fldsmtpe02.verizon.com has no NS records.
NS records for this zone are defined at verizon.com.
NS records for this zone are defined at verizon.com.
Question and response
Question
dig fldsmtpe02.verizon.com. NS
Answer
The response has no answer records.
Authority
verizon.com. 900 SOA ns-tmtr.verizon.com. sysmgr.verizon.com. 4917 900 600 4838400 900
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0