authoritative rDNS

[Barry Margolin]

In article <mailman.1483.1381387501.20661.bind-users at lists.isc.org>,
 Jim Pazarena <bind at paz.bz> wrote:

> I set up a subnet on my server, complete with rdns, and ARIN has been 
> adjusted for my two dns servers (ns.qcislands.net & ns2.qcislands.net)
> 
> the subnet: 23.235.75.0/24
> 
> if you do a lookup of, for instance: 23.235.75.10
> and bounce that nslookup off of other dns servers, SOME say:
> Authoritative answers can be found from: <ns & ns2>
> 
> others, well, at least google 8.8.8.8 do not show anything as
> authoritative, altho the IP DOES resolve.
> 
> I am curious if 8.8.8.8 isn't trying, or instead, am I missing
> something which 8.8.8.8 considers incomplete and therefore 
> un-authoritative ?
> 
> I just want to make sure my setup is accurate. Thanks.

Including the Authority Section in a response is optional (unless it's a 
delegation or negative response). If you ask them explicitly for the NS 
records they show it:

$ dig @8.8.8.8 -x 23.235.75 ns

;; ANSWER SECTION:
75.235.23.in-addr.arpa. 21600 IN NS ns2.qcislands.net.
75.235.23.in-addr.arpa. 21600 IN NS ns.qcislands.net.

-- 
Barry Margolin
Arlington, MA