smtp - What further happens after emails are received on SMTP ? Who Stores the email, is that SMTP?

Question

I am developing a customized SMTP server, it is almost complete too. Other SMTP can now contact with my SMTP and I can successfully recive what they send to me. But now I am thinking is it responsibility of SMTP to store the received email OR I will have to pass recived values to any other program that stores these values(such as to,from,data) of recived emails. If so then what is that program ? If not then who will store received values, is that SMTP ??

Answer 1

您编写的是邮件传输代理 (MTA)。将邮件投递到用户邮箱的软件称为邮件投递代理 (MDA)。MDA 可以是 MTA 的一部分（也就是说，您可以在您的服务器中编写知道如何传送到 mbox、maildir 等的代码，例如 Sendmail），或者它可以是一个单独的程序，如 procmail 或邮件投递。

Answer 2

如果您想在 Postfix（恰好是我使用过的唯一 SMTP 服务器）之后为您的自定义 SMTP 服务器建模，Postfix 使用位于 /var/mail 的 mbox 格式的 Postfix-maildrop 将电子邮件存储在文本文件中/[用户名]（在 Ubuntu/Debian 世界中，无论如何，这就是他们居住的地方）。

我在下面列出的另一个线程中找到了更多详细信息： https ://unix.stackexchange.com/questions/23277/where-does-postfix-store-email

Mbox 格式描述： http ://en.wikipedia.org/wiki/Mbox https://www.rfc-editor.org/rfc/rfc4155