Authored By

Alison Yates & Alissa Wilczynski


This article explains how to configure and activate a keyserver and client machine for use with an OpticStudio or Lensmechanix network license. Also included is a FAQ and some troubleshooting tips.


This article explains how to configure a license server and client machine for use with an Opticstudio or Lensmechanix network license. 

If you are configuring an OpticsViewer network license server or client, see this article instead

For instructions on how to install OpticStudio with an individual license, please refer to "Installing OpticStudio for the first time." 


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Prior to October 2016, Zemax sold black network USB dongles. To setup an Opticstudio license server and client for a Black USB network license (key serial numbers 22000 to 40999), see "Installing OpticStudio with a black USB network license." 

If your network license is already installed on your server, and you need information on configuring server settings, see the article "How do I monitor and control usage of the network key?."

Note that the network softkey or red USB license is worth the full value of the software. We recommend that you insure the network key for its full replacement value, and that the keyserver machine be kept in a secure room. If the key is lost or stolen, it will not be replaced without payment of the full purchase price unless ZPA is purchased or included with your license. See the Zemax Licensing Policies for details. 

Zemax network licenses make it easy to receive support renewal updates as they only have to be applied on the server machine. This also means the seats can be shared among a team without using transfer codes or trying to keep track of physical USB dongles for each user. The Red USB network key has the licensing information embedded in it. The softkey has no physical unit -- the license itself is attached to the keyserver computer through software. License check-in/check-out for offline use is supported with Softkey licenses, but not the Red USB key.

Preparing to install


Before installing the software, there are some simple concepts you must understand. The network key is installed on a machine called the keyserver. This machine hosts the license key and the software that makes the license available over your local area network (LAN). The keyserver can be any Windows machine on the network. It can be installed on Windows 7 Service Pack 1, 8.1, or 10 or any Windows Server 2008 R2 SP1 or newer Server operating system up to 2019. Note that "Core" versions of Windows Server are not supported. There is also no Linux support for the license server. The server requires 300MB drive space free for the software and only requires the same minimum RAM the OS requires to install. The keyserver needs to be visible on the network to all the machines that will want to use network licenses via "ping". 

Client machines are the machines that will run Lensmechanix or OpticStudio and use the network license. The client machines must be able to ping the keyserver in order for the license on the server to be seen.

For USB licenses and softkeys, Zemax uses the Gemalto (formerly Safenet) Sentinel LDK license technology, and communicates on port 1947 on your network. We highly recommend using this port if possible, as changing it has some side effects on the server, and requires each client machine to change the port manually as well. If you would like details on changing this port, see "What if Port 1947 is in use on my network?" in the Frequently Asked Questions section of this article. 

Tip: You cannot run multiple users of OpticStudio on the key server itself, though you may run one user on the server. The licensing is designed to assign network seats to client computers. See the FAQ at the end of this article.


Installing on the keyserver machine

The frist step to configuring your network license is to properly configure the keyserver machine that willl host the license. Doing this requires three steps: installing software and activating the license, checking the Windows firewall, and configuring the keyserver settings. The following sections describe these steps in detail. Note that in order to properly configure the keyserver, you must be logged in as an administrator on the key server machine.

Install and activate the license software

To install the license software and activate your license, take the following steps. 

  1. For installations on machines without internet access, you will need to first download and install the .NET Framework from Microsoft. As of May 2019, the minimum .NET version required is 4.6.2 but you may install a newer .NET framework if you like. Then proceed to step 2 and install the Zemax License Manager.
  2. Navigate to the OpticStudio Downloads page. Open the Resource Files section. Download and launch the Zemax License Manager (ZLM) installer. This application will allow you to view, activate or transfer the license as well as update your license when renewed or changed in the future. This installer package includes everything you need to install and manage a softkey or red USB license on a server. You may accept the default options, or choose an installation folder. 




  1. Activate your license:
  • For Red USB network licenses: After the license manager installation is complete, you may plug in your red USB dongle. The key is driverless, so Windows should automatically install the device. The key should light up with a red light if it is working properly. If the key does not light up, you may need to refer to the "How to troubleshoot red or green USB license issues" article. If the key is lit, move to Step 4.
  • Softkey licenses: First note that softkey licenses may only be activated once. After that, they need to be transferred away from the activated machine to a new machine. If you have a softkey license and your server is not connected to the internet: please visit this article for instructions to activate your softkey or complete a transfer from another machine offline. Then come back to this article and move to step 4 to complete the server configuration. If you have a softkey license and your server is connected to the internet, start by opening the Windows Start menu...Zemax License Manager...Zemax License Manager.

Note: Starting in May of 2019, Zemax begin shipping the Zemax License Manager Version 2 (ZLM V2), with a different user interface.  The instructions below will cover both versions of ZLM.

  • For the classic version of ZLM (Nov 2018 or older), select New key, input your activation code, and click Apply License. You should get a message of success. If the activation generates an error message, refer to "How to troubleshoot softkey license issues." 

  • For ZLM V2 as pictured below, select New License, and enter the License Number and Activation Code. Subscription Zemax licenses require individual software registration. If your software requires registration, two fields will automatically be displayed to enter your MyZemax email address and password. Before proceeding, ensure you have created your account at You will receive a confirmation message that your software has successfully activated.



  1. Verify your license is installed and working. After activation, you will be taken to the License Information or View License sections of the ZLM or ZLMV2, respectively. Verify that the Product, Support expiration, and Seats: Total match your activation email or purchase order. 


License Information



  1. After completing activation and verifying your information, we recommend reading the Zemax Licensing Policy. It provides details on how softkey licenses are locked to the machine, tips to avoid losing it, backing it up, and our policy on lost keys. 


Check or open the Windows firewall

The next step in the installation and configuration process is to check the Windows firewall. Normally the installation process opens the Windows firewall for you automatically. This section will tell you how to verify that it is configured properly.

  1. Open the Windows Firewall settings by clicking the Windows Start button and searching, "Firewall."
  2. Select the Windows Firewall app.
  3. Select "Allow an app or feature through Windows Firewall."


Allow an app or feature through Windows Firewall


  1. Check the list of applications. If “License Manager” or "Sentinel License Manager" is already on the list, then you may move to the next section of this article: Configure keyserver settings and security. If not, move to step 5 of this process to add it. 




  1. Click "Allow another app." If "Allow another app" is greyed out, select Change settings to enable it.




  1. Click Browse and open the C:\Windows\system32 folder.
  2. Select the hasplms.exe file from the list and click Open.




  1. The Zemax License Manager will appear on the Add an app window. Click Add to add the License Manager to list of exceptions. 




  1. The check boxes next to License Manager specify which type of network includes this exception. You may check any (or all) the boxes for Domain, Public networks, and Private networks. If you are not sure which you need, select all of the checkboxes. Tip: If the computer is not joined to a domain, the Domain option will not show up. 




  1. Ensure port 1947 is not blocked on your network firewall both for UDP and TCP, and that you can "ping" the IP address of the key server machine from other machines. Consult with your IT department if you are not sure.  

Configure keyserver settings and adding End-users in Myzemax

​The final step in configuring the keyserver machine is to configure its settings and security. Click on Launch Sentinel Admin Control Center (ACC). This is located at the top of the Zemax License Manager (Classic) or under Troubleshoot (ZLM V2). You can also get to the Admin Control Center by opening a web browser and navigating to http://localhost:1947.  


This will open your web browser to the the following page. If this page does not open, see "How to troubleshoot softkey license issues."


Click Sentinel Keys to see your installed Zemax license(s). Licenses can be identified by the Key ID field, which is also present in the Zemax License Manager. Note that Gemalto/SafeNet do provide licenses for other software, so you may also see non-Zemax licenses on this page. You can identify Zemax licenses using the Vendor field; Zemax's Vendor number is 114811. 

After identifying your license, you should be done with the basic server setup! If you have troubles with any of this process, you may contact Zemax support for additional assistance. For client configuration, proceed to the next section for client configuration. 




If you would like to further specify your server settings and security, select Configuration. You will see six tabs used to configure it. By default the licenses are available to anyone within your network. There is also no password or other blocks on changing settings in the Admin Control Center from other computers. You may configure security settings, log license usage, restrict users / computers from the license, and configure license Check Out (also known as Detachable Licenses) so client machines can use the software offline. For full details and instructions, refer to "How do I monitor and cotrol usage of the network license?." 

Now that your server is configured, move to the next section Adding End-users in Myzemax

Detachable licenses


Adding End-users in Myzemax

if you have activated a subscription license (subscription is normally in the Product Name in your activation email), you are required to add end-users to the license in Myzemax. End users will then be authorized to use the license, as well as access the Myzemax support resources. Perpetual licenses users do not require assigning end users to use the network license, but still need to be associated with the license for full Myzemax access. The License Administrator can add end users to the license and it will automatically send them a Myzemax invitation. The License Administrator is normally the same person who was emailed the software activation code or USB license. See the MyZemax FAQ for detailed information on adding end-users.


Installing on the client machine

Note: If you are connecting to a server that has a Black USB network license (for Opticstudio only, and license numbers 22000-40999), the below instructions do not apply. For help with configuring a client machine to locate a server with a black USB network license, refer to the article "Installing OpticStudio with a Black USB network hardkey." 

If you do you do not have a Black USB network hardkey, the steps below will guide you to installing on the client machine.

  1. Ensure that you are logged in as an administrator on the machine.

    Opticstudio licenses: Download the latest copy of OpticStudio from the OpticStudio downloads page and follow the instructions in "Installing OpticStudio for the first time."
    For lensmechanix licenses: Download the latest Lensmechanix release from the Lensmechanix Downloads page and install it. 
  2. Once installed, open Zemax License Manager from Start...Zemax Opticstudio...Zemax License Manager or Start...Lensmechanix...Zemax License Manager. Open the "License Information" or "View License" tab so see if it finds the network license automatically. If you do not see any licenses, skip to What to do if the license is not found automatically.
  3. Find the network license you wish to use and select Default or Set as Default. Some Zemax software will require individual software registration. If this is the case, a screen will pop up requesting your MyZemax email address and password. If your license administrator has already assigned you as an end-user, you should have received an email with the title "You have been assigned a Zemax License". Login with your MyZemax email address and password. You will see a confirmation message and then be returned to the View License page. The Default button will be blue, indicating which license is your default, and there will be a check mark indicating it has been activated.

    TIP: If you do not remember your MyZemax credentials, open, select Sign in, and select Reset your password. If you have not received an email about being assigned a Zemax license, or it says "not authorized" when logging in, you can request access to the license. Log into MyZemax, go to Licenses, and change the "My" dropdown to show your organization's name. Find the license number you want access to. Click it to show the License Administrator. Email them and request they add you as as an End User.

If you have multiple licenses available to you, you can change the default anytime. 



What to do if the license is not found automatically

If the key was not found automatically, follow the configuration steps below to help specify the network server where the license is hosted. 

  1. Open the Zemax License manager and select Launch Sentinel Admin Control Center (ACC). This is located at the top of the Zemax License Manager (Classic) or in the Troubleshoot tab (ZLM V2). You can also get to the Admin Control Center by opening a web browser and navigating to http://localhost:1947. If the Sentinel ACC gives an error message when opening, see "How to troubleshoot softkey license issues."

  2. Open Configuration...Access to Remote License Managers. Make sure Allow access to Remote Licenses is checked. We recommend you also select Aggressive Search for Remote Licenses. In the Remote License Search Parameters box, input the machine name of the network license server you would like to access. We recommend using the fully qualified domain name such as rather than just the machine name itself. It is not necessary to include http:// in the machine name. 

    Note that Zemax does not know your server name as we do not host your license. If this is at an educational institution for an optics class, check with the class instructor. If this is at a business, contact your manager or IT department to obtain the server information.
  3. Click Submit when done entering the server information.Note that there may be a delay of ~60 seconds before the key information is refreshed with the new settings. Check under Options...Sentinel Keys to see if the network license has become visible. If you see it, close the Admin Control Center and re-open Opticstudio. You are done! If the key remains unfound, continue to Step 4.


Sentinel Keys


  1. If the license key is still not found after entering the server information, try these options:
  • Restart the machine. That will ensure the licensing process has refreshed the settings.
  • Try using the IP address of the server rather than the machine name in the Remote License Search Parameters.
  • If you are logging in to a company network remotely via a VPN connection, your IT department may need to configure the VPN server to pass through traffic to the license server's IP address (Port 1947). Zemax cannot help you configure your company firewalls.
  • We also recommend verifying that your security software is not blocking access to the license software. Check your security software's logs to see if either the HASP_RT.EXE in the OpticStudio installation folder, or HASPLMS.exe in C:\windows\system32 has been blocked. Instructions for Mcafee Enterprise is covered in the Frequently Asked Questions section at the bottom of this page.

If you still cannot get Opticstudio to locate the license, feel free to contact Zemax support for help. 

​If you are a network administrator and would like to easily configure multiple client machines to use the same keyserver settings, see "Automate client computer configuration for softkey and Red USB key network installations" for more details. 

Zemax License Manager (Version 2) license check out

Opticstudio will automatically use a network license seat as long as it is connected to the network. If you need to leave the network you can check a seat out for use offline, assuming your server administrator has enabled this option. Note that using the license check out feature dedicates the license seat to your machine for 1 or more days (14 days is the default unless changed by the license server administrator). Therefore it's not recommended to use this feature unless you really need it. This will maximize the availability of license seats for others. 

Follow these steps:

  1. Close OpticStudio / Lensmechanix to ensure the license seat is not in use. 
  2. Launch the Zemax License Manager (ZLM)
  • For OpticStudio licenses, you can find the Zemax License Manager in Start...All Programs...Zemax OpticStudio.
  • For LensMechanix licenses, Open Start...All Programs...LensMechanix...Zemax License Manager.
  1. If your License manager shows a date of November 2018 or older at the top, skip to Classic License Manager license check out. For a Zemax License Manager dated May 2019 or later, move to step 4.
  2. Open the "License Information" tab. Looks for your network license - it will have "Network" in the product description. Make sure there is at least 1 seat "Available" or you will have to wait until another person stops using the license to check one out. 
  3. Click Check Out. If you receive any error messages during the check out, or if Check Out it is grayed out see "How to resolve errors when checking out a network license seat."


  1. If the check out was successful, an additional entry in the ZLM will appear with the following information. It will also be made your default license. The date by "Checked Out Until" is the date and time the license seat will expire and automatically stop working. The length of time is set by your network keyserver administrator. 



  1. Once the license seat is checked out, the client machine may be disconnected from the network. To return a license seat before it expires, simply press Check In. Note that your computer needs to be online and be able to see the same license number from which the seat was checked out. 



  1. Press OK, and you are done! 

Zemax License Manager (Classic) license check out

This applies to the Zemax License Manager from Opticstudio / Lensmechanix 18.9 or earlier (License Manager dated Nov 2018 or earlier).

  1. Locate your network license under License Information with "Network" as the product. Make sure there is at least 1 "Available" seat on the list.
  2. Click Check Out.




  1. If the check out was successful, an additional entry in the License Manager will appear with the following information about the checked out license seat. The date next to Checked Out Until is when the license seat will expire and automatically be checked back in to the server. The length of time is set by your network keyserver administrator. If you receive any error messages during the check out, or if Check Out it is grayed out see "How to resolve errors when checking out a network license seat."






  1. Once the license seat is checked out, the client machine may be disconnected from the network. To return a license seat before it expires, simply press the Check In button. Note that your computer needs to be back on the network and able to see the same license that was checked out, or the process will fail. 


For more details on the ZLM controls and information, you may also refer to the OpticStudio Help in The Help Tab...Information Group...License Manager.

Frequently asked questions

Can I have multiple users run OpticStudio / Lensmechanix on the license key server machine?

OpticStudio network licenses are designed using a client-server model. The key server is intended host the license itself, and the licensing assigns 1 seat per machine. Also, OpticStudio is designed to allow 2 instances of the application at a time. The key server can run a copy of OpticStudio for one user if you wish. Just be aware that using OpticStudio on the server for long optimizations or raytracing may tie up the CPU and may interrupt the license process for client machines. As a workaround to the above, you could install virtualization software such as VMware, then install Windows and OpticStudio within it. This also would allow you to limit RAM and CPU usage.

Do I have to worry about losing my softkey on the key server in case of hardware failure, theft, or a reinstall of Windows?

Yes. We recommend reading the Zemax Licensing Policies. It gives details on how softkey licenses are locked to the machine, tips to avoid losing it, backing it up, our policy on lost keys, and optional key insurance (ZPA).

What if Port 1947 is in use on my network?

Note that the keyserver and clients communicate on port 1947 on your network. This is because that port is not registered to any other known services. However, if that port is in use on your network, we can provide information to change it. Note that you will have to change the port on the key server and each client machine that will access the license server. Also, after the change the license will not be visible in the Zemax License Manager. Contact Zemax support to get instructions to change it and details. Please include your license key serial number (for example L000000) as well.

How do I configure multiple client machines with the server address, so users don't have to enter it themselves?

Normally, client machines will find the key server without entering the server name into the settings as long as they are on the same subnet. However, if you want to preconfigure the clients with a specific server name, or other settings, please see this article for details.

In the Zemax License Manager, there are fewer than the total number of available seats I expect to see. Why?

First, check on the server machine for licenses that have been checked out (detached) as well as open sessions. For instructions, read this link: "How do I monitor and control usage of the network key?." If the total number of seats is still not what you expect, this means that the server has not properly released a session after OpticStudio was closed. To resolve this, you can restart the Sentinel LDK License Manager service.

I checked out a license seat for use offline. When I restarted my computer, it was no longer available in the Zemax License Manager. What happened?

This is an issue that was discovered with OpticStudio 17.0 through 18.1. The vendor of our softkey licensing software released an update that addressed this issue. It was included in Opticstudio 18.4. More details on this issue in this article 

Client machines will not find the license server, or hang on the OpticStudio "splash screen" indefinitely. What can I do?

First, make sure that the firewall exception on the server is configured in step 5 of the server setup instructions above. Once you are sure of that, check the client machine has specified the name of the server in the What to do if the license is not found automatically section. If that is done, then your security software may be blocking access to the license software. We have seen both Trend Micro and McAfee block this. If you use Trend Micro, check its scan logs to see if either the HASP_RT.EXE in the OpticStudio installation folder (normally C:\program files\Zemax OpticStudio), or HASPLMS.exe in C:\windows\system32 has been blocked. If you use McAfee Enterprise, it's HIPS (Host Intrusion Prevention System) feature can block this. You can temporarily turn off HIPS to see if this is the case. On the client machine, perform the following steps: 

Right-click the McAfee icon in the system tray (by the time displayed at the bottom right). The Mcafee icon is normally a red shield with an M in the center. Navigate the menu to the Disable option.Select Disable HIPS protection. If this works, your IT department can whitelist the hasp_rt.exe process to fix it permanently. This file is located in c:\program files\Zemax OpticStudio.




Addendum: migrating your network license to a new server

This section provides a recommended procedure to move to a new server with minimal downtime and configuration. Note that if client machines have a checked out license seat at the time the license is moved to the new server, it will not affect them, as the checked-out licenses simply time out automatically.

  1. Install the Zemax License Manager software on the new server following the process at the beginning of this article. If you will be transferring a softkey license to the new server, and your old server has a Zemax License Manager dated before Sept 2016, you will want to update it before transferring it. The transfer process has changed in later versions. Alternatively, use the instructions to transfer the license without internet access instead.
  2. Copy the HASPLM.INI file from the current server to the new one. This file contains all the server settings from the Admin Control Center (user rules, detachable license settings, password, etc., as descrbied in "How Do I Monitor and Control Usage of the Network Key?"). It is located in C:\Program Files (x86)\Common Files\Aladdin Shared\HASP.
  3. Transfer the license from the old server to the new one. If using a Red USB license you may simply plug it in. If using a softkey license, follow one of the guides here: "Transferring and Updating a Softkey License (with internet)" and "Activate, Transfer, or Update a Softkey License On A Machine Without Internet Access."
  4. Test the license server is working with an an OpticStudio / Lensmechanix client machine. If you need to test the new license server before moving the license over, you may email They can provide you a 2 week temporary network license you can use. Note that you must have an active support agreement to receive a trial license. If moving a softkey license, test the transfer process between servers with the trial license to make sure it works and get used to the process. After you are done with the trial license testing you will want to remove it from the server to prevent users from accidentally using it after it expires. The easiest way to remove the trial license is to just transfer it away and discard the generated transfer code or h2r file.
  5. Let the users of OpticStudio know they may need to modify the settings on their client machines with the new server IP address or machine name. You can provide the new server information and a link to the instructions in this article under "What To Do If the License Is Not Found Automatically."  Alternatively you can provide them with a modified HASPLM.INI file with the new server information per the following article: "Automate Client Computer Configuration for Softkey and Red USB key Network Installations."


Addendum: restarting the Sentinel LDK license manager service to fix issues

This is useful if it's not practical to restart the entire client or server computer, and can be used to fix the following issues:

  • The license server or clients are not able to see the softkey license in the Zemax License Manager 
  • You change a setting on the keyserver and it doesn't take effect even after submitting changes
  • A license seat fails to check out on the client even though the "detachable license" feature is enabled on the server.
  • Releases sessions showing on the server that are no longer actually in use. Note that this does not release checked out licenses.

You may either open the Start menu, and search for services.msc, or open Control Panel...System and Security...Administrative Tools...Services and right-click on Sentinel LDK License Manager and select Restart.


Sentinel LDK License Manager


This article provided steps for installing the network license version of OpticStudio on both the server and client sides, as well as providing an FAQ and simple troubleshooting steps.

If your network license is already installed on your server, and you need information on configuring server settings, see this article for details. "How do I monitor and control usage of the network key?."