Since the confusion seems to have continued after the message to which I responded...
--On Tuesday, June 28, 2016 15:59 -0400 Chip <[email protected]> wrote: > My mistake NOT "bounces-to" rather "return-path" as in the > following snippet of campaign emails from Home Depot, Martha > Stewart and Sears: > > From - Mon Jun 20 08:43:03 2016 > X-Account-Key: account15 > X-UIDL: UID1962-1324328699 > X-Mozilla-Status: 0001 > X-Mozilla-Status2: 00000000 > X-Mozilla-Keys: > Return-path: > <[email protected] > otemail.com> RFC 5321 requires that an MTA create a Return-path: header field and copy the mailbox argument of the MAIL command into it before making delivery. If the MTA bounces the message, there will be no Return-path: header until the bounced message is delivered to wherever it was sent (see earlier note). Note that, unlike Envelope-to" and a number of other header fields that are made up by many MTAs, "Return-path:" and the conditions under which it is created are quite explicitly specified by RFC 5321 (and all of its SMTP predecessors) and are required, not discretionary. (Chris's explanation is otherwise correct, including the discussion of transitions into other mail systems (Section 3.7 of RFC 5321 may be further helpful in that regard.) --On Tuesday, June 28, 2016 23:03 +0200 Heiko Schlittermann <[email protected]> wrote: > Maybe this helps. > > https://en.wikipedia.org/wiki/Bounce_address FWIW, that article contains a lot of subtle errors, starting with 5321 being as clear as we could make it that the names of the relevant commands are "MAIL" and "RCPT", with "FROM" and "TO" as arguments. For those who are curious, the distinction became important when RFC 1425 was published in February 1993. > And reading the above article I just learned that my > terminology was wrong too, 'envelope from' I meant where I > used 'envelope sender'. There is a lot of sloppy terminology around, including in the SMTP spec itself. In my experience, unless complete pedantry has taken over, no one really cares as long as the intent is clear. If one cares, the precise terms are "mailbox argument to the MAIL command", as above, "reverse path", or "backward-pointing address". best, john (for identification, I'm the editor of RFC 5321) -- ## List details at https://lists.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://wiki.exim.org/
