I am calling cloudflare API over https for reverse DNS lookup. Following is the URL for reverse dns lookup of one of the gmail server ip address, but cloud flare returns the status as NXDomain, which is wrong.
URL:- https://cloudflare-dns.com/dns-query?ct=application/dns-json&type=A&name=19.24.125.74.in-addr.arpa
JSON Reply:- {"Status": 3,"TC": false,"RD": true, "RA": true, "AD": false,"CD": false,"Question":[{"name": "19.24.125.74.in-addr.arpa.", "type": 1}],"Authority":[{"name": "125.74.in-addr.arpa.", "type": 6, "TTL": 60, "data": "ns1.google.com. dns-admin.google.com. 222769408 900 900 1800 60"}]}
If we look at the Authority key data, it shows the proper values which are expected to return for gmail ip address reverse dns lookup.
My assumption is if status is NXDomain, that represents CloudFlare doesnt have any record for the given IP, and this could be the case of some malware attack with DNS server being tampered for the requester.
~Ashish