Re: [ietf-smtp] G.7.3 --- resolvable FQDNs

Michael Peddemors <> Mon, 10 August 2020 16:43 UTC

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From: Michael Peddemors <>
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Date: Mon, 10 Aug 2020 09:43:51 -0700
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Subject: Re: [ietf-smtp] G.7.3 --- resolvable FQDNs
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On 2020-08-07 7:08 p.m., John Levine wrote:
> In article <22051.1596843872@localhost> you write:
>> The explicit discussion was that in some non-Internet contexts, the domain
>> name is not from the DNS.
> I don't understand what that has to do with writing specs that
> interoperate on the Internet. If a host is sending mail on the
> Internet, it looks names up in the DNS.
> Most mail servers have a hack that lets you put in routes manually to
> locally override the DNS results, but I've never heard anyone say the
> details of that should be standardized. Certainly in the MTAs I've
> used, the way you do so has varied all over the place.
> R's,
> John

Just a thought, is this maybe time to enshrine some of the MAAWG 
recommendations surrounding this?

If your email server egress IP has a PTR of:

There SHOULD be a URL that responds to, where 
information and contact information about the operator can be found..

Also, some operators still find a need for multiple PTR's for an IP, and 
some language around avoiding too many PTR records for the same IP, and 
that EACH PTR should have an associated A record and functioning URL.

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