Basic setup for the people not in the know

[rudymartin]

in case you haven’t done this already:

Unable to Filter the device from router (ONT)

as a shortcut, in cases like this, I suggest to forget about ACS at first. Just configure the device using the management web to get the configuration you want (in your case, an ARP filter). Once you are happy with it, download the router configuration from the maintenance page and take a look at it: you should be able to find a specific key which does the trick at the ACS side. If not, try configuring the device with obvious values on the required section then download the xml config again and …