I believe the Art-Net settings for this device are set onboard and not using the web-interface as this is not finished yet.

The Enttec box IS ArtNet compatible

The correct ethernet settings for artnet are:
2.0.0.x, subnet mask 255.0.0.y

or if you do not want your Artnet to be routable:
10.0.0.x, subnet mask 255.0.0.y

Hugh