nanog mailing list archives

Re: ingress SMTP


From: "Jay R. Ashworth" <jra () baylink com>
Date: Wed, 3 Sep 2008 12:49:41 -0400

On Wed, Sep 03, 2008 at 09:40:20AM -0700, Michael Thomas wrote:
"Allowing unfiltered public access to port 25 is one of the things that
increases everyone's spam load, and your ISP is trying to be a Good
Neighbor in blocking access to anyone's servers but their own; many ISPs
are moving towards this safer configuration. We're a good neighbor, as
well, and support Mail Submission Protocol on port 587, and here's how
you set it up -- and it will work from pretty much anywhere forever."

I think this all vastly underrates the agility of the bad guys. So lots of
ISP's have blocked port 25. Has it made any appreciable difference?
Not that I can tell. If you block port 25, they'll just use another port and
a relay if necessary.

You're forgetting that 587 *is authenticated, always*.

The issue here, though, was that of an Enhanced Mail Provider's clients
being unable to get through blocks *set by their client's ISPs*.

The EMP has no control over that except to switch said clients to MSP
(which they really should have done to begin with, as someone else
notes).

Cheers,
-- jra
-- 
Jay R. Ashworth                   Baylink                      jra () baylink com
Designer                     The Things I Think                       RFC 2100
Ashworth & Associates     http://baylink.pitas.com                     '87 e24
St Petersburg FL USA      http://photo.imageinc.us             +1 727 647 1274

             Those who cast the vote decide nothing.
             Those who count the vote decide everything.
               -- (Josef Stalin)


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