  • Root or administrator privilege. 

Examples of access control

  • Reserve a set of licenses for a particular group of users or a single user.
    e.g. if one user always needs access to a seat, a license can be permanently reserved for this user.
  • Exclude certain machines or users from a license.

First - know your license features 

These rules are applied to Opticstudio or OpticsBuilder which are defined in Ansys license files as a "feature". The features that correspond to these product editions are listed below.

Note for OpticStudio licenses, that each edition includes the levels of the lower editions. For example, if you have Enterprise, you also have the Premium and Pro levels listed in the license file. So if you are defining an access rule be sure to make rules that includes all ZOS levels below the edition you purchased. 

zos_level1 = OpticStudio Professional
zos_level2 = OpticStudio Premium 
zos_level3 = OpticStudio Enterprise 

zob_level1 = OpticsBuilder Enterprise
zob_level2 = OpticsBuilder Enterprise

Location of the 'ansyslmd.opt' file

Note: Create the 'ansyslmd.opt' (text) file using notepad, if this file is not found in your installation folder. The default location is shown below).


"C:\Program Files\ANSYS Inc\Shared files\Licensing\license_files\"



Keywords to use


  • Defining a user that for use with an option. This option is case-sensitive.
     USER username
  •   Example: Reserve 1 seat of an Opticstudio Premium license to USER bill. Note that if you only have a 1 seat license, Bill will be the only user able to use the license. 
    RESERVE 1 zos_level1 USER bill
    RESERVE 1 zos_level2 USER bill


  • Define a group of users for use with any options. This option is case-sensitive.
    GROUP group_name user_list
  • Example: Define the GROUP 'Researchers' consisting of users tom, jim, and bill and Reserve 1 OpticStudio Premium license license to the GROUP. 
    GROUP Researchers tom jim bill 
    RESERVE 1 zos_level1 GROUP Researchers
    RESERVE 1 zos_level2 GROUP Researchers

NoteEnsure that a USER only belongs to one (1) user GROUP.


  • Define a group of hostnames (computers) for use with any options. This option (HOST_GROUP) 
    is case-sensitive. Use the computer's machine name to identify each hostname. 
    HOST_GROUP group_name host_list
  • Example: Define the HOST_GROUP ZOSPREM consisting of Computer1 computer2 and computer3 
    HOST_GROUP ZOSPREM Computer1 computer2 computer3

Note: Ensure that each HostName only belongs to one 1 HOST_GROUP.


  • Allow a user or predefined group of users/hosts to use the license for this feature. Anyone not in an INCLUDE statement is not allowed to use that feature. EXCLUDE supersedes INCLUDE; conflicts between the EXCLUDE list and the INCLUDE list are resolved by the EXCLUDE taking precedence.
    INCLUDE feature type {name | group_name}
  • Example: Allow the GROUP 'researchers' to use an Opticstudio Professional license. 
    INCLUDE zos_level1 GROUP researchers

Notes: INCLUDE is required for USER_BASED or HOST_BASED features. The system administrator specifies which users are allowed to use the product, via INCLUDE, and the license limits the number of users that are included.


  • Allow a user or predefined group of users/hosts to use all license features served by the vendor daemon on the license manager. Anyone not in an INCLUDEALL statement is not allowed to use these features.
    INCLUDEALL type {name | group_name}
  • Example: Allow USER 'jane' to use all licenses for the vendor daemon on the license manager.


Limits usage for a group or user.

MAX 2 feature type {name | group_name}

Example: Limit the group ZOSPREM to 2 licenses for Opticstudio Premium.

MAX 2 zos_level2 GROUP ZOSPREM 



  • Deny a user or predefined group of users/hosts access to a license.
    EXCLUDE feature type {name | group_name}
  • Example: EXCLUDE the group NOZOS from using Opticstudio Premium .
    EXCLUDE zos_level2 GROUP NOZOS 


  • Deny a user or predefined group of users/hosts access to All licenses on the current FlexLM. If the type is not defined it will exclude all license features for all types (USERS, GROUPS, and HOST).
    EXCLUDEALL type {name | group_name}
  • Example: EXCLUDEALL the machine with HostName 'sky' from checking out any license features on the vendor daemon on the current license manager.


  • Reserve licenses for a USER, HOST or GROUP of users or hosts.

    Important Note: this will make the number of licenses reserved for the specified persons or group all the time, even when the Zemax software is closed on the client machine. If you want to simply prevent people from using Pro or Premium use EXCLUDE instead. 
    RESERVE number feature type {where type = name or group_name}
  • Example: RESERVE 1 license of OpticStudio Premium for USER 'jill'.   
    RESERVE 1 zos_level2 USER jill


  • Specify the expiration date of the license to be reserved to a predefined user/host or group of users/hosts. Allows you to specify a certain license based on it's expiration date if you have more than one.
  • Example: RESERVE 1 license of OpticStudio Premium with expiry date 31-jan-2022 to GROUP 'ZOSPREM'.  
    RESERVE 1 zos_level1:EXPDATE=31-jan-2022 GROUP ZOSPREM
    RESERVE 1 zos_level2:EXPDATE=31-jan-2022 GROUP ZOSPREM

Note: Ensure that the 'FEATURE' and 'EXPIRY DATE' are identical to that in the license file.



This keyword is available in the license file to release a license if Opticstudio or OpticsBuilder is closed but has left the license open on the server (in case of an application crash or change of network).

This will not time out licenses where Zemax software is open; the application is constantly trying to check in with the license server. 

  • Sets the time after which an inactive license is freed and reclaimed by the vendor daemon.
  • Minimum timeout is 3600 secs (1 hour)
    TIMEOUT feature{:keyword=value} seconds
    To timeout OpticStudio Professional in 1 hour, use this :

    TIMEOUT feature:zos_level1 3600


  • Same as TIMEOUT, but applies to all features in the license file. 



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