ns15.bigwww.com has no NS records.
NS records for this zone are defined at bigwww.com.
NS records for this zone are defined at bigwww.com.
Question and response
Question
dig ns15.bigwww.com. NS
Answer
The response has no answer records.
Authority
bigwww.com. 600 SOA ns11.bigwww.com. hostmaster.hichina.com. 2026010913 3600 1200 86400 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0