In Netshell every host keeps its own zone on disk. nslookup gets answered by the nearest reachable server that owns that zone, out of hundreds of machines with their own filesystems, users, services and logs.
Get into the right box, edit the zone, and the rest of the network believes you. Nothing about that is scripted: it is the same resolution path the whole simulation runs on.
The new Network and DNS trailer is on the store page, along with a second one covering the general mechanics.
Follow the page if you want the next one to reach you, and wishlist if you want to hear from us at launch.