spf01.tokai.or.jp has no NS records.
NS records for this zone are defined at tokai.or.jp.
NS records for this zone are defined at tokai.or.jp.
Question and response
Question
dig spf01.tokai.or.jp. NS
Answer
The response has no answer records.
Authority
tokai.or.jp. 600 SOA dns0.tokai.or.jp. postmaster.tokai.or.jp. 202508001 18000 300 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0