banni.kohoan.com has no NS records.
NS records for this zone are defined at kohoan.com.
NS records for this zone are defined at kohoan.com.
Question and response
Question
dig banni.kohoan.com. NS
Answer
The response has no answer records.
Authority
kohoan.com. 3601 SOA dns1.registrar-servers.com. hostmaster.registrar-servers.com. 1771235123 43200 3600 604800 3601
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0