Who Sets Up Reverse DNS (PTR) for a Domain: DNS Host or MX Host?

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I have the dns for a domain on GoDaddy and the MX configured for Gmail. All set up ok with spf, dkim and dmarc, and all passes all online tests, beside: intodns.com reports this error for the domain and marks it as severe:

Reverse MX A records (PTR) ERROR: No reverse DNS (PTR) entries. The problem MX records are: 27.4.250.142.in-addr.arpa -> no reverse (PTR) detected You should contact your ISP and ask him to add a PTR record for your ips

I have talked to gsuite tech support and they said I should ask Godaddy. At Godaddy they said they don't support rDNS as it was not required. Now who is responsible to set up this entry for me?

Best Answer

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.

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