I guess what they did works but it makes some of valid ip addresses unavailable.

I always suspected this was possible but having it demonstrated is excellent. I would assume this would be of most benefit on an OpenWRT box which _does_ support hardware offload!

I miss when this kind of content would've just been two paragraphs and a config snippet.

(also, this isn't a "Show HN")

I mean at this point just ditch the Unifi? You have a much more capable gateway in play now that needs to have equal to greater throughput than the one you are bridging for.