zuntan02 https://blog.hatena.ne.jp/zuntan02/ zuntan02のはてなブログ https://zuntan02.hateblo.jp/ detail.chiebukuro.yahoo.co.jpRFC5321より http://www.ietf.org/rfc/rfc5321.txt2.3.5. Domain Names Only resolvable, fully-qualified domain names (FQDNs) are permitted when domain names are used in SMTP. In other words, names that can be resolved to MX RRs or address (i.e., A or AAAA) RRs (as discussed in… 190 <iframe src="https://hatenablog-parts.com/embed?url=https%3A%2F%2Fzuntan02.hateblo.jp%2Fentry%2F2017%2F09%2F13%2F145649" title="無知メモ：MXレコードが無い時はAレコードを見る - zuntan02のはてなブログ" class="embed-card embed-blogcard" scrolling="no" frameborder="0" style="display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;"></iframe> Hatena Blog https://hatena.blog 2017-09-13 14:56:49 rich https://zuntan02.hateblo.jp/entry/2017/09/13/145649 1.0 100%