To avoid NetSim from asking the user to enter the Server IP address each time, during the application startup, perform the following steps:

1. You can also view or modify the environment variables by selecting System from the Control Panel, selecting Advanced system settings, and clicking Environment Variables.

2. Click on the New button to add a new environment variable.

3. Provide the Variable name as "RLM_LICENSE" and the variable value as "port number@server IP address"

For Eg:

4. Click on OK. 

5. Restart NetSim.

You will see that the NetSim application opens directly without the Licensing window.

Note: The Environment variable has to be reset if the license server IP is modified. That is, if the system running NetSim licenses is changed or if the IP address of the License server system is dynamic, the IP addresses may change.

The Licensing window may appear if the system is not able to communicate with the license server or if the licensing process isn't running on the license server machine.