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

[Tony Finch]

Mirsad Goran Todorovac <mirsad.todorovac at alu.unizg.hr> wrote:

> Please excuse me, as I am a bit confused ...
>
> I have tried to verify your findings, but I've found something awkward:

Something has changed, because earlier I got:

; <<>> DiG 9.10.6 <<>> soa 192/27.186.198.193.in-addr.arpa @193.0.9.6
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 25229
;; flags: qr aa rd; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1
;; WARNING: recursion requested but not available

and now instead I get a referral:

; <<>> DiG 9.10.6 <<>> soa 192/27.186.198.193.in-addr.arpa @193.0.9.6
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 26187
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 1
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;192/27.186.198.193.in-addr.arpa. IN	SOA

;; AUTHORITY SECTION:
186.198.193.in-addr.arpa. 14400	IN	NS	dns1.carnet.hr.
186.198.193.in-addr.arpa. 14400	IN	NS	dns2.carnet.hr.

;; Query time: 22 msec
;; SERVER: 193.0.9.6#53(193.0.9.6)
;; WHEN: Wed Dec 29 23:35:20 GMT 2021
;; MSG SIZE  rcvd: 107

And the SOA serial number for 198.193.in-addr.arpa has bumped to
2021122901.

The actual delegation that was missing was for 186.198.193.in-addr.arpa,
not the delegation for your zone 192/27.186.198.193.in-addr.arpa

This error was partially hidden because of the shared carnet.hr
nameservers.

Tony.
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