Re: [v6ops] [EXTERNAL] Re: Scope of Unique Local IPv6 Unicast Addresses (Fwd: New Version Notification for draft-gont-6man-ipv6-ula-scope-00.txt)

Gert Doering <> Tue, 16 February 2021 15:27 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id F14CF3A0F0C for <>; Tue, 16 Feb 2021 07:27:34 -0800 (PST)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -2.099
X-Spam-Status: No, score=-2.099 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: (amavisd-new); dkim=pass (2048-bit key)
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id 6K2ZvwAIavBG for <>; Tue, 16 Feb 2021 07:27:33 -0800 (PST)
Received: from ( [IPv6:2001:608:3:85::38]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 8AACD3A0F02 for <>; Tue, 16 Feb 2021 07:27:31 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple;;; q=dns/txt; s=esa; t=1613489252; x=1645025252; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=LN/wgvQNwPYhYnqlZ3suYJVWTOvuEbi7pH46CYq4QUI=; b=awhPRKBtQzEDF6gjEeG5G2zF78p2cMcr8kqKcfbt9zmehRBBJSpclje/ TG10urkkWIP36SY/QARMoKU8M3KaF+/6tzsjnAkjm5AScRGe0EMOXpp8v nbX9O/U10Ti8G/rQDD8X02v6jDJ5LIVEujdRjYu/QtIOignK6+yDCKUvk x9e59K+2/+Zb0Gw7cFuGrtFD3RKzHtJVS9gYz9SV7RqmCsB0H2gb8gK1q aURvO6Xjx6YizlRCCaBe4Z9Ipsg1FlTaPtYbQ20Cn0CVF56wafYA9dDUQ UHNaUKr/7d0QaViHbEH/y48vDtrqeUbAgFgvSdX3j0DVFC2aUe3zjFikf w==;
IronPort-SDR: uNdXMEdHd75XHykpjrKRsB0zp91Ot58n3Peg00jTP81qfWqrNqvCdRULCXzQwr6BAeZFUg4MGA fiRHh1WEI3rCeiA5iE76mAFhibPPa1x9lYQG/jlAzTEs/FVEVb+W+ycQWKQ7qkJhqjk0lsT+Mt t17+/77uB5o1lcBW9K4T/VjuZnrJsMlVdkGj9jZ+ijLYAokCFQAt6KBaCyn/SlVa09fdg7upOH 9Weev560jTg6/2HIv9d1MnNKqdSxnLqY/GME1sZVbgA/YvhxXfpSCaTIBt4bH/16an93OD/fSQ n4g=
X-SpaceNet-SBRS: None
Received: from ([]) by with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Feb 2021 16:27:30 +0100
Received: from (localhost [IPv6:::1]) by (Postfix) with ESMTP id 2C65243B82 for <>; Tue, 16 Feb 2021 16:27:30 +0100 (CET)
X-SpaceNet-Relay: true
X-SpaceNet-Relay: true
X-SpaceNet-Relay: true
X-SpaceNet-Relay: true
Received: from ( [IPv6:2001:608:2:2::251]) by (Postfix) with ESMTP id CCD4143AEC; Tue, 16 Feb 2021 16:27:29 +0100 (CET)
Received: by (Postfix, from userid 1007) id C6668F77A3; Tue, 16 Feb 2021 16:27:29 +0100 (CET)
Date: Tue, 16 Feb 2021 16:27:29 +0100
From: Gert Doering <>
To: Philip Homburg <>
Cc:, Fernando Gont <>, "" <>
Subject: Re: [v6ops] [EXTERNAL] Re: Scope of Unique Local IPv6 Unicast Addresses (Fwd: New Version Notification for draft-gont-6man-ipv6-ula-scope-00.txt)
Message-ID: <YCvkYXwTrSdQoe8Q@Space.Net>
References: <> <> <> <> <> <> <> <> <> <>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <>
Archived-At: <>
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "IPv6 Maintenance Working Group \(6man\)" <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Tue, 16 Feb 2021 15:27:35 -0000


On Tue, Feb 16, 2021 at 04:20:14PM +0100, Philip Homburg wrote:
> With ULA, using the ULA as source address is not going to connect you the
> wider IPv6 internet. NAT is unlikely. But there is a good chance that there
> is another IPv6 address that can reach the rest of the internet.

I would not codify this.

Given the failure of dual-GUA multihoming, I expect to see quite a bit
of ULA + double-NPT6 multihoming in the not-so-far-future.

(And yes, it pains me, and I'm happy to be proven wrong.  But my gut
has lots of experience now with "will people use this perfect solution
which is only 80% implemented yet" vs "will they do something that smells
bad, but works right away"...)

Gert Doering
        -- NetMaster
have you enabled IPv6 on something today...?

SpaceNet AG                      Vorstand: Sebastian v. Bomhard, Michael Emmer
Joseph-Dollinger-Bogen 14        Aufsichtsratsvors.: A. Grundner-Culemann
D-80807 Muenchen                 HRB: 136055 (AG Muenchen)
Tel: +49 (0)89/32356-444         USt-IdNr.: DE813185279