On Mon, Feb 10, 2003 at 01:05:22AM +0100, Cliff Sarginson wrote:
...
> > I'm not sure DSNs are ever appropriate as "proof" of anything. Their
> > reliability is directly related to the proportion of servers that
> > support them. They can be useful. Certainly a failure DSN is very
> > useful.
>
> Oh I don't disagree with failure indications. But you get those anyway.
> But I think mail-systems of any use are built on the "Wells Fargo"
> principle .. "the mail must get through".
Then application of a little logic yields the result that Internet
email is not of any use, because the Internet email system as a whole,
including the SMTP protocol, is not built on "the mail must get
through."
Good admins treat correct delivery of mail (or non-delivery notices)
as an extremely high priority, and so does well-written MTA software.
However, there is a lot of mail system software in use on the Internet
that does not guarantee this and there are a lot of admins of Internet
systems who really don't care that much. For example, some MTAs may
acknowledge receipt of mail to the sending client before it is actually
written out to disk, and some admins may deal with some kinds of mail
system problems by deleting everything out of their mail queue in the
course of starting fresh. That makes the Internet as a whole unreliable
as a mail delivery system.
> An indication that it has not
> is good to know (maybe the mailman got shot by a bandit). An indication
> that it has is a bit overkill...just my view.
> But it is kind of a lot of baggage isn't it ?
It is; I agree DSNs are not really very useful. If you don't get
one, you know that either 1) the mail was not delivered, or 2) it was
delivered to an MTA which doesn't support DSNs. If you do get one (of
the delivered-to-their-inbox variety) then you know that 1) they will
see it when they next check mail (if they ever check their mail),
unless 2) it is accidentally or intentionally deleted before they
actually see it. This doesn't seem to add very many bits of
information IMHO.
Where this originally came in, IIRC, was discussing whether POPping
the mail could trigger an acknowledgement. That still leaves gaps: it
could be POPped by something like fetchmail and then lost before they
see it; it could be lost because they are using some kind of anti-spam
POP proxy which misclassifies it, etc. etc.
> Maybe one day when email achieves a greater legal status than it has
> now, then non-repudiation of receipt will start to matter.
I'm sure it will, but I think it will need to be implemented very
differently than it is now. For those purposes it would need to
include some kind of digital signature or hash on the content of the
email, to avoid various kinds of fraud.
-- Clifton
--
Clifton Royston -- LavaNet Systems Architect -- [EMAIL PROTECTED]
"If you ride fast enough, the Specialist can't catch you."
"What's the Specialist?" Samantha says.
"The Specialist wears a hat," says the babysitter. "The hat makes noises."
She doesn't say anything else.
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