On Wed, 21 May 2008, Robert A. Rosenberg wrote:
At 19:11 -0700 on 05/20/2008, ned+ietf-smtp(_at_)mrochek(_dot_)com wrote about Re: BATV
breaks rfc2821bis?:
FWIW, the ongoing problem we have with vacation messages is the "don't send
unless the recipient's address actually appears in the header" rule.
What Header? A mailing list (or BCC'ed) message sent to a user as the only
recipient at that domain, will usually have the user's address in a "for"
clause of a Received Header even though the address does not occur in a To or
Cc Header so it will still occur (and meet the rule criteria) if Received
Headers count.
Nope, the 'for' clause of Received headers is not part of the check. RFC
5230, section 4.5 has the full details, starting with:
"Vacation" MUST NOT respond to a message unless the recipient user's
email address is in a "To", "Cc", "Bcc", "Resent-To", "Resent-Cc", or
"Resent-Bcc" line of the original message. An email address is
considered to belong to the recipient if it is one of:
...
Ned's "ongoing problem" involves the "belong to recipient" part: people
want to send vacation responses to messages that reached them via
automatic forwarding from other sites, but the system doing the vacation
processing needs the user to tell it "this other address is 'me', so go
ahead and send vacation replies when that address is in the header".
Sieve's vacation extension gives users a way of doing that; actually
convincing users to fill it in is difficult.
Philip Guenther