RLM has a built in method where a client can locate an on premises RLM server by sending a broadcast request to the local network (this is a similar concept to how DHCP works). Broadcast is enabled by default, and is the last attempt the client will make to locate a license on the network.
When is a broadcast message sent?
A broadcast message is sent to the network if all other attempts to checkout a license have failed. Basically, if all else fails the client will attempt a checkout via broadcast before giving up. You can read the full process of attempting to find a license in our documentation.
Disabling broadcast
Broadcast is enabled by default, though you can chose to disable it.
Server Side
When starting the RLM server (either manually or as a service) add the -noudp flag. This will mean the server will not listen for broadcast requests on the network.
Client side
This is controlled by the software provider (ISV).
ISVs: When building the RLM dev kit, modify your rlm_isv_config.c file and change rlm_isv_cfg_disable_broadcast to 1.
Multiple license servers
If you are running multiple RLM servers on a single computer, only one of the processes will be able to bind to port 5053 and listen for broadcast requests. If you would like broadcast requests to be available for all license servers, you will need to configure a single RLM server. See our KB: License Server Administration for Multiple Software Providers
