o2.ptr6137.gradual.us has no NS records.
NS records for this zone are defined at gradual.us.
NS records for this zone are defined at gradual.us.
Question and response
Question
dig o2.ptr6137.gradual.us. NS
Answer
The response has no answer records.
Authority
gradual.us. 1800 SOA rajeev.ns.cloudflare.com. dns.cloudflare.com. 2398437870 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0