Re: [DNSOP] Terminology question: split DNS

Paul Vixie <> Mon, 19 March 2018 17:54 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 37CDF127333 for <>; Mon, 19 Mar 2018 10:54:52 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -1.911
X-Spam-Status: No, score=-1.911 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, SPF_PASS=-0.001, T_RP_MATCHES_RCVD=-0.01] autolearn=ham autolearn_force=no
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id nFwLDba1GruN for <>; Mon, 19 Mar 2018 10:54:50 -0700 (PDT)
Received: from ( []) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 77478126C25 for <>; Mon, 19 Mar 2018 10:54:50 -0700 (PDT)
Received: from [] ( []) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) by (Postfix) with ESMTPSA id C1C2F7594C; Mon, 19 Mar 2018 17:54:49 +0000 (UTC)
Message-ID: <>
Date: Mon, 19 Mar 2018 10:54:48 -0700
From: Paul Vixie <>
User-Agent: Postbox 5.0.24 (Windows/20180302)
MIME-Version: 1.0
To: Paul Hoffman <>
CC: dnsop <>
References: <>
In-Reply-To: <>
Content-Type: text/plain; charset="ISO-8859-1"; format="flowed"
Content-Transfer-Encoding: 7bit
Archived-At: <>
Subject: Re: [DNSOP] Terminology question: split DNS
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: IETF DNSOP WG mailing list <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Mon, 19 Mar 2018 17:54:52 -0000

Paul Hoffman wrote:
> Some folks had reservations about the current definition of "split
> DNS": "Where a corporate network serves up partly or completely
> different DNS inside and outside its firewall. There are many
> possible variants on this; the basic point is that the correspondence
> between a given FQDN (fully qualified domain name) and a given IPv4
> address is no longer universal and stable over long periods." (Quoted
> from <xref target="RFC2775"/>, Section 3.8)
> What would the WG like for this definition?

my only qualm is that A and AAAA RR's are not the only things that are 
usually not the same when DNS is split in this way. MX, NS, SRV, and 
likely a dozen others, and DNSSEC signatures and keys, can also differ.

it should be called split-horizon DNS not split-DNS, to highlight the 
fact that it's the same zone name in an entirely separate DNS namespace.

P Vixie