Commit 21a08d6869d53c81268ef131eb88cb1dd74a71f0
2011-10-19T22:38:37
Empty DNS reply with OK status is another way to say NODATA. Sometimes DNS reply has nothing but query section. It does not look like error, so it should be treated as NODATA with TTL=0 as soon as there is no SOA record to deduce negative TTL from.