"Alan DeKok" <aland(_at_)ox(_dot_)org> wrote:
"Dag Kihlman" <dag(_dot_)kihlman(_at_)htu(_dot_)se> wrote:
The failing of SMTP is that it allows the sender to cheat or lie. Any
authentication in SMTP is just authentication in an academic sense. In
reality spammers will hack even more than today and send using fully
authenticated mail servers.
Pull systems do not change this behaviour. See recent spammer
behaviour of hosting web sites on trojaned machines. They could just
as easily host mail for a "pull" system on the trojaned machine.
The benefits of a pull system are different. It allows recipients
to do things like wait 12 hours to pick up mail from unknown senders,
at which point the trojaned machine probably has a different IP, and
thus can't send the spam.
Why on earth should computers with dynamic IP addresses be allowed to host
mail in a pull system??? My suggestion was that all traffic to the pull
server ports are forbidden to dynamic IP addresses. The ISP:s must enforce
this rule or they will be cut off too.
at which point the trojaned machine probably has a different IP
No, no, no!!! Do not trust on that! In theory I have a dynamic IP-address.
In reality it has not changed for three months. Several of my friends
experience the same thing. Your suggestion makes mine and tens of thousands
similar cable modem machines honey pots for spammers. With my suggestion
they are uninteresting. The fewer the honey pots are the more costly it will
be to find them and the fewer the spammers will be.
If I want to install a pull server I ought to subscribe to a static IP
address and pay some fee for having the ports opened. (The market will make
this fee reasonable)
When I say spammers can not lie in a pull system I mean they must be honest
about their IP-address. Any other honesty is unfortunately not possible on
the Internet.
/DK
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