spf-discuss
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Re: SPF will solve spam and punish spammers

2004-07-22 11:52:12
On Thu, 22 Jul 2004 11:36:16 -0700, Jonathan Gardner
<jonagard(_at_)amazon(_dot_)com> wrote:
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SPF does indeed solve the spam problem. SPF will bring spammers to justice.

* SPF Publishing Leads To Liability

SPF publishing claims legitimacy.
Legitimacy implies responsibility.
Responsibily is liability.
Liability brings spammers to justice.
Brining spammers to justice will solve the spam problem.

SPF publishing claims legitimacy because you make three assertions:
- These servers are illegitimate - They never send legitimate mail
? These servers are unknown - They may or may not send legitimate mail
+ These servers are legitimat - They always send legitimate mail

Some people are arguing that legitimate sending MTAs don't send legitimate
mail. That is absurd. If a sending MTA sends illegitimate mail, it is not
legitimate. If you are stuck in a situation where you are using a sending
MTA that cannot be trusted, don't tell us to trust it. Instead, publish it
with '?'.

Legitimacy implies responsibility. When I tell you that a sending MTA is a
legitimate sending MTA for my domain, I am held responsible for that mail.
I told you that it is mine.  I must ensure that that sending MTA is working
properly, that it is secure, and that the mail it sends is indeed
legitimate. If I can not be responsible for it, I must not claim it is
legitimate.

Responsibility is liability. If I am responsible for something, and that
something causes harm or damage, I am held liable for that harm or damage.
The only way I can escape liability is proving that I did everything to the
best of my knowledge and ability to prevent the damage. I can also transfer
liability to someone else - for instance, a hacker or a virus writer - who
caused damage to me and thus caused the other damage. This is all very
dependent on your country's laws. However, I believe that most laws are
similar: responsibility is liability.

When we have liability, we can start to prosecute and execute justice on
spammers the same way we prosecute other people who commit crimes. With an
effective method of prosecution, with laws that can be executed justly, the
spam problem will disappear.

* Only Email With Responsible Party Will Be Accepted

Now I make another assertion, equally important: Eventually, the only email
that will be accepted is email that someone has claimed responsibility for.

SPF is only a way to claim responsibility by the sending MTA. DomainKeys
allows you to claim responsibility even though the sending MTA isn't
trusted. There will be other ways in the future.

Legitimate senders want to claim responsibility, for two reasons.
(1) They don't want illegitimate mail to be accepted as theirs.
(2) They want to show how responsible they are and how well they can be
trusted.

Those areas where responsibility isn't clear - for instance, mail sent under
SPF NEUTRAL or SPF SOFTFAIL, or without DomainKeys, etc...  - will be the
last home for spammers. Spammers dare not enter into the responsible mail
domain, unless they want to be held accountable. Those that do will be
punished.

Eventually, as all the non-spammers leave the responsibility-free zone, and
only spammers are left, no one will want to receive mail from the
responsibility-free zone. These messages will be rejected at all ends of
the spectrum. It will become a realm with plenty of senders, but no
receivers.

The only mail that will survive is mail that has a responsible party.

QED.

I invite people to point out holes in my logic.

I would also like to point out the sheer genius of those people who
pioneered this field (See the credits on the SPF site). I think they knew
what they had, but I don't think others see the magnitude of it -- yet.

- --
Jonathan M. Gardner
Mass Mail Systems Developer, Amazon.com
jonagard(_at_)amazon(_dot_)com
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Jonathon,

While I think many on the list appreciate your enthusiasm, your logic
doesn't fit reality. An assertion that a particular mail server is
legitimate for sending mail from a particular domain does not
automatically mean that liability for that person/organization
follows.

Consider the real world today. You find that a bad person has done bad
things using an Amazon mail server against your AUP. There was nothing
that a reasonable person could have done to anticipate the method that
the person used to abuse your mail server. For arguments sake let us
say that 100k of spam was sent from your server before it was shut
down (a matter of 30 minutes or so...again, for arguments sake).

There isn't a court in the world that would hold Amazon liable for damages.

So let's continue down this path. Amazon security investigates and
tracks down the originating host that connected to their mail server.
It turns out that it is a DSL connection and belongs to Grandma Moses.
Think there is a court that is going to hold her liable for her
trojaned machine?

So let's say you actually track down the person that trojaned grandmas
machine. Which jurisdiction is going to (today) do anything meaningful
to that person?

Is your company going to act as a complainant or go after them for
civil damages? I doubt it. The discussion with your legal consul is
going to be along the lines of.... we don't want to be subject to
discovery, depositions, etc. We simply don't want to take the risks of
being in the public eye over something like this.

Your company will apologize to anyone who complains or at least say
you will look into it. You will do damage control.

Bottom line.... taking responsibility and/or doing the right thing
does not automagically translate into liability.

Mike Hammer