The solution to support classless IP reverse mapping delegation was
not flexible enough and was not working in some case (though it
follows the latest RFC). It was using sub-nets. Now it is using range, so it
is much more flexible. Consider this work in progress.
When you create a new reverse zone, you can enter a range using the
x-y syntax. that's it. From now on, Linuxconf will update the the zone
if the IP number fits in that range. The zone will be named
for a a.b.c network.