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

Ted Lemon <> Wed, 06 January 2021 17:10 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 747763A1016 for <>; Wed, 6 Jan 2021 09:10:31 -0800 (PST)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -1.898
X-Spam-Status: No, score=-1.898 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, HTML_MESSAGE=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=unavailable autolearn_force=no
Authentication-Results: (amavisd-new); dkim=pass (2048-bit key)
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id uqRCv0PT8lrw for <>; Wed, 6 Jan 2021 09:10:30 -0800 (PST)
Received: from ( [IPv6:2607:f8b0:4864:20::f2d]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 098313A1014 for <>; Wed, 6 Jan 2021 09:10:29 -0800 (PST)
Received: by with SMTP id d11so1499953qvo.11 for <>; Wed, 06 Jan 2021 09:10:29 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20150623; h=from:message-id:mime-version:subject:date:in-reply-to:cc:to :references; bh=yt0ZHOktr4ML5Bf/HT33ja6/SmubbXEHNR3xroi0C9I=; b=aHAqRW0AYIzhoCCN7rAUqyOILKC6TvSWWpOdGclj1XR7fInSpCy2YlrLM5e3DimzaK wpkxQXr2mFr8mx/xGqGbRL0flnufZvXfq+9DP4dwOE1PUxJZrv1YSqgbdAmsH7N0Z4gK 7wARfnQhiQmFNMjyR1xD0c3crDzoDg2DL0zYiChwXg7HoaSwLlIpw50RJ0J2GyuIHSjf WJpuT8hxhbRX0cEYphwSy5YGVtagbsJNZ8TrA1OP6giTAtA2oH6BfSNGpmym29/ETRUI EpcZ6BAYro9Wd6dDJJFMDZo25o3NP3tuDqcejg9nTYTZYnEmWA8wjVZmSQqRm13q876Q QvqA==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20161025; h=x-gm-message-state:from:message-id:mime-version:subject:date :in-reply-to:cc:to:references; bh=yt0ZHOktr4ML5Bf/HT33ja6/SmubbXEHNR3xroi0C9I=; b=e48dVtG46/dWk24o6QhfeHioPtkIAQoT8iOupCKN/iUUDxjqkn/q5UPx0GAfztxMhr GxBepSYBitBRPieLZHHa1YG3S7N7vdr+5nTI4SJNoG9b5vlfGIDLkVg+9fccW36nGD3R VBJ2J8rdtLc0ujn2MwXGqBW6qqYe/Ivg4BuESVo9pAUbERRnOZEFSqKsYYcnjx5KdMhQ HjV71SKgo9KJ9BRX0ryonDhCQ4O20AJ6cDYhg4YcyNIGkx3T+cJ8r3Ckgt84UmZUHxJK nsRonPRiI391gNHKhpuPOv7gwaoJsI4wAA+n4xGcZI8/UeYMcoqVzZ/8IfqTEdG1wR8Q UOZg==
X-Gm-Message-State: AOAM530mNYG5QKXud4HIn9G4jmbW+Tx52Zq13o6bx/ievwAL4RT2/6q6 A+9WoLrcm68vPO3oPIsg4Uc/WQ==
X-Google-Smtp-Source: ABdhPJwfBN5Q4ugTr51+dHCH70g66tSA+6GVvO2bXXYDoDhL+XFGOOTMmn3vOBYs9E4NZfRHl0lVfA==
X-Received: by 2002:a05:6214:487:: with SMTP id ay7mr4705144qvb.37.1609953029088; Wed, 06 Jan 2021 09:10:29 -0800 (PST)
Received: from mithrandir.lan ( []) by with ESMTPSA id r22sm1607040qkk.67.2021. (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 06 Jan 2021 09:10:28 -0800 (PST)
From: Ted Lemon <>
Message-Id: <>
Content-Type: multipart/alternative; boundary="Apple-Mail=_709B8E6A-B91B-489C-92F8-A4AD0698AE32"
Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.\))
Date: Wed, 6 Jan 2021 12:10:26 -0500
In-Reply-To: <>
Cc: Gert Doering <>, IPv6 Operations <>, Philip Homburg <>,
To: Fernando Gont <>
References: <> <> <> <> <> <> <20210106162652.GX13005@Space.Net> <>
X-Mailer: Apple Mail (2.3654.
Archived-At: <>
Subject: Re: [v6ops] Scope of Unique Local IPv6 Unicast Addresses (Fwd: New Version Notification for draft-gont-6man-ipv6-ula-scope-00.txt)
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: v6ops discussion list <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Wed, 06 Jan 2021 17:10:31 -0000

On Jan 6, 2021, at 11:46 AM, Fernando Gont <> wrote:
> I have Raspberry Pis that deploy here and there. In order to be able to access them, they use dynamic DNS to post their addresses on their DNS.
> If I don't look at the properties of the addresses, then I end up puting crap on the DNS. One straightforward consequence is that many apps that don't do Happy Eyeballs end up having an insane connection-establishment period, if they happen to try the unusable addresses first.
> So "find all your IPv6 addresses and post them to the DNS" doesn't work.

It is of course not even obvious how to solve this, because sometimes you do want ULA in DNS, and sometimes you don’t. And it depends on what DNS. If you are doing split DNS, then you can scope the DNS that advertises ULAs only to serve those networks where those ULAs are in-scope. The DNS that is advertised globally would of course contain no ULAs. How this is arranged is either a matter of local configuration or an interesting topic of future work, depending on how you look at it.