smtp.directcom.com has no NS records.
NS records for this zone are defined at directcom.com.
NS records for this zone are defined at directcom.com.
Question and response
Question
dig smtp.directcom.com. NS
Answer
The response has no answer records.
Authority
directcom.com. 1800 SOA marge.ns.cloudflare.com. dns.cloudflare.com. 2395667111 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0