Skip to main content
Super User

You are not logged in. Your edit will be placed in a queue until it is peer reviewed.

We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.

10
  • 8
    I wish people made more real-world analogies here so others would understand what the physical equivalent is. The "sender" of an email is like the person handing the mailman the envelope; the "from" address is the one it's intended to be from. Like you could be a secretary sending on someone else's behalf, etc.
    – user541686
    Commented May 15, 2017 at 20:33
  • 21
    @Mehrdad No; the (SMTP) envelope sender address is like the return address on the outside of the envelope (where it gets sent if it can't be delivered), whereas the address in the From header is whatever you write on the piece of paper that you stick inside the envelope and that the mailman doesn't even know about.
    – user
    Commented May 15, 2017 at 20:37
  • I was thinking of the Sender: header when I wrote that, and it was just an example. Just saying it'd be nice to add an example like this to your answer.
    – user541686
    Commented May 15, 2017 at 20:44
  • @Michael What is the benefit of this? Why can't the email client display the "envelope"'s To/CC?
    – user656011
    Commented May 15, 2017 at 21:43
  • 3
    @SupremeGrandRuler Because the recipient information (in contrast to a possible Sender or Return-Path) is not contained in the email. Imagine the full recipient list was included, including the addresses the MUA got from the Bcc field (remember: SMTP (the envelope protocol) does not know about Bcc, it only knows about recipients) … That’d be a privacy issue (and a huge waste of space) not only on large mailing lists (operating by the same principle as Bcc does).
    – Jonas Schäfer
    Commented May 16, 2017 at 5:20