I am sorry, didn't see the message until now. Did it workout?
I advise you to install this dota on github, since the one on Semtech is very old. Then you also don't need to configure it.
If you can't find the gateway try to nmap it. The vendor probably shows up as unknown. Like:
nmap -sP 192.168.178.1/24
If you need further help, please send a private message.