The license server is called sesinetd.

You must have "admin" rights (root, sudo) to be able to stop/start the license server.

Windows

You can start and stop the HoudiniLicenseServer in the Services area of Windows.

1. Control Panel -> Administrative Tools -> Services
2. The service HoudiniLicenseServer controls the license server program sesinetd.

Linux

1. Usage: /etc/init.d/sesinetd {start|stop}

Mac

1. Launch the Terminal from Utilities
   
2. To stop the license server: sudo launchctl unload /Library/LaunchDaemons/com.sidefx.sesinetd.plist
3. To start the license server: sudo launchctl load -w /Library/LaunchDaemons/com.sidefx.sesinetd.plist

If you receive an error saying /Library/LaunchDaemons/com.sidefx.sesinetd.plist: No such file or directory, please reinstall Houdini and choose Commercial Licensing. This will install the necessary license server files. Please refer to this page for other potential problems on MacOS.

When you restart the license server software on a centralized server machine, the remote clients will not lose their sessions for approximately 5 minutes of a failed heartbeat (or license check).