Subject: RE: Testing Root A going away

From: "Christian Huitema" <[email-masked]>
Date: Sat, 30 Aug 2003 12:28:00 -0700

> Didn't J Postel run a test similar to that once <G>...
> 
> On a side note, how would you go about testing something like this ?

Obviously, cutting of the A root would have some pretty drastic
consequences. On the other hand, there are many computers that have no
business contacting directly the root servers. For example, in many
enterprises and campuses, computers are suppose to send their DNS
traffic to a configured relay. 

> What would be considered pass/fail metrics - well written applications
> vs. people doing silly and stupid things (ie. Would it be consisdered
a
> failrue that sobig fails because it was incorrectly written ?)

Looking at bugs in worms and using these bugs to squash the worms is
fair game. Another known bug is the SMTP Hello line always contains a
single token host name, instead of an FQDN. However, it is very likely
that such bugs will be corrected in a next release -- say, Sobig.G. 

The better question for the IETF is whether we should do something to
SMTP to make it less easy to send spoofed mail.

-- Christian Huitema

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From: shogunx <[email-masked]>
Date: Fri, 29 Aug 2003 17:17:53 -0400 (EDT)

> SMTP to make it less easy to send spoofed mail.

what, so one couldn't telnet in and send arbitrary mail?  include a
reversedns lookup in SMTP?  good luck on widespread implementation.

> -- Christian Huitema

sleekfreak pirate broadcast
world tour 2002-3
live from the pirate hideout
http://sleekfreak.ath.cx:81/

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From: Iljitsch van Beijnum <[email-masked]>
Date: Sat, 30 Aug 2003 22:54:34 +0200

On zaterdag, aug 30, 2003, at 21:28 Europe/Amsterdam, Christian Huitema 
wrote:

> consequences.

If that is the case then some people have been reading the relevant 
RFCs with their eyes closed. The only consequence should some sporadic 
short delays when a resolver asks the A but there is no answer so there 
is a timeout and one of the other root servers must be consulted.

> On the other hand, there are many computers that have no

How would that make a difference, other than that a central resolver 
can cache more efficiently? If a host needs a domain in a 
not-yet-cached TLD resolved, then someone somewhere has to ask one of 
the root servers for the information about this TLD, whether this is 
the host that needs the information or some other system working on 
behalf of this host.

> SMTP to make it less easy to send spoofed mail.

Well, draft-fecyk-dsprotocol-04.txt is in the RFC editor queue and this 
seems like a fair step in the good direction, without heaving read it 
in detail. So unless this is no good it should be shipped as and RFC 
and then the ball is in the vendors' court.

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From: Rick Wesson <[email-masked]>
Date: Sat, 30 Aug 2003 14:22:18 -0700 (PDT)

On Sat, 30 Aug 2003, Christian Huitema wrote:

[snip]

> traffic to a configured relay.

not realy. If 'A' stops answering you'll just ask questions of the others.
The issue is not if 'A' goes off the air, there are always other servers
to talk to.

-rick

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From: Dean Anderson <[email-masked]>
Date: Sat, 30 Aug 2003 18:03:59 -0400 (EDT)

> reversedns lookup in SMTP?  good luck on widespread implementation.

Reverse DNS lookups tell one nothing about the legitimacy of the email
being sent.  This has been hashed over on both namedroppers and DNSOP.

I also recently hashed out the Information Theoretic problems with
suppressing spam with a group of PhDs from one of my old companies.
After a great deal of arguing about the definition of Covert Channel (in
particular whether cooperation was required or not), it was determined (to
a high degree of confidence--but not to a formal proof) that spam is
indeed a covert channel, and therefore subject to the axiom that one
cannot prove there are no covert channels. I should note that during the
course of research I made to on the topic, which included reading a number
of original papers on the subject of Covert Channels, Side Channels, and
like concepts, I could find no written proof of this axiom, but neither
was it challenged as being untrue.

This confirms the intuition that digital signature schemes, and cost
schemes and other such suppression schemes cannot succeed.  Spam is
essentially dependent on the will of the sender, and given viruses, that
will can be subverted for many senders no matter what suppression scheme
is used. Spam can be detected, and stopped after detection, but it cannot
be made impossible to send.

The question is really whether SMTP has sufficient identification
information to track down an abuser, or infected user. The answer to this
question is "yes".  Even with an open proxy, the SMTP information will
identify the open proxy. The anonymity offered by the open proxy is
completely independent of SMTP.  However, to identify the abuser, one may
need law enforcement authority, or be willing to undertake a civil action
at some expense.  This is consistent with the PSTN, in which the identify
of a user can't generally be determined by another end user, but can
usually be determined using law enforcement authority.  Indeed, as with
the PSTN, some anonymity is appropriate.  One would probably not want to
allow end users to be able to identify another end user against their will
without a court order of some sort or some evidence of a criminal act.

		--Dean

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From: Keith Moore <[email-masked]>
Date: Sat, 30 Aug 2003 19:31:39 -0400

On Sat, 30 Aug 2003 22:54:34 +0200
Iljitsch van Beijnum <[email-masked]> wrote:

> Well, draft-fecyk-dsprotocol-04.txt is in the RFC editor queue 

that's odd.  the document claims to be a candidate for proposed standard, but
the I-D tracker says "not assigned yet" under "shepherding AD".  and I haven't
seen any Last Call announcement nor any request for it to be reviewed
in the usual fora that discuss email topics (e.g. ietf-smtp).

so I think it has a ways to go before publication.