dns.coustums.com has no NS records.
NS records for this zone are defined at coustums.com.
NS records for this zone are defined at coustums.com.
Question and response
Question
dig dns.coustums.com. NS
Answer
The response has no answer records.
Authority
coustums.com. 3600 SOA dns.coustums.com. hostmaster.coustums.com. 1756182457 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0