On Tue, Oct 14, 2003 at 05:53:34PM -0400, Eric S. Raymond wrote:
I see a larger problem. What if the registrars worry that incorrectly
advertising a domain as verified when it is not (or vice-versa) could
open them to legal action?
If they care more about lawsuits from their users than about
stopping spam then that tells us something about their attitude
that can be used in a spam weighting system.
Ideally, we're looking for data that doesn't require the registrar to make
a potentially actionable judgment.
Tying a domain to an owner is just about the minimum we can ask.
If we don't want to ask the registrar to do that job then we
have to ask someone else, like Verisign.
What SPF does is hijack DNS and use it as a sort of poor mans
verified identity on the net. It's the same service that
sellers of SSL certificates perform, but we are doing it
on the cheap (and likely not as well). Instead of the
crypto-based key you get to point at some SMTP servers
that you (hopefully) control. Instead of checking the sig
we have the relative uncrackability of the TCP sequence
number which authenticates the sending SMTP server to the
reciever.
You can imagine alternative systems in two dimensions.
In one we still use DNS for identity, but let people invent
real crypto certificates, which they publish using the DNS.
This gives us real advantages in the area of forwarding and
flexibility etc., but means more software changes (auto-signing
and auto-signature-checking SMTP servers).
In the other direction you can imagine some system where the
registrars are forced to upgrade their ID checking to the same
level Verisign etc. use when issuing certificates.
SPF -------- SPF with ID-checking registrars
| |
| |
| |
| |
Autosigning ----------Autosigning SMTP servers with
SMTP servers Verisign-checked or registrar-
with DNS-published checked certificates.
keys
Moving South solves these problems:
* .forward files
* Single trustworthy user in untrustworthy domain
* Spam funnelled into mailing lists
* Removing authentication from mails retroactively
to combat compromised machines (eg. for POP clients
that can check the certs themselves).
* Not having control of the SMTP server that you are
forced to use.
* Any form of store-and-forward mail (TCP sequence info
is lost, but signed mail is still signed).
* Travelling mailman problem
Moving South also causes these problems:
* More changes to SMTP servers
* Have to accept mail before deciding if it is spam
(inevitable anyway I feel).
Moving East solves this problem:
* Throwaway domains
Moving East also causes this problem:
* Expense of someone doing those ID checks
--
Erik Corry erik(_at_)arbat(_dot_)com
A: Because it messes up the order in which people normally read text.
Q: Why is top-replying such a bad thing?
A: Top-replying.
Q: What is the most annoying thing in email?
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