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

John Levine <johnl@taugh.com> Tue, 11 August 2020 02:49 UTC

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Date: 10 Aug 2020 22:49:15 -0400
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From: "John Levine" <johnl@taugh.com>
To: ietf-smtp@ietf.org
Cc: michael@linuxmagic.com
In-Reply-To: <58713b65-01a4-f07f-5fe4-6876001c20d1@linuxmagic.com>
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Subject: Re: [ietf-smtp] G.7.3 --- resolvable FQDNs
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In article <58713b65-01a4-f07f-5fe4-6876001c20d1@linuxmagic.com> you write:
>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:
>
>mail.example.com
>
>There SHOULD be a URL that responds to http://example.com, where 
>information and contact information about the operator can be found..

Can you give us a pointer to the document that says that?  I've read a
lot of M3 documents and don't recall seeing it.

>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.

I don't see the point here. Unless you're doing MTA-STS, which is a
separate spec, an MTA doesn't know what name a client thinks it has.

R's,
John
-- 
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John Levine, johnl@taugh.com, Primary Perpetrator of "The Internet for Dummies",
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