_spf.samsung.com has no NS records.
NS records for this zone are defined at samsung.com.
NS records for this zone are defined at samsung.com.
Question and response
Question
dig _spf.samsung.com. NS
Answer
The response has no answer records.
Authority
samsung.com. 300 SOA dns01.cst.ic. ssdomain.samsung.com. 2020085336 10800 3600 2419200 300
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0