the new style for delegating a sub-class c network is to have
the ns for the class c return

d.b.c.a.in-addr.arpa cname d.net.c.b.a.in-addr.arpa

for example

133.39.14.65.in-addr.arpa -> cname 133.128.39.14.65.in-addr.arpa

since a.b.c.net.d is not a valid ip address, i'm not sure how to return
ptr records with ndb/dns for such a setup.

is this possible with ndb/dns (without extensive work)?

- erik