Applicable Versions
NetSim Academic  
NetSim Standard 
NetSim Pro  


Applicable Releases
v10v11v11.1



This article explains how you can enable the RLM server to get license server to work through the firewall.


If you have set up your floating license server and pointed the client machines to the license server correctly, but the product is still not able to get a license then it could be that a firewall on the server is blocking legitimate requests for a license.


A typical licensing error message caused by a firewall is:


Communications error with license server (-17)

Connection refused at server (-111)


In order to fix this, you need will need to change your firewall settings to allow the license server software to communicate through the firewall.


There are two firewall exception methods on Windows, Program Exceptions and Port Exceptions.  The Program Exceptions is the easiest method to turn on on the server system.


Step 1: From the Windows Start menu, click Control Panel > System and Security > Windows Firewall and then click on the Advanced Settings link on the left hand side.





Step 2: Select Inbound Rules in the left-hand panel and click New Rule

Step 3: Select Program and then click Next.

Step 4: Select This program path and then browse to the location of the RLM server:

<NetSim_License_Server Path> rlm.exe.




Step 5: Click Allow the connection and then click Next.  

Step 6: Select all the checkboxes that apply to the rule. Domain, Private, and Public.

Step 7: Click Next and enter a meaningful name for the rule, such as RLM_SERVER and then click Finish to complete the process.


Step 8: Start/ Re-Start the NetSim RLM Server.