The DNS delegation for the in-addr.arpa.
domain works exactly the same way as for any other domain. The only difference is: instead of registering an in-addr.arpa.
, you get one whenever you are assigned an IP address pool.
The address pool 142.250.0.0/15
is assigned to Google and their name servers are authoritative for the domain 142.250.in-addr.arpa.
:
$ dig @x.arin.net. 27.4.250.142.in-addr.arpa. PTR +norecurse
; <<>> DiG 9.11.5-P4-5.1-Debian <<>> @x.arin.net. 27.4.250.142.in-addr.arpa. PTR +norecurse
; (2 servers found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6403
;; flags: qr; QUERY: 1, ANSWER: 0, AUTHORITY: 4, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
; COOKIE: fea615f1769369c875faa8fe5e1e28450e879031f36ee506 (good)
;; QUESTION SECTION:
;27.4.250.142.in-addr.arpa. IN PTR
;; AUTHORITY SECTION:
250.142.in-addr.arpa. 86400 IN NS ns3.google.com.
250.142.in-addr.arpa. 86400 IN NS ns1.google.com.
250.142.in-addr.arpa. 86400 IN NS ns4.google.com.
250.142.in-addr.arpa. 86400 IN NS ns2.google.com.
;; Query time: 151 msec
;; SERVER: 2001:500:31::63#53(2001:500:31::63)
;; WHEN: wto sty 14 21:44:53 CET 2020
;; MSG SIZE rcvd: 164
However they refuse to answer queries:
$ dig @ns1.google.com. 27.4.250.142.in-addr.arpa. PTR +norecurse
; <<>> DiG 9.11.5-P4-5.1-Debian <<>> @ns1.google.com. 27.4.250.142.in-addr.arpa. PTR +norecurse
; (2 servers found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: REFUSED, id: 48561
;; flags: qr; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;27.4.250.142.in-addr.arpa. IN PTR
;; Query time: 5 msec
;; SERVER: 2001:4860:4802:32::a#53(2001:4860:4802:32::a)
;; WHEN: wto sty 14 21:46:57 CET 2020
;; MSG SIZE rcvd: 54
So, you definitively should ask Google, why they don't provide PTR
records for their servers (or better they refuse to answer queries). Maybe they just forgot to add the 250.142.in-addr.arpa.
zone to their servers or some other misconfiguration.