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Grant an Exception to the Network License Server in the Windows Firewall

Updated Dec 5, 2022

Reported In


  • Ultiboard
  • Multisim 8.0 Education
  • Multisim 9.0 Education
  • Multisim Student 9
  • Multisim 8.0 Professional

Issue Details

While installing the Network License Server (for the networked edition of Multisim 8 or 9), I receive the message: Connection to the license server failed. 

I am advised to give exceptions to the NLS and to the TCP Port indicated in the NLS.


When communicating to the NLS, any Firewall software installed in between the server computer and the client computer needs to grant an exception to the EWBNLSS application and the TCP Port indicated in the installation (the default is 1287). The following instructions apply only for the Windows® Firewall in case it is activated. For other Firewall software please consult your vendor's documentation.

Windows 7:
  1. Go to Start » Control Panel
  2. Click on System and Security
  3. Click on Allow a program through Windows Firewall under the Windows Firewall section

  4. Click on Change Settings on the Allowed Programs page
  5. Click on Allow another Program... on the Allowed Programs page

  6. Search for program name: Network License Server and click Network location types...
  7. Select all the network location types which apply. 
  8. Click Add
  9. Go back to the Windows Firewall from the Allowed Programs page by clicking on Windows Firewall in the file path address bar

  10. Click on Advanced Settings in the left-hand pane

  11. Select Inbound Rules 

  12. Select New Rule in the right column

  13. Select Port in the Rule Type Window and click Next
  14. Select the TCP radio button, type in the Port number you specified in the installation (Default is 1287) in the Specific local ports entry and click Next

  15. Select the Allow the connection radio button and click Next
  16. Select the network locations for which this rule applies, and click Next
  17. Give this rule a name and click Finish to add the new rule
The program should now be set up with an exception to the Windows 7 firewall, and the port used to communicate to the Network License Server should be open. 

Windows XP:
  1. Go to Start » Control Panel » Windows Firewall
  2. Switch to the Exceptions tab
  3. Click the Add Program... button
  4. Search for program name: Network License Server and click OK
  5. Now click the Add Port... button
  6. Give any name to the port configuration
  7. Type in the Port number you specified in the installation (Default is 1287)
  8. Select the TCP radio button and click OK
  9. Click OK to finish the Windows® Firewall configuration

Note: You may need to restart your computer for the changes to take effect.