Ну, как по мне, так не все хорошо:
$ dig @
ns1.oss.spb.ru 59.138.83.in-addr.arpa soa
; <<>> DiG 9.10.6 <<>> @
ns1.oss.spb.ru 59.138.83.in-addr.arpa soa
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 49570
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
;; WARNING: recursion requested but not available
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;
59.138.83.in-addr.arpa. IN SOA
;; Query time: 35 msec
;; SERVER:
83.138.59.9#53(83.138.59.9);; WHEN: Tue Feb 04 14:31:32 MSK 2020
;; MSG SIZE rcvd: 51