Spurious failures in a dynamically updated to a sub /24 reverse DNS domain P.S.

[Mirsad Goran Todorovac]

Hello Tony,

Please excuse me, as I am a bit confused ...

I have tried to verify your findings, but I've found something awkward:

root at domac:~# host -t any 186.198.193.in-addr.arpa dns1.carnet.hr
Using domain server:
Name: dns1.carnet.hr
Address: 161.53.123.2#53
Aliases:

186.198.193.in-addr.arpa has SOA record dns1.CARNet.hr. 
hostmaster.CARNet.hr. 2021121001 10800 3600 2419200 14400
186.198.193.in-addr.arpa name server dns2.CARNet.hr.
186.198.193.in-addr.arpa name server dns1.CARNet.hr.
root at domac:~# host -t any 186.198.193.in-addr.arpa dns2.carnet.hr
Using domain server:
Name: dns2.carnet.hr
Address: 161.53.160.2#53
Aliases:

186.198.193.in-addr.arpa has SOA record dns1.CARNet.hr. 
hostmaster.CARNet.hr. 2021121001 10800 3600 2419200 14400
186.198.193.in-addr.arpa name server dns2.CARNet.hr.
186.198.193.in-addr.arpa name server dns1.CARNet.hr.
root at domac:~#

Does this mean that the delegation of the 
192/27.186.198.193.in-addr.arpa is in the zone 186.198.193.in-addr.arpa?

Moment ago it was all so clear to me, but now it seems hieroglyphic 
again :-(

Any idea? Thank you ...

Kind regards,
Mirsad

On 12/29/2021 6:57 PM, Tony Finch wrote:
> Mirsad Goran Todorovac <mirsad.todorovac at alu.unizg.hr> wrote:
>> I have recently implemented dynamic updates to a sub /24 reverse DNS
>> domain, 193.198.186.192/27.
>> I had upstream domain 192/27.186.198.193.in-addr.arpa. delegated from
>> authoritative servers.
>>
>> However, something still isn't right. In some reverse PTR addresses, the
>> resolver sees first redirection, and the second redirection, but somehow
>> fails to connect them in a reverse lookup:
> It looks to me like someone forgot to update the serial number on the zone
> 198.193.in-addr.arpa so your new delegation failed to propagate as it
> should have,
>
> The servers for 198.193.in-addr.arpa are:
>
> dns1.carnet.hr
> dns2.carnet.hr
> ns.ripe.net
>
> The first two know about the delegation for your zone
> 192/27.186.198.193.in-addr.arpa but ns.ripe.net does not.
> This is the cause of the inconsistencies that you observed.
>
> The SOA serial number for 198.193.in-addr.arpa is the same
> 2021052502 on all its nameservers.
>
> Tony.

Mirsad Goran Todorovac
CARNet sistem inženjer
Grafički fakultet | Akademija likovnih umjetnosti
Sveučilište u Zagrebu
-- 
CARNet system engineer
Faculty of Graphic Arts | Academy of Fine Arts
University of Zagreb, Republic of Croatia
tel. +385 (0)1 3711 451
mob. +385 91 57 88 355