mars.ns.byteopt.com has no NS records.
NS records for this zone are defined at byteopt.com.
NS records for this zone are defined at byteopt.com.
Question and response
Question
dig mars.ns.byteopt.com. NS
Answer
mars.ns.byteopt.com. 86400 NS sns.speednet.bg.
mars.ns.byteopt.com. 86400 NS pns.speednet.bg.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0