mx61.ntts-idc.net.sg has no NS records.
NS records for this zone are defined at ntts-idc.net.sg.
NS records for this zone are defined at ntts-idc.net.sg.
Question and response
Question
dig mx61.ntts-idc.net.sg. NS
Answer
The response has no answer records.
Authority
ntts-idc.net.sg. 300 SOA ns1-09.azure-dns.com. azuredns-hostmaster.microsoft.com. 1 3600 300 2419200 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0