mx.nomail.kr has no NS records.
NS records for this zone are defined at nomail.kr.
NS records for this zone are defined at nomail.kr.
Question and response
Question
dig mx.nomail.kr. NS
Answer
The response has no answer records.
Authority
nomail.kr. 1800 SOA alexis.ns.cloudflare.com. dns.cloudflare.com. 2397024067 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0