1. whois
mm.mizuhobank.co.jp. 600 IN TXT "v=spf1 include:smp.ne.jp include:mktomail.com include:spf.securemx.jp include:_spf.qualtrics.com" " +ip4:210.162.178.137 +ip4:210.162.178.138 +ip4:210.162.178.139 +ip4:210.162.178.140 ~all"
2. history
mizuhobank.co.jp の SPFは設定なし。