The client half of the worked SMTP session — envelope first, headers inside DATA
The client half of the worked SMTP session — envelope first, headers inside DATA
Answer
EHLO client.example.org MAIL FROM:<[email protected]> RCPT TO:<[email protected]> RCPT TO:<[email protected]> DATA To: [email protected] Subject: lab notes Numbers attached tomorrow. . QUIT
Two RCPT TO commands, one To: header. The envelope decides delivery and the header decides display, so [email protected] appears in exactly one of them — that is BCC on the wire, with no Bcc header anywhere.
RFC 5321; RFC 1939; RFC 3501