Subject: RE: [Asrg] Proposal for transition to authenticated email

From: "Tom Thomson" <[email-masked]>
Date: Thu, 1 May 2003 15:29:32 +0100

>If any of that were true, then it would be equally true of ISPs.
>Every SMTP message carries a practically unforgeable token identifying
>and authenticating the previous hop ISP.  If certificate authorities
>could be trusted to police customers that spend $100/year for a
>certificate, then ISPs could be trusted to police customers that spend
>$240/year for ISP service.
>
>
>Vernon Schryver    [email-masked]

That sounds like a nonsense argument to me (but carefully phrased to look
misleadingly plausible).

An ISP has a lot of costs to cover for its $200 per year that a CA doesn't
have to cover. That's why ISPs charge more for ISP service that CAs charge
for certificates.

Sometimes it seems to me that CAs do very little for their $100 per year, so
they should have spare cash they could use to pay for the policing; perhaps
that's an unfair view of CAs.

There are a very large number of ISPs, so many that we can't keep track of
them all so it's impossible to establish a trust relationship with them all,
so it woukld be no good pretrnding we can trust them to do the policing even
if they charged quite silly prices; there are far fewer CAs, it might be
possible to establish the trust necessary relationships.

I think the problem you have with proposals for authenticated email is a
simple one - the same problem you have with the RMX proposal:  you simply
don't want a reliable way of tying spam to its originator, you would rather
play with interesting methods of detecting spam and filtering it out. I
don't know whether that's because you don't see the usefulness of being able
to identify the originator, or because you find detecting bulk mail a fun
passtime, or because you think RFC 2821 is holy writ and not a comma may be
moved on pain of burning in hell throughout eternity for fould heresy and
blasphemy.  It has to be one of those three, I can't imagine another reason.

Spam is a social problem, not a purely technical one.  As with all
anti-social behaviour, being able to identify the perpetrators will be
useful.   I'm not claiming that that's the only thing we have to do, just
that it is an essential component of any proper answer to our problem.  So I
son't see it as helpful to sit back and snipe at every proposal that is ever
made that stands any real chance of delivering some sort of reliable
identification of the senders, particularly since most of the sniping you do
is based around misleading arguments like the one you produced above.

Tom

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From: Claus Assmann <[email-masked]>
Date: Thu, 1 May 2003 08:47:25 -0700

On Wed, Apr 30, 2003, Daniel Feenberg wrote:

> Wouldn't TLS traffic go via port 465 in most cases? I don't think any

No. I'm talking about STARTTLS, not smtps.

> of the proposals here are intended to regulate anything except port 25.
> 
> In any case, for TLS wouldn't you need explicit cooperation from the the
> remote MTA, in which case the pair of you could agree to use a port other

There is a standard, why do you want to invent something new?
It's hard enough to get people to use this standard, no need
to make it even more complicated...

> than 25. Or is there a way to use TLS when communicating with strangers?

Yes.  Please see RFC 2487 (SMTP Service Extension for Secure SMTP
over TLS).
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From: "Eric D. Williams" <[email-masked]>
Date: Fri, 2 May 2003 10:49:51 -0400

Has anyone taken a look at the headers of the asrg mailing list messages to 
their machine?  I just did, and think that we could use them as sort of a basis 
argument for eMail list handling of maillist traffic and/or originator 
identification.  What bothers me is the boundary where origination is defined. 
 I could 'take as gospel' the header information and validate origination based 
on that OR, perform checks against some not yet defined MTA MAC scheme, or 
perform content inspections, etc, etc...  While all of those are viable (albeit 
may be not practical methods in all circumstances) each has it's own 
shortcomings.

1) Message headers can be forged up to the last hop.
2) MTA MAC checks could be CPU intensive for large sites and/or 
non-approachable by small sites (border MTA's)
3) Content Inspection same as 2, but with the added twist of third party 
reliance or roll-your-own.
...

You get the point?  Focusing on single point solutions to multi-vector problems 
is hard (IMHO ill-advised) on its face.  Perhaps we are all correct, in fact 
maybe the framework or architecture of the system is the most salient 
discussion and not the implementation specifics.  I am not trying to just shoot 
my mouth off here, but it seems that many threads of discussion get too deep 
too fast and we may be missing the big picture.

my $.02

-e

On Thursday, May 01, 2003 10:30 AM, Tom Thomson 
[SMTP:[email-masked]] wrote:
8<...>8
> blasphemy.  It has to be one of those three, I can't imagine another reason.
8<...>8

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From: Scott Nelson <[email-masked]>
Date: Fri, 02 May 2003 10:02:43 -0700

At 10:29 PM 5/1/03 -0400, Ken Hirsch wrote:
>From: "Vernon Schryver" <[email-masked]>
>> > From: "Ken Hirsch" <[email-masked]>
>> > I think any general solution will depend on identity verification, which is
>> > a key part of my plan.  Anything else has to build on that. ...
>>
>> That is a religious view in the sense that it is based on unquestioned
>> and unquestionable assumptions or axioms that cannot be reconciled
>> with the differing religious views or axioms behind SMTP.  You assume
>> that accepting mail from perfect strangers is not worthwhile, but SMTP
>> is built on the opposite assumption.
>
>That's not it at all. I don't have any problem accepting mail from 
>strangers.  But
>without identity if you shut down a spammer one place he will pop up in another.
>I've thought about this a lot and I don't think there's a way around it.
>

Minor quibble here:  Stranger != Anonymous.
A system could, in theory, only accept email non-anonymous sources
and still accept email from non-anonymous strangers.

What value there is to accepting email from anonymous sources
is a different question from what's the value of accepting email 
from strangers.  
Which is not to say they aren't both religious questions
(in the sense Vernon was using).

Scott Nelson <[email-masked]>