Subject: RE: namedroppers, continued

From: Marc Schneiders <[email-masked]>
Date: Fri, 6 Dec 2002 23:23:20 +0100 (CET)

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On Fri, 6 Dec 2002, at 13:41 [=GMT-0800], Fred Baker wrote:

> I think it was Steve Bellovin that suggested a procedure for reducing the
> utility of spoofing source addresses in emails; if not, it was me and I
> happened to suggest something his favorite algorithm fit into, by having a
> host in each mail domain (mailid.example.com) be able to assert that its
> domain had or had not sent an email within a given recent  time period
> whose MD5 hash, when divided by <vector of prime numbers> resulted in
> <vector of remainders>. I could write that up in an internet draft if folks
> think it makes sense. That would be a more global procedure that didn't
> require a PKI and only addressed spoofed addresses.

Spammers would be the first to set up your mailid host. They will have
had years of experience to find holes in the system before you've
convinced everyone to adopt or accept the mailid.

It might be easier to write a new protocol to succeed email, instant
messaging, mobile phones (something useful in itself) with built-in
abuse control from the start.

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From: Dean Anderson <[email-masked]>
Date: Fri, 6 Dec 2002 17:46:46 -0500 (EST)

Every domain would have to have a public key that the public could find.
Then every mailserver would have to check every message.

And spammers could still send spam, because they are authorized to send
email from some ISP, using that ISP's domain, and that ISP mailserver will
sign their email.

Spam isn't a security problem that can be solved technically.

Spam is the exact same problem as when Randy Bush harrasses someone by
abusing his privileges as administrator. There isn't a technical solution,
other than removing the privileges. Then the new administrator could abuse
the privileges, if they were so inclined.  There isn't a technical way to
give someone privileges that they can't abuse, if so inclined.

		--Dean

On Fri, 6 Dec 2002, Fred Baker wrote:

> At 08:28 AM 12/2/2002 -0800, Hallam-Baker, Phillip wrote:
> >The only way to resolve this issue properly would be to require every
> >submission to an IETF mailing list to be cryptographically signed (PGP
> >or S/MIME), to require the subscribers to register their signing key and
> >to then filter the mail sent out on the list so that only signed mail
> >gets through.
>
> I would be in favor of that, personally, as long as we can ensure that the
> appropriate signature facility (be it RSA, PGP, or whatever) is freely
> available to all who need to use it. The issue here is not us corporate
> types who have a business reason to buy the software, it is the students
> who often lack the funds. The big issue would be the procedures for posting
> one's key to the appropriate place - what is to stop a spammer from posting
> a key and sending the spam anyway? I'm not proposing a mechanism, but
> someone who is good at such things might well find it of value.
>
> It doesn't address the "off topic" issue. As you say, that could be left to
> a working group chair equiped with formal procedures developed by consensus
> within the work group or adopted by the working group from a more general
> place (ie, the IETF could suggest a procedure, and the WG could adopt it if
> it didn't feel another procedure would be better).
>
> I have had a private exchange, over the past few days, with someone who
> wished that the IETF would please document some good spam-elimination
> procedure, so that it could be used world-wide to completely eliminate
> spam. I think that boils down to "provide a global PKI" in this solution,
> and presumes that spammers are incapable of using one. That might be a
> great research topic. Too bad nobody has ever thought of it before; we
> could really use the outcome of that research. (OK, so it's a lame attempt
> at humor...)
>