Re: [ietf-smtp] EHLO domain validation requirement in RFC 5321

John R Levine <johnl@taugh.com> Sun, 27 September 2020 16:53 UTC

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Date: 27 Sep 2020 12:53:36 -0400
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From: "John R Levine" <johnl@taugh.com>
To: "John C Klensin" <john@jck.com>, ietf-smtp@ietf.org
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Subject: Re: [ietf-smtp] EHLO domain validation requirement in RFC 5321
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> This is a self-fulfilling prophecy which gets back to Keith's
> comment about resources.  In order to run an SMTP client or
> server with any of the three ISPs I've dealt with recently, and
> do so without violating the contracts they impose, I first have
> to obtain a business account which is not much different from a
> residential account other than costing three or four times as
> much. ...

For reasons many but not all of which are related to Redmond WA, 
residential networks are so thoroughly infected with botnets that ISPs 
block outbound port 25 connections out of self defense.  They can't afford 
to deal with the complaints otherwise.

On the other hand, if you want to run your own mail server, setting up a 
BSD or Linux VPS with matching f/rDNS is not hard and not expensive.  I 
have a tiny one (20GB disk, 512MB RAM, 1TB/mo) for $27/yr and a reasonably 
cqpable one (30GB/1GB/2TB) for $43.20/yr.  To set the rDNS I just put in a 
ticket which they typically handle within a few hours, no extra charge. I 
presume they check that there's forward DNS to match.

R's,
John