From: "Alan DeKok" <aland(_at_)freeradius(_dot_)org>
...
That's all true, and as I've been pointing out for many years, those
are all necessary and desirable characteristics of SMTP.
Then why are we wasting our time in ASRG? Why not just give up, and
live with a broken protocol which is designed to be easily abused?
Again, it is not the protocol that is "broken" and "easily abused,"
but the design goal or problem statement. If you really think that
SMTP is hopeless as protocol, then you should certainly quit because
this mailing list is not about tossing the design goal of public
mailboxes. The rationalization for this mailing list is that there
are things that can to deal with spam without giving up on public
mailboxes. That rationalization is justified by the many mailboxes
that receive less than 1% of the spam sent in their direction and
fewer than 1 spam/day.
...
(Some of the other troublesome characteristics are somewhat
distinct. For example, without "traffic amplification" this mailing
list could not exist.)
I disagree. The "traffic amplication" of lists is an MTA which accepts
one message, and chooses to send copies to multiple destinations. The
"traffic amplification" is RFC 2197 comman pipelining. Section 4.2,
number (2) appears to allow multiple RCPT TO: with one DATA, and MTA's
allow this.
...
The relatively new notion of SMTP command pipelining is not required
for multiple Rcpt_To commands in a single SMTP session. Command
pipelining is about not waiting for responses to some commands in the
envelope until all of them have been sent. Multiple Rcpt_To commands
have been a valuable optimization for MTAs hosting large mailing lists
for approximately forever.
The "spam gain" obtained by using multiple Rcpt_To commands and an
open relay is much less valuable on the modern Internet. A case study
is the artauction/art-server/artserver/etc. spammer that apparently
uses much of a T3 to send millions of 5-8 KByte messages, one SMTP
session per spam target. He has been at it for a long time.
Vernon Schryver vjs(_at_)rhyolite(_dot_)com
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