ns1.centex.net has no NS records.
NS records for this zone are defined at centex.net.
NS records for this zone are defined at centex.net.
Question and response
Question
dig ns1.centex.net. NS
Answer
The response has no answer records.
Authority
centex.net. 900 SOA ns1.centex.net. please_set_email.absolutely.nowhere. 2010531304 10800 3600 2592000 900
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0