Perhaps I didn't understand something.
What I meant is that spammers can use a through-away domain or a temporary
subdomain (say "Mar282004.spamnet.net"), run a DNS server with enough
capacity to authenticate the day's spam-run. To block emails verified by
such a system, one would need to use some blacklisting technology against
Mar282004.spamnet.net or spamnet.net. But if you need a blacklist to enable
this message-body-authenticator technology, where's the value of the 'mba'
technology?
There are many other real-world problems with this - roaming senders,
centralized DNS database vs. decentralized outgoing MTA's, etc.
A system that relies to any extent on the DNS system should take into
account that authoritative slave name-servers cannot perform periodic, but
not necessarily frequent zone-transfers. Thus, there are propagation delays
between the DNS servers of any domain. The DNS system was not designed for
publishing real-time-like information.
Radu.
If MBA works as intended,
spammers won't use
it, because by using it, their domains would be promptly recognized and
easily blocked by most mail hosting providers. Assuming MBA is widely
adopted, a picky receiving MTA could choose to only accept
mba-authenticated
mails.
Ricardo
----- Original Message -----
From: Yakov Shafranovich <research(_at_)solidmatrix(_dot_)com>
To: Radu Hociung <radu(_dot_)asrg(_at_)ohmi(_dot_)org>
Cc: <spharion(_at_)directnet(_dot_)com(_dot_)br>; <asrg(_at_)ietf(_dot_)org>
Sent: Sunday, March 28, 2004 4:35 PM
Subject: Re: [Asrg] spf
LMAP-related discussions for SPF and other proposals have
moved to the
MXCOMP list (http://www.imc.org/ietf-mxcomp/).
Yakov
Radu Hociung wrote:
Unfortunately,
A spammer can just as well set this up. This system does not
discriminate based on the intention or identity of the sender.
Also, I think a good test to any anti-spam proposal is
this: Would this
be a sustainable model if it became mainstream?
Your approach relies on a lot of wasted resources at the DNS cache
level; imagine what would happen to Hotmail's caching DNS
servers if
they would cache two entries for every 2.5B spam messages
they receive
every day?
I didn't like the pop-ups.
I appreciate the effort, though; you may have something,
but it needs
more work.
Radu.
--
Radu Hociung
radu(_at_)ohmi(_dot_)org
-----Original Message-----
*From:* asrg-admin(_at_)ietf(_dot_)org
[mailto:asrg-admin(_at_)ietf(_dot_)org] *On Behalf
Of
*spharion(_at_)directnet(_dot_)com(_dot_)br
*Sent:* Saturday, March 27, 2004 7:10 AM
*To:* asrg(_at_)ietf(_dot_)org
*Subject:* [Asrg] spf
this is a tentative option to spf, but does not
seem to break forwarding:
http://nucleo.freeservers.com/mba/
have fun. gone, ricardo.
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