smtpout.rackspace.com NS records

NS Authoritative DNS server
0s
smtpout.rackspace.com has no NS records.
NS records for this zone are defined at rackspace.com.
trace smtpout.rackspace.com NS records for rackspace.com

Question and response

Question

dig smtpout.rackspace.com. NS

Answer

The response has no answer records.

Authority

The response has no authority records.

Additional

. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0