dsr.g2server.com has no NS records.
NS records for this zone are defined at g2server.com.
NS records for this zone are defined at g2server.com.
Question and response
Question
dig dsr.g2server.com. NS
Answer
The response has no answer records.
Authority
g2server.com. 1800 SOA ns1.geetoo.com. hostmaster.geetoo.com. 20190427 1200 600 1209600 1800
Additional
. 0 OPT ; payload 4000, xrcode 0, version 0, flags 0