🚀 go-pugleaf

In article <19930118.004@erik.naggum.no>,
 posted to comp.mail.headers,
 Erik Naggum <enag@ifi.uio.no> wrote:
>
>Using the "for" clause doesn't require a database of recipients to messages
>and other expensive solutions because the loop detection information is
>kept in the message, and it doesn't rely on other sites (which the bogus
>"count'em, them drop'em" approach does).

Using the for clause properly isn't always easy. You've already alluded to
the problem with multiple recipients. Even for a single recipient, there are
potential difficulties.

RFC822 section 4.3.2 says that the "for" clause is used ``to record the
original [address] specification.'' However, it also (sections 4.1 and 6.1)
specifies the format, which must be
	local-part @ domain
Some reformatting of the address may be required if it does not arrive in
that format (e.g. it may be a source route or it may have come from
non-SMTP mail). Also, it is not necessarily guaranteed that the (envelope)
address will be unchanged after traversing a path that carries it through
several other systems, even if it is indeed a looping message. Comparison
of the possibly rewritten envelope address to a possibly rewritten version
of an earlier envelope address might not be meaningful.

If the format restriction were loosened (particularly also if the revised
specification permitted a list of addressees), it would be easier to use
this method.  Even so, the privacy issue remains a concern.

-- 
	Bruce Lilly		...uupsi!monymsys!sonyd1!blilly!bruce