mx1.sparksystems.com.bd has no NS records.
NS records for this zone are defined at sparksystems.com.bd.
NS records for this zone are defined at sparksystems.com.bd.
Question and response
Question
dig mx1.sparksystems.com.bd. NS
Answer
The response has no answer records.
Authority
sparksystems.com.bd. 1800 SOA alan.ns.cloudflare.com. dns.cloudflare.com. 2397319027 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0