_spf.directi.com has no NS records.
NS records for this zone are defined at directi.com.
NS records for this zone are defined at directi.com.
Question and response
Question
dig _spf.directi.com. NS
Answer
The response has no answer records.
Authority
directi.com. 180 SOA usc4.akam.net. syseng-senior.directi.com. 2018110849 43200 3600 1209600 180
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0