Subject: Result of test - authenticated email

From: "Hallam-Baker, Phillip" <[email-masked]>
Date: Thu, 5 Jun 2003 07:00:03 -0700

Harald points out some significant issues with pre-existing software.

I dispute his conclusion that a failed signature means that the message will
be thrown in the trash. Most filters (and certainly any compliant with the
criteria being discussed) would quarantine mail with a failed S/MIME
signature rather than discard.

The second point I would make is that the mailing list software is not
immutable. In fact mailing list software is likely to be rapidly upgraded to
support anti-spam filters very quickly since the manual anti-spam moderation
is a significant burden on the list admin.

The problem of broken, obsolete MUAs that do not support S/MIME cannot be
allowed to represent a veto. They have had plenty of time to upgrade, there
are plenty of free MUAs that work. I have a lot of time for deployment
problems when the people with the problem are not technologically
sophisticated and the only solutions are geekware. I have no time at all for
so-called technologists who refuse to eat their own dog food.

That said, yep, non-MIME based signatures may well be necessary. But this is
because the authentication model is diferent. We ae not authenticating at
the user level, we are authenticating at the domain level. Nobody is going
to block individual users of hotmail as spam senders, it is hotmail's job to
make sure that their customer's behave.

		Phill

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From: Keith Moore <[email-masked]>
Date: Thu, 5 Jun 2003 10:53:23 -0400

> signature rather than discard.

That's a bit like saying that "most ISPs" would quarantine mail from dubious
sources rather than simply rejecting it or discarding it.  I agree with you
that it's more robust to quarantine suspect mail than to discard it, but 
the latter practice is already widespread.

> is a significant burden on the list admin.

What you cite as "fact" may not be supportable.  When a dozen or more
intermediaries might be involved in the handling of a message from sender to
recipient, and when many of these intermediaries leave little clue about what
modifications they might have made to a message (firewalls and virus filters
typicaly don't even leave a received field), it's difficult to track down the
culprits, even more difficult to get the vendors of those products to fix
them, and still more difficult to get the fixes deployed.

> allowed to represent a veto. 

Perhaps not, but it does seem useful to realize that such MUAs exist.

> I have no time at all for

Welcome to the real world.  A huge number of so-called technologists are
forced to use Windows and Exchange even though they know better.

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From: David Morris <[email-masked]>
Date: Thu, 5 Jun 2003 12:22:03 -0700 (PDT)

> signature rather than discard.

Acknowledging and ignoring your other points for this response since I
agree, I think that once a system exists and is reasonably deployed, I
will quickly throw away 'non-signed' mail and non-whiltelisted mail. The
whole point is to get ride of spam, not let me put off evaluating it.

My phone is set to block caller id. Every once in a while, I call someone
who had a phone company option which blocks calls which don't have caller
id. I have to unblock caller id and call again (though recently, I got to
give permission to reveal my phone number interactively).

Frankly, if somone doesn't think what they have to say is important
enough to them to use the proper 'signing' process or perhaps the
responder override, I don't need to hear from them. I've encounted this
process once or twice and it was trivial to reply to the query. Even my
80+ year old aunt and uncle who have been using email for less than 2
years would grok it.

So I will toss or bounce unidentified origin mail. And I can assure you
that 'civilians' I know will do it even faster than I will.

Dave Morris