+ ":cidr-delegation ((NET :bytes BYTES) ((TARGET-NET*) [TARGET-ZONE])*)
+
+ Insert CNAME records for delegating a portion of the reverse-lookup
+ namespace which doesn't align with an octet boundary.
+
+ The NET specifies the origin network, in which the reverse records
+ naturally lie. The BYTES are the number of labels to supply for each
+ address; the default is the smallest number which suffices to enumerate
+ the entire NET. The TARGET-NETs are subnets of NET which are to be
+ delegated. The TARGET-ZONEs are the zones to which we are delegating
+ authority for the reverse records: the default is to append labels for those
+ octets of the subnet base address which are not the same in all address in
+ the subnet."