Matthias Schmidt [c] wrote:
Am/On Mon, 16 Jul 2007 06:11:32 -0700 schrieb/wrote Marc Perkel:
One of the problems with SMTP in my opinion is that it allows end users
to talk on port 25 to servers and therefore can't be distinguished from
server to server traffic.
Imagine a policy where ISPs blocked port 25 for consumers by default and
forced them to talk to mail servers on port 587 to send SMTP. Suppose
that all SMTP servers who took email from consumers had port 587 open as
well as port 25.
If port 25 were blocked from consumers and they were forced to talk to
servers on port 587, even without authentication, then a server could
distinguish consumers from other servers. I think this kind of
configuration could be used to help isolate virus infected computers
>from spamming and spreading.
So if I have an SMTP server that is set up to receive email for a bunch
of domains and had port 587 closed then I could block out all spam from
consumer computers. The idea being that a lot of virus infected spam
bots would be isolated. It would force consumer traffic to talk only to
smtp servers set up to relay consumer email.
Thoughts?
imho this won't work ...
how you want to keep infected computers off from 25?
Many ISPs firewall 25 at the edge of their network. If you try to send
to port 25 on their network or to their SMTP they allow that traffic.
One of the reasons for running the submission port is so that your users
can get out of those ISPs to your outgoing server.
For another way of doing this, see the PBL:
http://www.spamhaus.org/pbl/index.lasso
