I'm trying to develop a discovery procedure based on how a 3rd party device works...
For discovery, I need to do a UDP broadcast to a specific port, and in turn
all of the devices out there, will send a UDP response from that port, back
to the (ephemeral) source port from the original broadcast.

For example:

192.168.1.149:port  -->  255.255.255.255:9999
192.168.1.149:port  <--  192.168.1.130:9999

How do I configure firewalld to enable such behaviour?

Thanks
Fulko