[sudo-sys] can't reach door computer

[Yardena Cohen]

Did something happen to the omni door computer? I can't reach it over
the network, even from within the building. It appears to be working,
letting people in. I tried looking at the box, but couldn't make sense
of the mess of cables. Maybe an ethernet got disconnected somewhere?

The rest of the network is fine. Other devices on that subnet and that
interface are reachable, but:

$ ip neigh | grep 100.64.64.11
100.64.64.11 dev enp3s2  FAILED