Understanding reverse DNS better

Tue Jan 25 14:38:43 UTC 2011

+1, also a quick check to make sure your name servers are actually set 
can be done with host..  host -t ns 0.168.192.in-addr.arpa


On 25/01/2011 10:34 PM, Jared Mauch wrote:
> I suggest doing something like:
>
> dig +trace -x 204.42.254.5
>
> You can watch the delegation authority for the in-addr at each stage.
>
> - Jared
>
> On Jan 25, 2011, at 9:30 AM, Caleb Tennis wrote:
>
>> We have a /24 from one of our upstream providers that we handoff to a customer.  The /24 has been SWIPd to us, and we have nameservers setup with ARIN against that record.
>>
>> Twice now this information has just "disappeared".  That is, if do reverse DNS lookups, they returns nothing, whereas they were just working fine earlier.  If you do an NS lookup on the block, it returns nothing.  The /24 blocks immediately surrounding us continue to work just fine.  If we do a lookup directly against our nameserver, it works just fine.
>>
>> It's like the nameserver information against that reverse DNS is just magically gone.
>>
>> The ARIN record looks good, nothing has changed. Last time, our upstream resubmitted the info so it would repopulate, and it started working again soon there after.  I admit to not being the smartest one with how these records work: is the problem with the upstream, or ARIN's database, or is there not enough information to tell?
>>
>> Thanks,
>> Caleb
>