nanog mailing list archives

Re: ingress SMTP


From: "Jay R. Ashworth" <jra () baylink com>
Date: Wed, 3 Sep 2008 12:14:00 -0400

On Wed, Sep 03, 2008 at 11:56:51AM -0400, Justin Scott wrote:
As a small player who operates a mail server used by many local 
businesses, this becomes a support issue for admins in our position.  We 
operate an SMTP server of our own that the employees of these various 
companies use from work and at home.  Everything works great until an 
ISP decides to block 25 outbound.  Now our customer cannot reach our 
server, so they call us to complain that they can receive but not send 
e-mail.  We, being somewhat intelligent, have a support process in place 
to walk the customer through the SMTP port change from 25 to one of our 
two alternate ports.

The problem, however, is that the customer simply cannot understand why 
their e-mail worked one day and doesn't the next.  In their eyes the 
system used to work, and now it doesn't, so that must mean that we broke 
it and that we don't know what we're doing.

I feel your pain, local compadre, but I'm on their side.

Here's your script:

"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."

Which is a safe thing to tell people because it is decidedly *not* best
practice to block 587.

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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