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

Keith Moore <> Sun, 04 October 2020 21:57 UTC

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To: John Levine <>,
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From: Keith Moore <>
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Date: Sun, 4 Oct 2020 17:57:14 -0400
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Subject: Re: [ietf-smtp] EHLO domain validation requirement in RFC 5321
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On 10/4/20 5:46 PM, John Levine wrote:

> *  Do not host your email system ‘in the cloud’
>> I'm not sure what this actually means or why it's still a bad idea.
>> Cloud hosting makes a lot of sense for various reasons.
> It's a bad neighborhood, since you can expect your neighbors to be
> poorly managed botted spam-spewing web servers. It varies by cloud
> provider but the median is pretty bad.

Is it really fair to assess senders based on their "neighborhoods"?    
At what point does this depart from common sense and into the realm of 
pure prejudice?  ("That IP address is from across the tracks, which is a 
bad part of the net.")

And again, what does "in the cloud" actually mean?   Is renting a server 
in a rack at some hosting provider really better than renting a VM, or 
is it necessary to originate mail from your own address block that's 
routed to your enterprise network?

In most respects outsourcing of server provisioning, maintenance, and 
connectivity has become normal, widely accepted, often recommended 
practice.   Why should email be different?

It's hard to escape the impression that a lot of spam filters are based 
on imposing completely arbitrary restrictions on senders, on the belief 
that "good senders" will know which hoops they have to jump through (and 
have sufficient funding to do so) while "bad senders" won't.

>> Is there a more recent standard for doing so than postmaster@?
> Um, RFC 2142 published 23 years ago.

ok fine.   I was wondering if some sort of other channel for this had 
been established in the last couple of decades, that I hadn't heard of.