esg01-iad3.rackspace.com has no NS records.
NS records for this zone are defined at rackspace.com.
NS records for this zone are defined at rackspace.com.
Question and response
Question
dig esg01-iad3.rackspace.com. NS
Answer
The response has no answer records.
Authority
rackspace.com. 300 SOA ns.rackspace.com. hostmaster.rackspace.com. 1773160089 300 300 1814400 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0