mx02.earthlink-vadesecure.net has no NS records.
NS records for this zone are defined at earthlink-vadesecure.net.
NS records for this zone are defined at earthlink-vadesecure.net.
Question and response
Question
dig mx02.earthlink-vadesecure.net. NS
Answer
The response has no answer records.
Authority
earthlink-vadesecure.net. 900 SOA ns-915.awsdns-50.net. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0