PTR Configuration Question

Yann Debonne bind9-users at debonne.net
Thu Dec 2 17:01:10 UTC 2004


Stephane,

--On Wednesday, December 1, 2004 9:25 AM +0100 Stephane Bortzmeyer 
<bortzmeyer at nic.fr> wrote:

>> I just had my ISP (sbcglobal.net) delegate authority to me for reverse
>> DNS  entries for my DNS servers.  I kept getting errors when trying to do
>> a  reverse lookup for my IP address (67.122.54.85) and I noticed in my
>> logs  that the inquires have an extra number (80):
>>
>> queries: info: client 194.235.129.69#3291: query:
>> 85.80.54.122.67.in-addr.arpa IN PTR
>>
>> So, in my PTR record on my DNS server, I added the 2nd line:
>>
>> 85.54.122.67      IN      PTR     milk.purecreamery.com.
>> 85.80.54.122.67   IN      PTR     milk.purecreamery.com.
>>
>> And now all reverse lookups work correctly!  So, what is that "80"
>> digit,  and how did it enter the picture?!


> It comes from the upper zone (probably your ISP).
>
> ~ % dig +short 54.122.67.in-addr.arpa NS
> ns1.pbi.net.
> ns2.pbi.net.
>
> ~ % dig +short @ns1.pbi.net -x 67.122.54.85
> 85.80.54.122.67.in-addr.arpa.
>    ^^
>    They've apparently read RFC 2317 "Classless IN-ADDR.ARPA
>    delegation" in a very creative and unusual way.

Thanks for the response.  I just read your noted RFC and I don't really 
understand how they came up with this, but I'm curious if this is something 
worth me pursuing with them?  Is this "extra" lookup sloppy?  Or can I just 
leave it alone and move on?  :)

Thanks,

y 



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