Concurrent licenses are acquired by the license client (Surfer, Grapher, or Strater) over the network using UDP over IPv4 by default.  If your network only supports IPv6, you can still use concurrent licensing, but you need to set the license client PC with a Windows environment variable which tells the software to use IPv6 when communicating with the license server.

These steps are also valid for Microsoft DirectAccess environments which use IPv6.

Requirements: 

• The license server must have IPv6 enabled.
• The client PC must have IPv6 enabled and working.
• The client PC must be able to reach the license server on the IPv6 network over UDP.
• On the client PC, you must set a system environment variable: LSTCPIPVER = 6
• Setting the variable will force all Sentinel licensing on the client to use IPv6.  To switch back to IPv4, either clear the value or set it to "4".

Set the environment variable with a deployment or system management tool

1. Use your in-house PC management/deployment tools to set the system environment variable LSTCPIPVER value to 6 on the client computer(s).
2. Run Surfer or Grapher.
3. Click Select License Server in the <Product> Licensing dialog.
4. In the Golden Software License Server Selection dialog:
   If your IPv6 network supports UDP broadcast:
   1. Toggle Search for license servers on the local network and then click Search.
   
   If your IPv6 network does not support UDP broadcast:
   1. Toggle Enter license server name and then enter the license server's name or IPv6 IP address.

You can also set the client computer to connect to the license server automatically through the Windows Registry or using a Settings file.

Set the environment variable manually

1. Go to the client PC (the one running Surfer or Grapher).
2. Close Surfer or Grapher if currently open.
3. Add a new Environment Variable to force the licensing to use IPv6:
1. Navigate to Control Panel \ System and Security \ System
2. Click Advanced System Settings on the left hand side of the window.
3. Click the Environment Variables button on the Advanced tab.
4. In the System Variables section, click New.
5. In the New System Variable dialog, enter the values below:
   Variable name = LSTCPIPVER
   Variable value = 6
6. Click OK in each of the open dialogs.

System Properties dialog and the Environment Variables dialog overview. 

4. Open Surfer or Grapher.
5. Click Select License Server in the <Product> Licensing dialog.
6. In the Golden Software License Server Selection dialog:
   If your IPv6 network supports UDP broadcast:
   1. Toggle Search for license servers on the local network and then click Search.
   
   If your IPv6 network does not support UDP broadcast:
   1. Toggle Enter license server name and then enter the license server's name or IPv6 IP address.

See also:

• How To Apply License Settings Without User Interaction

Updated February 2022