ns2.alibabadns.com has no NS records.
NS records for this zone are defined at alibabadns.com.
NS records for this zone are defined at alibabadns.com.
Question and response
Question
dig ns2.alibabadns.com. NS
Answer
The response has no answer records.
Authority
alibabadns.com. 600 SOA ns1.alibabadns.com. hostmaster.alibabadns.com. 2017041916 3600 1200 3600 360
Additional
. 0 OPT ; payload 1280, xrcode 0, version 0, flags 0