[1] qmail RFC violations (2005-12-14 00:00:05 +09:00 版) <http://ya.maya.st/mail/qmail-violations.html#8bitmime>

[2] RFC 6152 - SMTP Service Extension for 8-bit MIME Transport (2015-11-29 17:47:51 +09:00 版) <https://tools.ietf.org/html/rfc6152>

[3] RFC 1652 - SMTP Service Extension for 8bit-MIMEtransport (2015-11-15 20:58:46 +09:00 版) <https://tools.ietf.org/html/rfc1652>