Envelope Sender

Envelope sender or sender is the e-mail address passed as an MAIL FROM parameter during an SMTP handshake to RFC 5321.

The name Envelope (Envelope) is selected based on the envelope. As with the letter mail, only what is on the envelope is decisive for transport. The envelope sender corresponds to the sender, the envelope to the receiver. As with the letter mail, the sender is informed of the envelope (envelope sender) if his message was not deliverable - regardless of the sender in the message itself (bodyfrom: header). Bounce messages are sent with an empty envelope sender (<>) to prevent e-mail loops.

If the e-mail is stored in the mbox format, the envelope sender is included in the first line of the e-mail.

For example, sending a mail with the following SMTP commands: MAIL FROM:<absender@example.com> RCPT TO:<empfaenger@example.net>

creates the following line before the header of the received e-mail: Envelope-From absender@example.com Wed Jun 22 13:49:30 2005

The envelope sender is usually not displayed by e-mail programs, but can be made visible by special functions (eg showheader, show raw, ...). As with a letter you can also specify a wrong sender, so you should never rely on this statement. Only on Envelope-To can one rely, as long as the own Mailserver was not manipulated, because if Envelope-To had been previously manipulated, the e-mail would not have arrived. Weblinks Edit sourcetext

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