== 参考文献 ==
* [https://server-setting.info/debian/debian-postfix-setting.html Debian(Ubuntu)で postfix を使ってみる]
* [https://jsapachehtml.hatenablog.com/entry/2014/01/26/184604 ubuntuでSMTPサーバの構築(SMTP-AUTHの設定)]
* [https://centossrv.com/postfix.shtml メールサーバー構築(Postfix+Dovecot)]
== 脚注 ==