# apt-get install tcpdump

new shell 1 conmand(listen boardcast at iface esn33 from port 60000)
don't close shell,you will find relay board ip from this shell
# tcpdump -i ens33 udp port 60000

new shell 2 command(send boardcast to relay board)
# echo -en '\x05\xAA' > /dev/udp/224.0.2.11/60000