ns.abac.com has no NS records.
NS records for this zone are defined at abac.com.
NS records for this zone are defined at abac.com.
Question and response
Question
dig ns.abac.com. NS
Answer
The response has no answer records.
Authority
abac.com. 300 SOA ns.abac.com. hostmaster.abac.net. 2010052721 600 1800 604800 300
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0