# 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