I had a similar issue with a non-rockwell related device. I had the ability to see it, a few weeks later I tried with a new device and nothing.
An update modified my inbound rules. It didn't delete the old ones so simply allwoing bootP through my firewall did nothing.
I went to windows firewall -> advanced settings -> inbound rules -> and disabled the rule blocking bootP. (there was a Pair of them)
There was also a rule allowing bootP.
Sorry to necro an old thread but I use these threads religiously to solve my problems.