Google Workspace で Gmail を使用できるようにする
https://support.google.com/a/answer/140034?hl=ja
1. whois
chukyo-u.ac.jp. 21600 IN MX 5 ALT1.ASPMX.L.GOOGLE.COM. chukyo-u.ac.jp. 21600 IN MX 1 ASPMX.L.GOOGLE.COM. chukyo-u.ac.jp. 21600 IN MX 10 ALT3.ASPMX.L.GOOGLE.COM. chukyo-u.ac.jp. 21600 IN MX 5 ALT2.ASPMX.L.GOOGLE.COM. chukyo-u.ac.jp. 21600 IN MX 10 ALT4.ASPMX.L.GOOGLE.COM. tohoku.ac.jp. 559 IN MX 10 ALT4.ASPMX.L.GOOGLE.COM. tohoku.ac.jp. 559 IN MX 10 ALT3.ASPMX.L.GOOGLE.COM. tohoku.ac.jp. 559 IN MX 5 ALT2.ASPMX.L.GOOGLE.COM. tohoku.ac.jp. 559 IN MX 5 ALT1.ASPMX.L.GOOGLE.COM. tohoku.ac.jp. 559 IN MX 1 ASPMX.L.GOOGLE.COM. ecei.tohoku.ac.jp. 12351 IN MX 1 zmmf01.star.net.tohoku.ac.jp.
2. history
gmail.com. 50 IN MX 5 gmail-smtp-in.l.google.com. gmail.com. 50 IN MX 30 alt3.gmail-smtp-in.l.google.com. gmail.com. 50 IN MX 40 alt4.gmail-smtp-in.l.google.com. gmail.com. 50 IN MX 20 alt2.gmail-smtp-in.l.google.com. gmail.com. 50 IN MX 10 alt1.gmail-smtp-in.l.google.com. googlemail.com. 600 IN MX 5 gmail-smtp-in.l.google.com. googlemail.com. 600 IN MX 10 alt1.gmail-smtp-in.l.google.com. googlemail.com. 600 IN MX 40 alt4.gmail-smtp-in.l.google.com. googlemail.com. 600 IN MX 30 alt3.gmail-smtp-in.l.google.com. googlemail.com. 600 IN MX 20 alt2.gmail-smtp-in.l.google.com.