On 19/08/14 13:12, Bazy V wrote: > $ORIGIN 20.172.IN-ADDR.ARPA. > > 0.220/24 NS ns2.sub.test.com You don't need to do this. You just need: $ORIGIN 20.172.IN-ADDR.ARPA. 220 NS ns2.sub.test.com. RFC 2317 is only need for /25 and longer.