The LM-X license server works in the same way as a FlexNet/FLEXlm license server. It serves licenses by listening on a specific TCP port and allowing you to check out licenses for network use or for borrowing, if enabled by your application vendor. Additionally, the server uses UDP for automatic server discovery. This enables applications to find the server without specifying a hostname.
Under Windows, you can run the license server in the console or as a service that runs in the background. Under Unix, you can run the license server in the foreground or background.