u2.xundns.com has no NS records.
NS records for this zone are defined at xundns.com.
NS records for this zone are defined at xundns.com.
Question and response
Question
dig u2.xundns.com. NS
Answer
The response has no answer records.
Authority
xundns.com. 7200 SOA u2.xundns.com. nsadmin.xundns.com. 437896 3600 600 86400 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0