On Mon, 28 Feb 2005, David MacQuigg wrote:
Ultimately the simple basis for
deciding what address needs to be in the RFC2821.MailFrom is to
determine what address needs to be informed about
transmission-level problems (and, possibly, successes.)
Rather than change DSN routing for everyone, we should change the routing
on only the messages that are new and increasingly troublesome, spam
If the forwarder decides that they need to be informed about
transmission-level problems (including forgery), then they
put their domain in RFC2821.MailFrom, possibly using SRS or DBBF to
pass on DSNs up the chain. (A forwarder might also do this to
handle SPF checking clients that don't have a trusted forwarder list.)
Bounces. I would include in that category challenges from spam
filters. If it's not really spam, the Bounce-Path will get to the same
place as the Return-Path. If it is spam, we don't bother the Return-Path
with more spam.
This seems to be a point that you don't get. By using a DSN, then if
it is spam, we don't bother the Return-Path with more spam. This is
because DSN are *marked* and trivially ignored when coming from forged mail.
"Bounces", on the other hand are *not* easily ignored unless you
convince every MTA on the planet to use your new scheme.
DSN are already an existing feature with official documentation.
Most MTA already do them properly - and cause no problems (although
checking SPF before sending a DSN would save some bandwidth). Instead
of trying to get the rogue sites to use proper DSNs rather inventing
their own proprietary kind of "Bounce", you want to convince the entire
world to adopt a new standard to replace DSN - that does exactly the
same thing as DSN as far as you've mentioned so far.
Perhaps you didn't realize that DSNs from forged spam already do not in fact
bother anyone with a clue?
Stuart D. Gathman <stuart(_at_)bmsi(_dot_)com>
Business Management Systems Inc. Phone: 703 591-0911 Fax: 703 591-6154
"Confutatis maledictis, flamis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.