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.